Why do these earthworms stay between the road lines?

Why do these earthworms stay between the road lines?

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This article shows pictures of earthworms during floods in Texas. The worms ball up, supposedly in order to survive the floods.

Photo Credit: Texas Parks And Wildlife Department

Can anyone explain the phenomenon a little? I can't seem to find anything about this online. I know that earthworms surface when it rains for oxygen, but it seems weird that they meet in the middle of the street.

The first question: what the worms do on the ground during the flood? One of the answers to this question is -

"It gives them an opportunity to move greater distances across the soil surface than they could do through soil," said Dr. Lowe. "They cannot do this when it is dry because of their moisture requirements."

The second question: why they form ball after moving to the ground. There are two answers to this question:

First, as a part of surviving mechanism to prevent drying. As you can see, they cannot come back to the soil across the asphalt, thus they form balls and wait the weather to improve.

Second reason to form the balls - communication:

"The earthworms use touch to communicate and influence each other's behaviour, according to research published in the journal Ethology. By doing so the worms collectively decide to travel in the same direction as part of a single herd."

I think another aspect to this has actually nothing to do with worm biology and instead relates to the roads and cars:

  1. Roads are typically graded so that water runoff moves off the roads -- this usually means that the center line(s) are a high point in the road.

    • See here for example

    • As a result, the worms would experience the least amount of water and runoff force if they congregated in the middle.

  2. Two "forces" could prevent formation of balls in the middle of either lane.

    • Water runoff might be stronger there preventing a stable "footing" for the worms to remain.

    • Even if balls formed in the lanes, car traffic would almost certainly destroy them leaving little evidence of them behind (especially if rain was washing them away).

I'm sure the other answers play a part in this phenomenon aswell, but I was taught that worms do this because the worms dont have eyes, yet they still can sense light from dark, because staying out in the sun too long would dry them out, So they are between 2 yellow lines (to them they think that must be light) and the middle line is dark (the asphalt itself) so ultimately the worms are very confused and think they are somewhere safe and dark (like underground) They pass the first line trying to get through the light in search of darkness, and get stuck in the middle because they think the next line is more light. They sadly believe they have found a safe haven.

Heartworm Basics

Heartworm disease is a serious and potentially fatal disease in pets in the United States and many other parts of the world. It is caused by foot-long worms (heartworms) that live in the heart, lungs and associated blood vessels of affected pets, causing severe lung disease, heart failure and damage to other organs in the body. Heartworm disease affects dogs, cats and ferrets, but heartworms also live in other mammal species, including wolves, coyotes, foxes, sea lions and—in rare instances—humans. Because wild species such as foxes and coyotes live in proximity to many urban areas, they are considered important carriers of the disease.

Dogs. The dog is a natural host for heartworms, which means that heartworms that live inside the dog mature into adults, mate and produce offspring. If untreated, their numbers can increase, and dogs have been known to harbor several hundred worms in their bodies. Heartworm disease causes lasting damage to the heart, lungs and arteries, and can affect the dog’s health and quality of life long after the parasites are gone. For this reason, heartworm prevention for dogs is by far the best option, and treatment—when needed—should be administered as early in the course of the disease as possible. Learn more about heartworm medicine for dogs.

Cats. Heartworm disease in cats is very different from heartworm disease in dogs. The cat is an atypical host for heartworms, and most worms in cats do not survive to the adult stage. Cats with adult heartworms typically have just one to three worms, and many cats affected by heartworms have no adult worms. While this means heartworm disease often goes undiagnosed in cats, it’s important to understand that even immature worms cause real damage in the form of a condition known as heartworm associated respiratory disease (HARD). Moreover, the medication used to treat heartworm infections in dogs cannot be used in cats, so prevention is the only means of protecting cats from the effects of heartworm disease.

Ferrets. Heartworm disease in ferrets is caused by the same parasite that causes heartworm infection in dogs and cats. The disease in ferrets is an odd mix of the disease that we see in dogs and cats. Like dogs, ferrets are extremely susceptible to infection and can have larger numbers of worms than cats, but like cats, a low number of worms, perhaps just one, can cause devastating disease due to the small size of the heart. Heartworm disease is often more difficult to diagnose in ferrets and there is no approved treatment. Prevention is imperative for both indoor and outdoor ferrets.

How is heartworm disease transmitted from one pet to another?

The mosquito plays an essential role in the heartworm life cycle. Adult female heartworms living in an infected dog, fox, coyote, or wolf produce microscopic baby worms called microfilaria that circulate in the bloodstream. When a mosquito bites and takes a blood meal from an infected animal, it picks up these baby worms, which develop and mature into “infective stage” larvae over a period of 10 to 14 days. Then, when the infected mosquito bites another dog, cat, or susceptible wild animal, the infective larvae are deposited onto the surface of the animal's skin and enter the new host through the mosquito’s bite wound. Once inside a new host, it takes approximately 6 months for the larvae to develop into sexually mature adult heartworms. Once mature, heartworms can live for 5 to 7 years in dogs and up to 2 or 3 years in cats. Because of the longevity of these worms, each mosquito season can lead to an increasing number of worms in an infected pet.

What are the signs of heartworm disease in dogs?

In the early stages of the disease, many dogs show few symptoms or no symptoms at all. The longer the infection persists, the more likely symptoms will develop. Active dogs, dogs heavily infected with heartworms, or those with other health problems often show pronounced clinical signs.

Signs of heartworm disease may include a mild persistent cough, reluctance to exercise, fatigue after moderate activity, decreased appetite, and weight loss. As heartworm disease progresses, pets may develop heart failure and the appearance of a swollen belly due to excess fluid in the abdomen. Dogs with large numbers of heartworms can develop a sudden blockages of blood flow within the heart leading to a life-threatening form of cardiovascular collapse. This is called caval syndrome, and is marked by a sudden onset of labored breathing, pale gums, and dark bloody or coffee-colored urine. Without prompt surgical removal of the heartworm blockage, few dogs survive.

What are the signs of heartworm disease in cats?

Signs of heartworm disease in cats can be very subtle or very dramatic. Symptoms may include coughing, asthma-like attacks, periodic vomiting, lack of appetite, or weight loss. Occasionally an affected cat may have difficulty walking, experience fainting or seizures, or suffer from fluid accumulation in the abdomen. Unfortunately, the first sign in some cases is sudden collapse of the cat, or sudden death.

What are the signs of heartworm disease in ferrets?

The signs of heartworm disease in ferrets are similar to those in dogs, but they develop more rapidly because the ferret’s heart is quite small. While dogs may not show symptoms until they have many worms infecting their hearts, lungs and blood vessels, just one worm can cause serious respiratory distress in a ferret. Symptoms of this distress include • Lethargy (i.e., fatigue, tiredness) • Open-mouth and/or rapid breathing • Pale blue or muddy gum color • Coughing

How significant is my pet's risk for heartworm infection?

Many factors must be considered, even if heartworms do not seem to be a problem in your local area. Your community may have a greater incidence of heartworm disease than you realize—or you may unknowingly travel with your pet to an area where heartworms are more common. Heartworm disease is also spreading to new regions of the country each year. Stray and neglected dogs and certain wildlife such as coyotes, wolves, and foxes can be carriers of heartworms. Mosquitoes blown great distances by the wind and the relocation of infected pets to previously uninfected areas also contribute to the spread of heartworm disease (this happened following Hurricane Katrina when 250,000 pets, many of them infected with heartworms, were “adopted” and shipped throughout the country).

The fact is that heartworm disease has been diagnosed in all 50 states, and risk factors are impossible to predict. Multiple variables, from climate variations to the presence of wildlife carriers, cause rates of infections to vary dramatically from year to year—even within communities. And because infected mosquitoes can come inside, both outdoor and indoor pets are at risk.

For that reason, the American Heartworm Society recommends that you “think 12:” (1) get your pet tested every 12 months for heartworm and (2) give your pet heartworm preventive 12 months a year.

What do I need to know about heartworm testing?

Heartworm disease is a serious, progressive disease. The earlier it is detected, the better the chances the pet will recover. There are few, if any, early signs of disease when a dog, cat or ferret is infected with heartworms, so detecting their presence with a heartworm test administered by a veterinarian is important. The test requires just a small blood sample from your pet, and it works by detecting the presence of heartworm proteins. Some veterinarians process heartworm tests right in their hospitals while others send the samples to a diagnostic laboratory. In either case, results are obtained quickly. If your pet tests positive, further tests may be ordered.

When should my pet be tested?

Testing procedures and timing differ somewhat between dogs, cats and ferrets.

Dogs. All dogs should be tested annually for heartworm infection, and this can usually be done during a routine visit for preventive care. Following are guidelines on testing and timing:

  • Puppies under 7 months of age can be started on heartworm prevention without a heartworm test (it takes at least 6 months for a dog to test positive after it has been infected), but should be tested 6 months after your initial visit, tested again 6 months later and yearly after that to ensure they are heartworm-free.
  • Adult dogs over 7 months of age and previously not on a preventive need to be tested prior to starting heartworm prevention. They, too, need to be tested 6 months and 12 months later and annually after that.
  • You need to consult your veterinarian, and immediately re-start your dog on monthly preventive—then retest your dog 6 months later. The reason for re-testing is that heartworms must be approximately 7 months old before the infection can be diagnosed.

Annual testing is necessary, even when dogs are on heartworm prevention year-round, to ensure that the prevention program is working. Heartworm medications are highly effective, but dogs can still become infected. If you miss just one dose of a monthly medication—or give it late—it can leave your dog unprotected. Even if you give the medication as recommended, your dog may spit out or vomit a heartworm pill—or rub off a topical medication. Heartworm preventives are highly effective, but not 100 percent effective. If you don’t get your dog test, you won’t know your dog needs treatment.

Cats. Heartworm infection in cats is harder to detect than in dogs, because cats are much less likely than dogs to have adult heartworms. The preferred method for screening cats includes the use of both an antigen and an antibody test (the “antibody” test detects exposure to heartworm larvae). Your veterinarian may also use x-rays or ultrasound to look for heartworm infection. Cats should be tested before being put on prevention and re-tested as the veterinarian deems appropriate to document continued exposure and risk. Because there is no approved treatment for heartworm infection in cats, prevention is critical.

Ferrets. Diagnosis of heartworm disease in ferrets can be more problematic. Your veterinarian may recommend both antigen testing and diagnostic imaging such as echocardiography to demonstrate the presence of worm in the heart.

What happens if my dog tests positive for heartworms?

No one wants to hear that their dog has heartworm, but the good news is that most infected dogs can be successfully treated. The goal is to first stabilize your dog if he is showing signs of disease, then kill all adult and immature worms while keeping the side effects of treatment to a minimum.

Here's what you should expect if your dog tests positive:

  • Confirm the diagnosis. Once a dog tests positive on an antigen test, the diagnosis should be confirmed with an additional—and different—test. Because the treatment regimen for heartworm is both expensive and complex, your veterinarian will want to be absolutely sure that treatment is necessary.
  • Restrict exercise. This requirement might be difficult to adhere to, especially if your dog is accustomed to being active. But your dog’s normal physical activities must be restricted as soon as the diagnosis is confirmed, because physical exertion increases the rate at which the heartworms cause damage in the heart and lungs. The more severe the symptoms, the less activity your dog should have.
  • Stabilize your dog's disease. Before actual heartworm treatment can begin, your dog’s condition may need to be stabilized with appropriate therapy. In severe cases of heartworm disease, or when a dog has another serious condition, the process can take several months.
  • Administer treatment. Once your veterinarian has determined your dog is stable and ready for heartworm treatment, he or she will recommend a treatment protocol involving several steps. The American Heartworm Society has guidelines for developing this plan of attack. Dogs with no signs or mild signs of heartworm disease, such as cough or exercise intolerance, have a high success rate with treatment. More severe disease can also be successfully treated, but the possibility of complications is greater. The severity of heartworm disease does not always correlate with the severity of symptoms, and dogs with many worms may have few or no symptoms early in the course of the disease.
  • Test (and prevent) for success. Approximately 9 months after treatment is completed, your veterinarian will perform a heartworm test to confirm that all heartworms have been eliminated. To avoid the possibility of your dog contracting heartworm disease again, you will want to administer heartworm prevention year-round for the rest of his life.

What if my cat tests positive for heartworms?

Like dogs, cats can be infected with heartworms. There are differences, however, in the nature of the disease and how it is diagnosed and managed. Because a cat is not an ideal host for heartworms, some infections resolve on their own, although these infections can leave cats with respiratory system damage. Heartworms in the circulatory system also affect the cat’s immune system and cause symptoms such as coughing, wheezing and difficulty breathing. Heartworms in cats may even migrate to other parts of the body, such as the brain, eye and spinal cord. Severe complications such as blood clots in the lungs and lung inflammation can result when the adult worms die in the cat’s body.

Here’s what to expect if your cat tests positive for heartworm:

  • Diagnosis. While infected dogs may have 30 or more worms in their heart and lungs, cats usually have 6 or fewer—and may have just one or two. But while the severity of heartworm disease in dogs is related to the number of worm, in cats, just one or two worms can make a cat very ill. Diagnosis can be complicated, requiring a physical exam, an X-ray, a complete blood count and several kinds of blood test. An ultrasound may also be performed.
  • Treatment. Unfortunately, there is no approved drug therapy for heartworm infection in cats, and the drug used to treat infections in dogs is not safe for cats. Nevertheless, cats with heartworm disease can often be helped with good veterinary care. The goal is to stabilize your cat and determine a long-term management plan.
  • Monitor your cat. Heartworm-positive cats may experience spontaneous clearing of heartworms, but the damage they cause may be permanent. If your cat is not showing signs of respiratory distress, but worms have been detected in the lungs, chest X-rays every 6 to 12 months may be recommended. If mild symptoms are noted, small doses of prednisolone may be administered to help reduce inflammation.
  • Provide veterinary care. If the disease is severe, additional support may be necessary. Your veterinarian my recommend hospitalization in order to provide therapy, such as intravenous fluids, drugs to treat lung and heart symptoms, antibiotics, and general nursing care. In some cases, surgical removal of heartworms may be possible.
  • Maintain prevention. A cat that has developed heartworm disease has demonstrated that it is susceptible to heartworm infection, and both outdoor and indoor cats are at risk. It’s important to give your cat monthly heartworm preventives, which are available in both spot-on and pill form. Preventives keep new infections from developing if an infected mosquito bites your cat again.

What if my ferret tests positive for heartworms?

Ferrets are extremely susceptible to heartworms.There are differences, however, in the nature of the disease and how it is diagnosed and managed. Ferrets are extremely susceptible to heartworms. Heartworms in the circulatory system also affect the ferret’s immune system and cause symptoms such as coughing, wheezing and difficulty breathing, even sudden death. Ferrets may also demonstrate fluid in the lungs, decreased appetite and weight loss, paralysis of the hind legs, or enlarged abdomen. Bilirubinuria (dark colored urine) is common in ferrets with heartworm disease.

Here’s what to expect if your ferret tests positive for heartworm:

  • Diagnosis. As many as 14 heartworms have been found in a single ferret, but ferrets c an be seriously affected by the presence of only one worm. Diagnosis can be complicated, requiring a physical exam, an X-ray or ultrasound exam, a complete blood count and several kinds of blood test.
  • Treatment. Unfortunately, there is no approved drug therapy for heartworm infection in ferrets, and the drug used to treat infections in dogs is not safe for ferrets. Nevertheless, ferrets with heartworm disease can often be helped with good veterinary care. The goal is to stabilize your pet and determine a long-term management plan.
  • Monitor your ferret. Most ferrets infected with heartworms will be showing clinical signs. If worms have been detected in the lungs, chest X-rays every 6 to 12 months may be recommended. If mild symptoms are noted, small doses of prednisolone may be administered to help reduce inflammation.
  • Provide veterinary care. If the disease is severe, additional support may be necessary. Your veterinarian may recommend hospitalization in order to provide therapy, such as intravenous
    fluids, drugs to treat lung and heart symptoms, antibiotics, and general nursing care. In rare cases, surgical removal of heartworms may be possible.
  • Maintain prevention. Ferrets are very susceptible to heartworm disease and the results of infection may be devastating. Both outdoor and indoor ferrets are at risk and your ferret should be on monthly preventive for life. Preventives keep new infections from developing if an infected mosquito bites your ferrets again.

More questions about heartworm disease

Typically only a few inches in length, some members of this species have been known to grow to a serpentine 14 inches. Earthworms’ bodies are made up of ring-like segments called annuli. These segments are covered in setae, or small bristles, which the worm uses to move and burrow.

Night crawlers are so named because they are usually seen feeding above ground at night. They burrow during the day—typically keeping close to the surface—capable of digging down as deep as 6.5 feet.

The worm’s first segment contains its mouth. As they burrow, they consume soil, extracting nutrients from decomposing organic matter like leaves and roots. Earthworms are vital to soil health because they transport nutrients and minerals from below to the surface via their waste, and their tunnels aerate the ground. An earthworm can eat up to one third its body weight in a day.

Earthworms and Plant Growth - Are They Related?

Earthworms live pretty secret lives underground. Have you ever seen earthworms on the grass or sidewalk after a rain, wriggling back into the soil?

Every animal has a job in the place they live all organisms depend on each other in some way. Since these wiggly bugs share their home with greenery, flowers and shrubs, it's natural to assume that earthworms and plant growth are somehow related.

What do you suppose earthworms do down in the dark, wet soil? Do you think earthworms effect plants in a helpful, harmful or neutral way?


Will a plant with earthworms in its soil grow better, worse or the same as a plant without earthworms in its soil?


  • 2 plastic 2-Liter bottles (or similar plastic containers)
  • Scissors
  • 6 - 12 earthworms
  • Leaves or other dead plant material, such as grass clippings
  • Soil
  • 2 tomato plants
  • Water
  • Access to full sunlight or grow lamps
  • Notebook
  • Pencil
  • Permanent marker


  1. Before you start, consider these questions: What do plants need to grow? How do earthworms behave in their habitat? Earthworms require lots of moisture in their environment to keep them from "drying" out: Where do they spend their time? What would happen if there weren't earthworms in the soil? Write down any notes in your notebook.
  2. Using your notes, make a guess about what will happen to the plant with earthworms, and what will happen to the plant without earthworms. Write down this guess&mdashcalled a hypothesis&mdashin your notebook.
  3. With the help of an adult, cut the top half of each 2-liter bottle off. Discard the tops, or save them for another project down the road.
  4. Using the permanent marker, carefully write "Worms" on one bottle, and "No Worms" on the other.
  5. Pour some of the soil on the bottom of your containers.
  6. Pile the leaves, grass clippings or other dead plant material on top of the soil.
  7. Add another layer of soil.
  8. Plant one tomato plant into the "Worms" bottle, and put the earthworms into the bottle with the plant.
  9. Place the other tomato plant into the "No Worms" bottle, being sure to bury its roots.
  10. Water your tomato plants, and put them side-by-side in a sunny area. Each plant needs at least 6 hours of full sunlight a day.
  11. Using a ruler, measure how tall each plant is. Write down the plant heights in your notebook.
  12. Draw a picture of each plant. Label your drawings "Worms" and "No Worms," and be sure to color or note the color of the leaves and how the soil looks. Are the leaves dark green or light green? Can you clearly see the layers of soil and plant matter? How dark is the soil?
  13. The next day, give each plant a little bit of water (so the soil is damp), examine each plant and record any changes that you see. Repeat this process for 8 days.


After 8 days have passed, look over your daily notes. Draw or write how the soil has changed. Did the color change? Did the texture change? Can you still see the layers of soil and plant matter?

Check the plant growth. Draw or write out what you see. Which plant is greener in color&mdashthe one with the earthworms or the one without? Which plant is bigger? Was your hypothesis right?

Earthworms and plant growth have a special relationship those wiggly worms make a big difference in how a tree blossoms or a flower blooms. The little bugs help the soil become more nutrient-rich by breaking down dead plant materials. This process creates humus, a natural fertilizer that plants use to grow taller and healthier. Earthworms also help plants by making tunnels and holes so the soil gets more air and water to the roots.

Digging Deeper

With science, the learning never stops you can always change an experiment a little bit and get a completely different result! What would happen if you put the plants in the dark? Would the earthworms still be very helpful to plant growth? How about if you skipped adding dead plant material to the soil? Would the earthworms still have an effect on plant growth? Using what you learned in this project, guess what you think will happen&mdashand test to see if you're right.

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Living Science 2019 2020 for Class 7 Science Chapter 20 - Wastewater Management

Living Science 2019 2020 Solutions for Class 7 Science Chapter 20 Wastewater Management are provided here with simple step-by-step explanations. These solutions for Wastewater Management are extremely popular among Class 7 students for Science Wastewater Management Solutions come handy for quickly completing your homework and preparing for exams. All questions and answers from the Living Science 2019 2020 Book of Class 7 Science Chapter 20 are provided here for you for free. You will also love the ad-free experience on Meritnation’s Living Science 2019 2020 Solutions. All Living Science 2019 2020 Solutions for class Class 7 Science are prepared by experts and are 100% accurate.

Page No 238:

Question 1:

Sewage largely consists of wastewater. Where is this wastewater generated?


Wastewater can be generated in houses during bathing, washing clothes and flushing toilets. Moreover, wastewater is also produced by hospitals, industries, offices and hotels.

Page No 238:

Question 2:

Why are open drains considered to be unhygienic?


Open drains are frequently blocked due to plastic bags and sewage. This results in the overflow, which produces foul smell and also provides a breeding ground for germs and mosquitoes. These organisms cause wide range of diseases. This is the reason for open drains to be considered unhygienic.

Page No 238:

Question 3:

No contamination of drinking water can occur if closed pipes are used for drainage of sewage. Is this always true? Explain.


The contamination of drinking water can occur even if closed pipes are used for the drainage of sewage. This is because in many cases, the joints between the sewage lines may be leaky and this can lead to the leakage of sewage. This sewage can mix with the drinking water if the sewage line and water pipeline are proximate to each other.

Page No 240:

Question 1:

What is the aim of sewage treatment?


The basic aim of sewage is to remove solid impurities from the sewage and to make the liquid component of the sewage safer for fish and humans when this sewage is discharged into water bodies.

Page No 240:

Question 2:

Why should you not throw the following into the kitchen sink or flush them down the toilet?
a. cooking oil
b. sanitary napkins
c. paints


a. Cooking oil have the ability to block pipes due to their tendency to harden.

b. Sanitary napkins clog the drains and obstruct with the free flow of oxygen, which is required for the proper decomposition of waste.

c. Paints are toxic to microorganism and kill microbes that are essential for cleaning the water.

Page No 240:

Question 3:

In the aeration tank of a wastewater treatment plant, aerobic bacteria help in getting rid of some contaminants. Name some of these contaminants. How do the bacteria help to remove these contaminants?


The contaminants that can be neutralised by aerobic bacteria are soap, food and faeces. These aerobic bacteria digest these organic contaminants and use them as nutrients.

Page No 241:

Question 1:

Which of these diseases is not caused by improper disposal of sewage?

(a) cholera
(b) heart attack
(c) jaundice
(d) typhoid


(b) heart attack
Cholera, jaundice and typhoid are water-borne diseases. They are caused due to improper disposal of sewage.

Page No 241:

Question 2:

The solid matter produced during sewage treatment is

(a) slurry
(b) fertiliser
(c) sludge
(d) humus


The solid matter produced during sewage treatment is known as sludge.

Page No 241:

Question 3:

Which of these is a part of the wastewater treatment plant?

(a) clarifier
(b) vertical bars
(c) aeration tank
(d) all of them


(d) all of them
Clarifier, vertical bars and aeration tank - all of these are parts of a wastewater treatment plant.

Page No 241:

Question 4:

Which of these methods should NOT be used for disposal of urine and faeces if no sewage system is available?

(a) allowing untreated sewage to flow into rivers
(b) making septic tanks for sewage to flow into
(c) allowing sewage to flow into a biogas plant
(d) using a vermicomposting toilet


(a) allowing untreated sewage to flow into rivers

Disposal of untreated sewage directly into rivers can result in serious water pollution. This, in turn, can result in major health hazard for fish, birds, animals and humans. Polluted water is unsuitable for drinking, agriculture and industry.

Page No 242:

Question 1:

Stagnant water in blocked drains is a good breeding place for flies and ___________.


Stagnant water in blocked drains is a good breeding place for flies and mosquitoes.

Page No 242:

Question 2:

Domestic wastewater does not contain microorganisms. True of false?


False. Domestic sewage is likely to contain disease-causing microorganisms.

Page No 242:

Question 3:

Organic matter discharged into water bodies uses up substantial ___________ dissolved in water.


Organic matter discharged into water bodies uses up substantial oxygen dissolved in water.

Page No 242:

Question 4:

After proper sewage treatment, wastewater can be used for agriculture. True of false?


True. After proper sewage treatment, wastewater can be used for agriculture.

Page No 242:

Question 1:


Sewage is waste water generated from houses, industries, hospitals etc. It also includes rainwater that runs over land. It is carried away in sewers or drains.

Page No 242:

Question 2:

Why is it necessary to treat sewage before disposing it off in a water body?


Untreated sewage contains a wide variety of dissolved and suspended impurities. Hence, it is necessary to treat sewage before disposing it in a water body to remove its impurities and to prevent its devastating effect on humans, animals, fishes and birds.

Page No 242:

Question 3:

Name four diseases that can be used by an improper drainage system.


Cholera, typhoid, malaria and jaundice are four diseases that can be caused by an improper drainage system.

Page No 242:

Question 4:

Why is cholera outbreak common after floods?


During floods, huge amount of water comes down in a short time. Hence, water starts overflowing on the streets. The excess water then contaminates the drinking water supplies, bursts pipelines and causes sewers to reverse their course of flow. This leads to major health risks as excreta flows on the surface and contaminates the water. The contaminated water provides a breeding ground for the cholera bacteria. Hence, cholera outbreak is common after floods.

Page No 242:

Question 5:

In a city, there are separate pipes for disposing sewage and storm water. Why is this necessary?


There are separate pipes for disposing sewage and storm water because storm water infiltration into wastewater system can cause sewage overflow, which may lead to several environmental damages.

Page No 242:

Question 6:

What processes does sewage treatment involve?


Sewage treatment involves three processes, namely physical, chemical and biological. They remove physical, chemical and biological contaminants present in the wastewater.

Page No 242:

Question 7:

How can contamination of drinking water occur from sewage even in a covered drainage system?


In areas where drinking water pipe and sewage line are close, damages and leaks in the water pipe joints can sometimes lead to contamination of drinking water.

Page No 242:

Question 1:

List the ways in which wastewater present in sewage is generated and the kind of contaminants present in each.


Sewage wastewater includes:
(i) Waste water generated in houses during bathing, washing and cleaning kitchen utensils, which contains detergent and dirt as well as faeces and urine.
(ii) Wastewater generated in industries and hospitals, which contains poisonous chemicals.
(iii) Rainwater that has run down, which contains harmful substances.

Page No 242:

Question 2:

What problems can arise due to improper drainage?


Improper drainage can create unhygienic and unsanitary conditions in our neighbourhood. Open, dirty and stagnant water serves as breeding place for flies and mosquitoes. Sometimes, the river water and groundwater, which are sources of drinking water, get contaminated with human excreta and can spread water-borne diseases like cholera, typhoid etc.

Page No 242:

Question 3:

What dangers result from improper storm water drainage system in a city?


Improper storm drainage system in a city can lead to contamination of drinking water, bursting of pipelines and back flow of sewers. It is dangerous for public health and property. Contamination of drinking water can spread water-borne diseases like cholera, typhoid etc.

Page No 242:

Question 4:

Outline the main steps used in sewage treatment.


Following are the steps involved in the sewage treatment :
(i) The sewage entering into the sewage treatment plant is first passed through vertical bars to remove large rubbish objects like rags, sticks, cans, plastic bags etc.
(ii) Then the water is made to flow through settling tank. This is done to remove the grit and sand present in it.
(iii) The wastewater is then passed through the first sedimentation tank and allowed to stay there for a while.
(iv) The sludge is then taken out from the bottom and put into a large, closed tank called digester tank.
(v) The floating materials are removed by a skimmer.
(vi) The clarified water is then passed through the aeration tank, where aerobic bacteria consume or digest organic wastes such as human waste, food waste, soap and other unwanted materials.
(vii) From the aeration tank, treated water goes to the second sedimentation tank and allowed again to stay there for a while.
(viii) The treated water left in the second sedimentation tank has low level of organic materials and suspended impurities. The treated water is then released in the river.

Page No 242:

Question 5:

In what ways is the sludge obtained from a WWTP used?


The sludge obtained from a wastewater treatment plant (WWTP) is used as manure and biogas. The dried manure returns the nutrients to the soil, whereas biogas is used as a fuel.

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Question 6:

How can each one of us help in making the sewage treatment in our city more efficient?


Sewage treatment can be made more efficient by taking following precautions:
(i) Do not throw wastes such as solid food remains like tea leaves, sanitary towels, polythene bags, soft toys etc. down the drain.
(ii) Do not throw waste cooking oil and fat in kitchen sink as they can harden and block the drainage pipe.
(iii) Do not throw chemicals like paint, solvent, insecticides, medicines etc. in the drainage pipe.

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Question 7:

Mention three ways that can be used for sewage disposal if a proper sewage treatment plant is not available.


Followings are the three ways that can be used for sewage disposal if a proper sewage treatment plant is not available:
(i) Making septic tanks or septic tank toilets: It is suitable for places that have no sewerage system.
(ii) Making vermi-processing toilet: Here, the sewage is treated by earthworms in a pit. The earthworms gradually eat all the organic matters and decompose it.
(iii) Use of human excreta in biogas plants: Here, the human excreta from the toilet seats in the homes travels directly to biogas plants through covered drains.

Page No 242:

Question 1:

Which pipes should be bigger-those used for sewage disposal or those used for storm water disposal? Why?


The pipe used for storm water disposal should be bigger, i.e., it should have large diameter. This is because, when it rains very heavily, large amount of water comes down in a short time. If the diameter of the pipe is small, water will overflow on the streets and may cause major health risks by contaminating drinking water supplies.

Page No 242:

Question 2:

We realise that plastics, being non-biodegradable, are an environment hazard. However, while discussing the choking of sewage drains by plastics, why do we only talk about plastic carry bags and not of other plastic products?


In recent times, usage of plastic carry bags has increased at an alarming rate than other plastic products. Plastic carry bags are often thrown here and there. This clogs up gutters and drains and causes water and sewage to overflow in our homes and public areas.

Page No 243:

Question 1:

You go to the market and buy a toy. After coming home you remove the plastic packaging material in which the toy is wrapped, and throw it carelessly in a drain outside your home. What can be the result of your carelessness? What should you have done?


The plastic which has been thrown in the drain can block the drain or it can travel to a water body and harm the aquatic life.
The plastic could have been disposed in a safer manner or it may have been reused for some other purpose.

Part 2: Cracking the Circuits for Olfaction: Odors, Neurons, Genes and Behavior

00:00:00.00 Hi, I'm Cori Bargmann,
00:00:03.25 from the Rockefeller University in New York,
00:00:05.29 and the Howard Hughes Medical Institute.
00:00:08.02 And I'm going to talk today about work that we've been doing to try to crack circuits for olfaction,
00:00:13.27 to understand how you go from odors to neurons to genes to behavior.
00:00:19.24 Now, I'm going to talk about this in the context not of the noble human brain,
00:00:24.20 but of the noble brain of the nematode worm, Caenorhabditis elegans.
00:00:28.20 Why would we study a simple animal instead of studying humans?
00:00:31.29 The reason is that the human brain is almost unimaginably complex:
00:00:36.14 it has billions of neurons that are connected to each other by trillions of synapses.
00:00:42.03 By contrast, the nervous system of the nematode worm C. elegans has only 302 neurons
00:00:47.27 that are connected by 7000 synapses, and another 600 or so gap junctions.
00:00:54.15 Now, this much simpler nervous system nonetheless shares many components with the nervous system of a human.
00:01:01.19 So whereas humans have about 25,000 genes,
00:01:04.09 worms have about 20,000 genes,
00:01:06.09 many or which are shared between the species.
00:01:08.20 And when we look at the properties of the nervous system,
00:01:11.01 we find that many features of the nervous system are similar,
00:01:14.22 that worms use similar neurotransmitters, channels, and developmental genes, as humans.
00:01:20.07 Therefore, we think that some of the principles that underlie the function of the brain
00:01:24.08 and the function of brain circuits in behavior will also be similar between simpler animals like the worm
00:01:30.06 and complex animals like ourselves.
00:01:34.17 Now, with C. elegans, we also have, from the work of John White and his colleagues,
00:01:39.06 knowledge of how those 302 neurons communicate with each other, through a wiring diagram.
00:01:45.05 This wiring diagram contains only 6000 or 7000 connections,
00:01:48.26 but that's still too many, as you can see in this illustration,
00:01:52.24 to really understand the flow of information.
00:01:55.05 We need to directly test what the connections do,
00:01:57.28 we need to test what the neurons do, in order to understand behavior.
00:02:03.28 And the way that we try to understand behavior is using the behavior of the entire animal,
00:02:10.29 the functions of individual genes, and the functions of neurons,
00:02:14.18 and relate those to each other vertically, from the level of molecules
00:02:18.23 to the level of the entire organism.
00:02:21.07 Now, the starting point for this set of studies will be the fact that worms respond to odors
00:02:27.15 with robust behavioral responses,
00:02:29.24 that pose a set of questions we can ask about how behavior is generated.
00:02:33.24 So, if you put a lot of worms down in an environment where there's no odor,
00:02:36.27 they'll scatter around.
00:02:38.24 But if you them in an environment where there's a good odor on one side,
00:02:41.25 they'll quickly move to the source of that good odor and accumulate there.
00:02:46.29 Conversely, if you put them in an environment with a bad odor,
00:02:49.06 they'll go as far from it as they possibly can.
00:02:51.25 So we can see attraction, repulsion, or neutral responses in the behavior of the animal.
00:02:57.21 We can then ask: What parts of the worm brain are required for these different kinds of behaviors?
00:03:04.15 And we can ask this question through different kinds of approaches,
00:03:08.22 either loss-of-function approaches or gain-of-function approaches,
00:03:12.01 and both of those converge on the same answer,
00:03:15.03 which is that specific neurons detect odors and initiate behaviors in the animal,
00:03:20.20 and that the neurons that do this are reliably similar from worm to worm.
00:03:25.23 So, one way to determine that is to eliminate the functions of single neurons,
00:03:29.27 which we can do by killing them with a laser microbeam,
00:03:32.13 and when we do that, for example, for this neuron shown here in blue, the AWC neuron,
00:03:37.13 we find that the animals become defective in their ability to chemotax
00:03:40.26 to certain attractive odors and to search for food.
00:03:44.15 Now, if we kill the neuron right next to AWC, this red neuron, ASH,
00:03:48.20 there's no defect in odor chemotaxis and food search.
00:03:51.14 But now instead, there's a defect in nociception
00:03:55.16 and escape behavior that is triggered by noxious compounds that the worm hates.
00:04:00.20 So this tells us these neurons are required for different behaviors.
00:04:04.08 We can complement this loss-of-function analysis by gain-of-function analysis,
00:04:08.19 where we activate these neurons artificially and ask what behaviors the animal generates.
00:04:14.15 And the method that's used to do that currently in neuroscience
00:04:18.07 is to use a molecule called channelrhodopsin.
00:04:21.03 It's a light-activated ion channel from a unicellular organism.
00:04:25.23 The gene for channelrhodopsin can be introduced into different neurons in different animals,
00:04:30.25 and it will then make those neurons responsive to light,
00:04:33.15 so that when you shine light on them, the neurons become active.
00:04:36.15 You can then ask, in this gain-of-function configuration,
00:04:39.20 what happens when you activate one of these neurons?
00:04:42.26 And so for, example, as is shown in this movie here, when you activate the ASH
00:04:47.24 nociceptive neuron that mediates escape behaviors simply by turning a light on
00:04:52.26 and activating channelrhodopsin, the worm generates a reversal.
00:04:57.01 This is an escape behavior associated with a change of direction
00:05:00.16 that's exactly like what would happen if ASH detected one of its normal,
00:05:05.04 noxious stimuli that would also direct an escape behavior.
00:05:09.12 And so we can say here that ASH is both necessary and sufficient for generating escape behaviors.
00:05:18.13 Now, explaining escape behavior is pretty straightforward.
00:05:22.17 Escape behavior is deterministic
00:05:24.26 that means that, when a worm encounters a noxious substance,
00:05:28.09 as illustrated by this series of panels, every worm generates a reliable response
00:05:33.09 to that noxious substance, in a way that's quite predictable,
00:05:37.08 where it will back up, turn away, and move in a new direction.
00:05:41.04 But when we try to understand chemotaxis behavior, we see that it has different properties.
00:05:46.01 It's a probabilistic behavior,
00:05:48.08 and what I mean by that is that,
00:05:49.29 while all of the worms will eventually reach the odor,
00:05:53.12 they get to the odor by what seems to be an unpredictable path.
00:05:57.00 Every worm seems to follow a different path to reach the odor source.
00:06:01.09 How can we explain this more complex trajectory,
00:06:04.21 which doesn't look like the reflex or deterministic action?
00:06:07.26 What we need is some kind of a model that would explain
00:06:11.00 how animals can approach an odor.
00:06:13.29 And in fact, exactly such a model was developed by Shawn Lockery and colleagues,
00:06:19.05 and what they showed was that worms approach the odor using a strategy
00:06:24.01 called a "biased random walk," which is the same strategy that bacteria use
00:06:29.06 to detect attractive chemicals in their environment.
00:06:32.12 A biased random walk occurs through a fascinating strategy where
00:06:37.19 animals don't point their nose straight up toward the odor like a weather vane
00:06:42.11 instead, they simply move through their environment,
00:06:45.17 waiting to see whether conditions are changing, and if so,
00:06:51.05 whether they're getting better or worse.
00:06:53.18 And what the animals do is that they turn, changing directions,
00:06:56.29 at some constant rate in constant conditions.
00:06:59.25 But if conditions get better, if the odor increases,
00:07:05.23 then they make fewer turns.
00:07:08.04 If the conditions get worse, if the odor decreases,
00:07:11.12 they make more turns.
00:07:12.27 And the effect of this, is that animals will move in a good direction
00:07:17.00 where odors are increasing for a longer period of time,
00:07:21.04 and they'll move in a bad direction where odors are decreasing
00:07:24.00 for shorter periods of time.
00:07:25.20 And eventually, just changing direction at random,
00:07:28.15 this will lead them to accumulate at the odor through what appears to be a
00:07:32.13 more-or-less random path.
00:07:34.14 So the key feature of this strategy is that the animals aren't detecting the absolute levels of odors,
00:07:40.01 they're detecting the change in an odor level.
00:07:42.27 are things getting better or are things getting worse?
00:07:46.03 They're looking at the change in concentration over time.
00:07:51.05 So, we would like to test this model.
00:07:53.14 How do you go about testing a model like this, about odor concentrations over time?
00:07:58.20 The way you have to test this model is to generate a temporal gradient,
00:08:03.12 an odor environment that changes only over time and not over space,
00:08:08.12 to test the predictions of this particular quantitative model.
00:08:12.13 And the way that this can be done is by generating small chambers
00:08:16.11 in which animals can be exposed to odors flowing past them rapidly,
00:08:20.13 and then examine for their different kinds of behavioral responses.
00:08:24.07 And a chamber to carry out this task was designed by Dirk Albrecht.
00:08:30.05 So, what Dirk did was to find a small environment in which he could provide pulses of odors
00:08:35.20 at a known concentration at a known schedule,
00:08:38.10 and examine the responses of the worms in these environments.
00:08:41.23 And as is seen in the movie here, when you watch worms moving through this chamber,
00:08:46.02 sometimes they move in straight lines, and sometimes they change directions,
00:08:49.11 generating different kinds of turns.
00:08:51.28 Now, this light color here are worms in the absence of an odor.
00:08:55.12 Some of them are turning, some of them are moving in straight lines.
00:08:58.07 When the dark color appears, that will signal the appearance of an attractive odor.
00:09:02.25 When the light colors appears, the odor will disappear.
00:09:05.25 And what you should be able to see is that,
00:09:07.17 when the odor appears, the worms move in long, straight lines,
00:09:11.08 and when the odor disappears, they turn, they change direction.
00:09:15.02 Again, attractive odor. long, straight lines.
00:09:18.28 Disappearance. turning.
00:09:21.13 This is exactly the behavior that is predicted in the biased random walk model:
00:09:26.22 An increase of turning when conditions are getting worse.
00:09:30.14 So here we can see that at a visual level.
00:09:33.05 But in order to understand behaviors, we need to quantify those behaviors,
00:09:37.08 not just look at them qualitatively.
00:09:40.16 And to do that, we can use methods to automatically analyze the turning behaviors
00:09:45.08 using computers to monitor the position of worms over time.
00:09:49.04 We can then assign to each of the worms a description of what it's doing at any particular time:
00:09:54.23 Is it moving forward, here in gray?
00:09:57.02 Is it pausing or reversing, here in black?
00:09:59.24 Or is it generating different kinds of turns, called pirouettes, here in red?
00:10:04.17 This analysis can be done for many hundreds of animals over different kinds of stimulus protocols,
00:10:10.20 leading to the kinds of data shown here, where animals are exposed to pulses of odors in blue,
00:10:17.25 and odor being removed (replaced by buffer) in white.
00:10:21.25 And then here, hundreds of animals are monitored for their behavior in response
00:10:26.04 to that sequence of odor and buffer pulses.
00:10:29.04 Now what you should be able to see is that there's a lot of red and black material in the presence of buffer,
00:10:34.26 but much less when odor is present.
00:10:38.04 These hundreds of traces can then be quantified to generate the one trace underneath,
00:10:42.29 which shows the probability of turning under different conditions.
00:10:47.12 And what you can see is that, when odor is present, as it is here,
00:10:51.08 the probability of turning is quite low, but it's not zero.
00:10:55.04 And when odor is removed, as is shown here,
00:10:57.17 the probability of turning shoots up, but it doesn't go up to 100%.
00:11:02.03 it eventually returns again to the basal probability of turning.
00:11:06.11 So from this we can say a couple of different things:
00:11:08.29 We can confirm the biased random walk model, we can say that, yes,
00:11:12.14 turning rates do change based on odor history,
00:11:16.01 whether odor has been added or removed.
00:11:19.02 And we can also notice that this is indeed a probabilistic behavior,
00:11:23.29 that the probability of turning changes, but it's never 0%, and it's never 100%.
00:11:29.19 To understand behavior, we have to think quantitatively and statistically
00:11:33.28 about what animals are doing at any given time.
00:11:39.17 So, using these kinds of assays and simpler assay that resemble these,
00:11:44.09 it's been possible to map out neurons that are required for odor chemotaxis and food search.
00:11:50.18 I told you that the AWC neuron, an olfactory neuron, is required for odor detection.
00:11:55.23 AWC forms synapses onto three different classes of interneurons,
00:12:00.16 neurons that collect information from a variety of sensory neurons,
00:12:04.23 and these neurons are connected to each other and with a fourth neuron.
00:12:09.04 All four of these neurons, that are one synapse away from the AWC neuron,
00:12:13.26 regulate turning probabilities.
00:12:16.15 Two of them, shown in blue,
00:12:18.15 act to increase the rate of turning when odor is removed, and two of them, show in red,
00:12:24.09 act to decrease the the rate of turning.
00:12:26.14 So they're both positive and negative signals in this circuit that are mediating odor information.
00:12:32.27 Now, once a turn is being generated,
00:12:36.08 the worm has to decide what kind of turn it's going to be.
00:12:39.00 The neurons shown here in gray at the bottom of the slide
00:12:42.02 are neurons that help interpret this turning frequency information and
00:12:45.19 turn it into different kinds of output motor behaviors.
00:12:48.22 I won't talk about those further in this talk.
00:12:51.02 I'll just concentrate on the first step:
00:12:53.08 How is the problem of detecting odor transformed through the neurons
00:12:57.11 that collect this information from the sensory neuron, to regulate turning rates?
00:13:04.28 So, one way to answer that question is to start to get a dynamic picture
00:13:09.18 of what the neurons are doing in response to odors.
00:13:13.10 We want to visualize what's happening in these neurons.
00:13:16.21 So what are the tools we can use to understand when neurons are active?
00:13:20.25 In C. elegans, one of the tools we like to use are genetically encoded calcium indicators.
00:13:27.23 These are fluorescent proteins based on the "green fluorescent protein"
00:13:32.05 that include within them a calcium-binding protein "calmodulin,"
00:13:35.29 as well as a peptide that will bind to calmodulin when calcium is present.
00:13:40.25 Through genetic engineering and biochemical studies,
00:13:43.13 Junichi Nakai and others have generated versions of these proteins that increase fluorescence
00:13:49.06 when they are bound to calcium, and are less fluorescent when they are not bound to calcium.
00:13:53.28 This is useful to us because calcium is a good reporter of when a neuron is active.
00:13:59.20 When neurons are depolarized, they open voltage-gated calcium channels,
00:14:04.07 leading to an increase of calcium within the cell.
00:14:07.03 And therefore, an increase in fluorescence of a protein associated with
00:14:11.07 an increase of calcium will tell you when a neuron is depolarized.
00:14:16.04 To monitor a specific neuron,
00:14:17.27 we then take advantage of the powerful transgenic tools in C. elegans
00:14:22.04 to express this genetically encoded fluorescent protein
00:14:25.02 only in a single kind of neuron of interest,
00:14:27.23 in this case, in the AWC neuron, to ask when that neuron is active.
00:14:35.20 Now there's a third component required to monitor the activity of these neurons,
00:14:39.22 and that is that we need to be able to hold the worm still and
00:14:42.29 deliver odors in precise patterns while monitoring the fluorescence intensity of the AWC neuron.
00:14:50.05 We do that by borrowing a technology back from the engineering,
00:14:54.05 from the silicon chip, industry, into biology, called microfabrication.
00:14:58.23 And we build special worm traps that are worm dimension,
00:15:02.21 that enable us to hold a worm in an optically transparent environment,
00:15:07.23 while restraining it in three dimensions, and then flowing different kinds of fluids
00:15:11.20 past the nose of the worm while monitoring fluorescence intensity.
00:15:15.12 This microfluidic chamber then permits us to combine the genetic tools
00:15:20.00 with chemical tools to monitor neural activity.
00:15:25.13 And that's exactly what's happening in this image here.
00:15:28.17 So this is a single AWC neuron expressing a genetically encoded calcium indicator,
00:15:33.20 and you will see when the movie starts, the neuron starts with a yellow level of fluorescence
00:15:39.05 and a relatively low level of fluorescence in the process of the neuron.
00:15:42.26 Ten seconds into the movie, a switch in odor stimuli will occur, and the neuron will become brighter.
00:15:49.22 The brighter color, the more intense color, the larger white color in the cell body of the neuron over here,
00:15:54.21 all reflect the fact that calcium has gone up, and the neuron has become active.
00:15:59.17 So, indeed, we can see that the AWC neuron responds to odors by changing its activity.
00:16:06.23 But it responds in a way that we did not expect,
00:16:10.06 because the AWC neurons are not activated when odors are presented to the worm.
00:16:15.26 In fact, when we look at the fluorescence intensity and graph it in the presence of odor,
00:16:20.05 it is, if anything, a little less intense than it would have been in the absence of odor.
00:16:26.27 Instead, the AWC neurons become active when odor is removed.
00:16:31.21 This leads to a large increase in the fluorescence intensity,
00:16:34.21 indicating depolarization and the presence of calcium.
00:16:38.08 So these neurons seem to work in reverse.
00:16:41.13 They are inhibited by odors, their natural stimuli.
00:16:44.28 They are active when odors are removed.
00:16:47.24 And I just want to remind you that the worm has to generate a behavior when odor is removed.
00:16:53.02 When odor is removed, the worm is going to start turning.
00:16:56.00 So the activity of the neuron is correlated with the behavioral output, not with the input stimulus.
00:17:05.18 So we can now say something about this first neuron that interacts with odors.
00:17:10.25 How does it communicate with the target neurons that then convert this information into behavior?
00:17:17.10 The way that we study this is by studying the process of synaptic transmission.
00:17:21.15 Neurons connect to each other at specialized structures called synapses,
00:17:25.08 where a presynaptic neuron, the upstream neuron, in this case AWC,
00:17:29.28 will release vesicles filled with a neurotransmitter, and these neurotransmitters
00:17:33.24 will interact with receptors on the postsynaptic neuron, here shown in gray.
00:17:39.01 One kind of neurotransmitter that neurons release is glutamate, an amino acid,
00:17:45.25 and glutamate is packaged into special synaptic vesicles by a molecule called the
00:17:49.25 "vesicular glutamate transporter," or EAT-4 in C. elegans.
00:17:54.25 We can use this EAT-4 molecule to probe the action of synapses in the AWC neuron.
00:18:02.27 We can do that by using mutants in EAT-4 to inactivate the transporter
00:18:07.26 and therefore the ability of AWC to release glutamate.
00:18:11.19 And we can ask then,
00:18:13.09 what kinds of behavior can the animal generate in the absence of this glutamate transmitter?
00:18:18.15 And remember that turning is a reflection of the response to odor removal,
00:18:23.22 an important component of chemotaxis behavior, and that we can quantify this.
00:18:26.27 So a high level here of "1" is a high level of turning.
00:18:31.13 In red here is an eat-4 mutant.
00:18:33.15 The eat-4 mutant does not turn efficiently when odor is removed,
00:18:37.21 indicating to us that glutamate is required as a neurotransmitter for this turning behavior.
00:18:43.04 And when we restore EAT-4 just in the AWC neurons using a specific transgene,
00:18:48.22 we restore most of the turning behavior.
00:18:51.01 And so we can say that glutamate from AWC promotes turning.
00:18:57.25 So we now have insight into the first step of how AWC communicates with its target:
00:19:03.10 It uses EAT-4 to package glutamate into vesicles, it releases glutamate,
00:19:08.06 and this must then act on target neurons.
00:19:10.23 How does it communicate with the target neurons?
00:19:12.26 How does it communicate with these three different neurons with which it forms connections?
00:19:17.00 Well, it has to do that through glutamate receptors,
00:19:20.04 proteins that are expressed on the target neurons that enable them to detect the released glutamate.
00:19:25.11 And we found that there are two classes of glutamate receptors
00:19:28.22 that are important for this particular behavior.
00:19:31.29 There's a glutamate-gated cation channel it's an excitatory receptor called GLR-1.
00:19:38.01 And there's also a glutamate-gated chloride channel,
00:19:41.05 an anion channel that is an inhibitory receptor called GLC-3.
00:19:45.14 These two glutamate receptors,
00:19:47.11 which can generate two different kinds of responses in target neurons,
00:19:50.20 are important for AWC's communcation with its targets.
00:19:56.26 We can demonstrate that both through quantitative behavioral assays
00:20:02.18 and through direct observation of the activity of target neurons,
00:20:06.18 which we do using genetically encoded calcium indicators.
00:20:10.15 Now, instead of expressing them in AWC, we express them in downstream neurons,
00:20:15.24 such as AIB.
00:20:17.18 AIB is one of the neurons that receives synapses from AWC,
00:20:21.16 and we see that AIB, like AWC, responds to odor removal by an increase in calcium.
00:20:29.06 This response disappears if the AWC neuron is killed,
00:20:33.21 and it also disappears in an animal that lacks the glutamate receptor GLR-1.
00:20:38.17 GLR-1 is required in AIB for AIB to sense the glutamate signal from AWC.
00:20:46.09 This excitatory glutamate receptor transmits an excitatory signal from sensory neuron to interneuron.
00:20:56.03 Next, we looked at the AIA and AIY interneurons.
00:21:01.09 These neurons also respond to odors,
00:21:04.05 but these neurons respond oppositely to AWC.
00:21:08.12 AIA and AIY respond with an increase in calcium to odor addition,
00:21:13.22 there's been a change in the sign of the signal between the sensory neuron and the interneuron.
00:21:18.21 They don't respond to odor removal.
00:21:21.19 Now this response to odor addition still requires AWC,
00:21:25.19 and it requires a glutamate receptor.
00:21:28.04 It requires GLC-3, the glutamate-gated chloride channel.
00:21:32.21 This inhibitory receptor serves to transmit a signal from an excited AWC
00:21:38.18 into a signal that will inhibit the downstream neurons,
00:21:42.06 so the downstream neurons AIA and AIY respond oppositely
00:21:47.00 to odors than the upstream neuron AWC.
00:21:52.24 So putting this information together, here on the left,
00:21:56.09 we can assemble a C. elegans odor circuit.
00:21:59.26 We can say that attractive odors inhibit the AWC olfactory neurons,
00:22:04.16 that the AWC olfactory neurons now release glutamate
00:22:08.03 onto two classes of downstream neurons through two classes of receptors.
00:22:12.16 They excite one class of neurons, the AIB neurons,
00:22:15.25 through an excitatory glutamate receptor.
00:22:18.14 They inhibit other classes of neurons, AIA and AIY neurons,
00:22:22.17 through an inhibitory glutamate receptor.
00:22:25.15 By splitting the information in this way,
00:22:27.15 the AWC neurons have now transformed information into two streams:
00:22:32.00 One signals the appearance of odor, an "odor ON" response
00:22:35.17 the second stream signals the disappearance of odor, an "odor OFF" response.
00:22:40.26 Remarkably, when we examine this circuit,
00:22:43.12 it looks similar to another sensory circuit that's been well characterized,
00:22:47.14 and that is the circuit that is used to collect light in the vertebrate retina,
00:22:51.18 in your own eye.
00:22:53.14 So in your eye, light is collected by the rod and cone photoreceptors.
00:22:58.15 Rods and cones are active in the dark
00:23:00.29 they are inhibited by light, their natural stimulus,
00:23:04.03 just as AWC neurons are inhibited by odors.
00:23:08.12 Rods and cones release glutamate to communicate with their targets,
00:23:12.04 and they have two major classes of target neurons.
00:23:14.28 The target neurons are called bipolar cells.
00:23:17.24 One connection is through an excitatory glutamate receptor, and therefore,
00:23:22.24 these neurons have the same pattern of activity as the photoreceptors.
00:23:27.01 They're what are called "OFF" bipolar cells they signal when lights go off.
00:23:31.26 The other class of neurons are connected through inhibitory glutamate receptors.
00:23:36.01 Therefore, these neurons are called "ON" bipolar cells they signal when lights come on.
00:23:43.05 So comparing these different neural circuits,
00:23:45.19 we can say that in a worm olfactory system and in a vertebrate visual system,
00:23:50.23 some of the same principles are used to process sensory information.
00:23:55.02 Differential signaling of the appearance and the disappearance of a stimulus,
00:23:59.16 differential signaling through different classes of glutamate receptors,
00:24:03.01 to split information through different circuits.
00:24:05.22 This kind of insight helps convince us that there may be principles
00:24:09.10 for neural circuits that apply across different systems,
00:24:12.16 that will help us understand information processing.
00:24:16.01 What I've told you is that AWC communicates with three downstream neurons,
00:24:20.19 using glutamate to send complex information about the input stimulus
00:24:24.25 to different downstream sets.
00:24:28.23 In addition, AWC has another way of communicating with its targets,
00:24:33.04 because AWC doesn't just release glutamate,
00:24:35.23 it releases a second transmitter, a neuropeptide neurotransmitter called NLP-1.
00:24:41.15 NLP-1 is related to neuropeptides called buccalin in other animals,
00:24:46.02 and NLP-1 signals through a G protein-coupled receptor, called NPR-11.
00:24:52.04 NPR-11 is expressed on some of the downstream neurons from AWC,
00:24:57.18 but not all, including the AIA neurons.
00:25:01.09 So glutamate is released from AWC onto several neurons, and in addition,
00:25:05.29 a neuropeptide is released from AWC onto a subset of those neurons.
00:25:12.29 What is the function of NLP-1?
00:25:15.18 We can ask that by examining animals that are mutant for the NLP-1 neuropeptide
00:25:21.00 or mutant for its receptor,
00:25:22.27 and then comparing their behaviors to the behaviors of wild-type animals.
00:25:27.13 And what we find is that the function of NLP-1 is to antagonize
00:25:32.17 the glutamate signal from the same AWC neuron.
00:25:36.17 So, this is illustrated here in the quantitative turning behaviors that measure AWC output.
00:25:42.11 So a wild-type animal, shown here in white,
00:25:44.29 will turn about once a minute in response to odor removal.
00:25:48.22 These turns are absolutely dependent on the glutamate signal from AWC.
00:25:52.29 There are simply no turns when AWC glutamate is absent, as shown by this mutant.
00:26:00.06 But when we look at the nlp-1 mutant, we see that there are turns.
00:26:03.25 In fact, there are more turns than there would be in a wild-type animal.
00:26:07.21 So AWC is both sending a signal to stimulate turning (the glutamate signal),
00:26:12.20 and it's sending a second signal that inhibits turning (the NLP-1 signal).
00:26:17.23 It's limiting its own output by generating these two antagonistic signals.
00:26:24.08 We next asked how this signal interacts with the circuit
00:26:29.12 to affect the activity of different neurons.
00:26:32.20 And here there was a large surprise.
00:26:35.14 So we examined the nlp-1 mutant, and mutants in its receptor NPR-11,
00:26:40.17 to see where activity in the circuit was changed compared to the activity of wild-type animals.
00:26:45.25 We saw changes in the activity of the neurons not just in downstream target neurons
00:26:51.16 we saw changes in AWC itself.
00:26:54.23 The olfactory neuron responds differently to odors
00:26:58.01 depending on the activity of this peptide system.
00:27:01.21 So we can see this here in calcium imaging experiments showing
00:27:05.08 the response of AWC neurons to odor removal.
00:27:08.23 In wild-type, they show a sharp, short response.
00:27:12.06 In animals that lack the NLP-1 peptide or its receptors,
00:27:16.27 we instead see a longer-lasting response and repeated responses,
00:27:20.21 indicating that the AWC neuron is staying active for longer after odor has been removed.
00:27:28.17 Now, AWC is releasing this signal, the receptor for this signal in on a downstream neuron.
00:27:34.23 How does that information come back to AWC?
00:27:38.15 The answer is that the downstream neuron releases another signal, a feedback signal,
00:27:44.20 that is an insulin-like peptide, that returns to the AWC neuron to modify its activity.
00:27:50.26 So, a signal from AWC talks to a target neuron,
00:27:54.07 the target neuron then sends a signal back to AWC,
00:27:57.13 and again, the use of that signal limits the activity of the AWC neuron.
00:28:02.12 The feedback keeps AWC from generating these longer
00:28:06.03 or repetitive responses to odor removal.
00:28:11.29 So, it seems curious that a neuron would be generating
00:28:14.21 both positive and negative responses.
00:28:16.29 What could be the purpose of generating a negative feedback signal?
00:28:21.13 To understand this, you should understand that,
00:28:24.02 in animals, odor preference is modified by its experience with odor.
00:28:28.10 And this can be illustrated in a variety of ways,
00:28:31.15 but one simple way is that, when animals are exposed to odor in the absence of food,
00:28:35.25 they slowly adapt to the odor, so that they are no longer attracted to it.
00:28:40.15 This causes animals to prefer new odors,
00:28:43.18 or odors that have been paired with food,
00:28:45.14 to odors that have been seen in the absence of food,
00:28:49.02 and it represents an obvious good behavioral strategy for finding odors
00:28:53.11 that might be predictive of food in the future.
00:28:56.00 This can be quantified here, where the attraction to odor, shown here in black,
00:28:59.22 drops after 60 minutes of seeing an odor without food,
00:29:03.04 and drops even further after two hours of seeing the odor without food.
00:29:09.03 This change in the odor-dependent activity requires the neuropeptide feedback loop
00:29:16.10 that limits AWC activity.
00:29:19.06 If you remove either NLP-1 or its receptor NPR-11
00:29:24.13 or the feedback signal INS-1 that converts that information back to AWC,
00:29:29.19 then animals that have been exposed to odor, adapted animals, as shown here,
00:29:34.05 continue to respond to odor even after a long time of pairing of odor at the absence of food,
00:29:40.07 where wild-type animals would lose their response.
00:29:44.09 Adaptation requires the function of NLP-1 in the AWC neurons
00:29:49.22 and the function of NPR-11 and of INS-1 (the feedback signal) in the AIA neurons.
00:29:56.04 And so we can map this particular negative feedback signal to a particular
00:30:01.09 negative feedback that must occur to drive a useful olfactory behavior:
00:30:06.10 olfactory adaptation.
00:30:09.14 The activity of this feedback loop is observed not only at the behavioral level,
00:30:13.23 but also at the level of neuronal responses,
00:30:17.01 because when we examine the activity of AWC neurons after a long time of exposure to high odor,
00:30:23.06 as shown here in black, they simply stop responding to the odor
00:30:27.17 if the odor was present in the absence of food.
00:30:30.26 And this suppression of their response is defective in animals
00:30:36.05 that lack the neuropeptide feedback signal, as shown here in red,
00:30:39.29 which continue to respond to the odor even when it no longer predicts the presence of food.
00:30:50.07 So the conclusion of this part of the talk is that neuropeptide feedback,
00:30:55.04 superimposed on the basic function of the circuit, shapes sensory dynamics:
00:31:01.06 That sensory neurons like AWC respond to odors not in one way,
00:31:05.17 but in different ways depending on the activity of a feedback circuit
00:31:09.20 that if that feedback circuit is lost, the sensory neurons respond for longer and with multiple stimuli
00:31:16.14 that if the feedback circuit is present, they respond with a short stimulus
00:31:20.07 and that if the feedback circuit is strongly activated through olfactory adaptation,
00:31:24.25 the sensory neurons stop responding,
00:31:26.23 allowing the animals to suppress the response to that odor, and to respond to new odors.
00:31:34.08 And the conclusion of this talk is that circuits change over time, that circuits are not fixed,
00:31:41.09 that they actively shape and transform sensory information.
00:31:45.05 They don't just passively receive that information.
00:31:48.03 And furthermore, circuits change their own properties
00:31:51.05 based on sensory information in real time.
00:31:55.12 This process, this dynamic and active interpretation of information,
00:32:00.18 allows circuits to perform complex computations and calculations.
00:32:05.14 If you take just what I told you about this small circuit of just a few C. elegans neurons,
00:32:11.06 you can realize that, if you multiply that by the billions of neurons in a human brain,
00:32:15.21 it can start to explain why a human brain can generate an
00:32:19.17 infinite number of perceptions, memories, and behaviors.
00:32:23.18 Thank you.

  • Part 1: Genes, the Brain and Behavior

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Earthworms Taking Over Driveway

After a rain, or when humidity is high, it’s very common to see earthworms making their way to the surface of the earth, including driveways and sidewalks. Earthworms breathe through their skin (they don’t have lungs), and they require a balanced level of moisture in order to survive.

When the soil is too dry, they burrow deeper to find moisture. When the soil is wet, they move closer to the surface. When there is adequate surface moisture or humidity, they venture out aboveground and look for new places to burrow. The wet weather of spring and fall seems to bring them out in droves.

Earthworms are one of those mixed blessings in the yard and garden. One acre of healthy soil can have as many as a million earthworms!

It’s GOOD to have earthworms – they aerate and enrich the soil, move nutrients around, digest and break down organic matter, and improve drainage and soil texture. In fact, earthworms do a better job than any farm or garden practice, and the gardener gets to reap the benefits.

However, the downside of having a healthy earthworm population is that they are constantly underfoot during wet weather.

Because earthworms are considered beneficial creatures, most pest-control products have been designed not to harm them. There are currently no products specifically for controlling earthworms, and it’s really not recommended to try to kill them at all.

So, the problem of earthworms on the driveway is one that we have to learn to live with (by stepping over them, or sweeping or rinsing them off), rather than control. Inviting more birds to your yard may help – I have several large robins in my yard that are constantly gorging at the earthworm buffet, and I’ve never seen a worm left behind.


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Why would this happen when the weather is dry? I went outside this morning to find the drive, sidewalk, and street covered in worm jerky. My neighbors drives and sidewalks are also affected.

I’m used to seeing this after a rain. I’ve never seen it without rain nor have I seen such a number of the poor little creatures.

Thanks for any info you can share,

Like Leslie, I too had the same occurrence with the earthworms this morning. When I went outside at 6:30 AM there were hundreds of worms all over my driveway and sidewalks, as well as those of all my neighbors. My property seemed to have the most though, but the worms were spread all around the cul-de-sac I live on. If you have any idea on what happened, please let me know. Thank you very much.

Three weeks ago we had our driveway dug up and repaved with tar. We now are noticing earthworms in our driveway something we never had before. Could this be the reason. Were they disturbed? Hopefully you can answer this for us. Is there a way we can rid of them. Thanks so much.

how do you get the worms out of the ground ?

Ive lived in my home for 22 yrs . this is the first yr that the earthworms hav come out in thousand after every rain. its amazing they form balls of hundreds if not thousands. They climb the garage doors and fill the spaces. Ive never seen so many at one time in my life. They are all around my house afetr the rain. They seem not to go back in the ground but dry up and die. You would think they would then lessen in numbers but they have increased with every rain. I dont use chemicals on my property so I dont get whats going on. It seems it might be a health hazard and would like some advice how to stop this occuance

I used to see many earthworms in my driveway after a heavy rain. I no longer see any earthworms and wonder why. Any answers?

we have had lots of rain in north carolina this year . This morning I went out to get the news paper and there were hundrens if not thousands of dead earthworms in the driveway. I guess I will get the blower and blow them of the drive.

I recently found 100s of earth worms on paved drive way. Either dead or dieing. I have lived in NC all of my life and have never seen this occurrence. I thought and still maybe think something is going on.
A week later near my neighborhood at night while walking I came across 100s of centipedes crawling but still alive. I have never seen that many at once. I just wonder if it means something. Maybe, earth quake? curious.

We live in NC also and I am seeing the dead worms in my driveway after a rain and without rain. My neighbor up the hill does water his lawn most evening, so I assume that is why. I am wondering if planting some bushes on the edge of the driveway will prevent them from crawling to the driveway?

We have seen a lot of dead worms on the driveway especially after rains. We have never seen this before and we bit worried about it. Is there anything that can be done? North Carolina

I have lived here on a slab for 6 months, Pittsboro, NC lived in Southport, NC (3 1/2 hrs south)& never had these problems…Just working on an ant infestation & now I wake up to hundred of earthworms all along both garage doors. What do I do to get rid of them permanently? I can’t stand all these issues. Do tell me what to expect spring/summer. Thank you.

I don’t believe what i have are earthworms because they have a deep brown color and when you step on them they now excrete a greenish black then is very hard to sweep away. They only look to be about an inch long. They come out at night and love to hide under anything that is dark such as cars and pots and etc. They also like the patio and driveway. Please respond to this site or email me at [email protected] I am going bugging.

I would think that the birds would have a feast on our driveway when this happens but not a one is eaten? Even the crow who would seemingly eat anything can’t be bothered?

Here in East Texas, we too, are having an explosion of driveway earthworm sightings in the morning hours. Reading your explanation of increased movement to the surface during periods of high humidity does seem to help me understand why so many more are surfacing. We have had very humid conditions this spring and early summer. I am sure my neighbors would die laughing (or worse!) if they knew I often spend 5 minutes in the morning mumbling “Save the earthworms!” as I try to “rescue” those poor guys that still show signs of life from an untimely concrete baking.

I’m here in Macon GA and the worm invasion on the driveway this morning was massive. I don’t understand, I’ve lived in this house 12 years and have never had a worm issue. It’s just so many it’s gross. I too have tried to rescue some to the front yard but way too many today. HELP…any ideas.

It’s nice to see the questions as we’ve had this problem…but WHERE ARE THE ANSWERS.

Hi Lee,
If by answer you mean the solution to keeping earthworms off your driveway, you could try installing solid edging around the sides of your driveway that sticks up a few inches higher than the ground to provide a barrier to earthworms. To find out more about landscape borders and lawn edging, go to

Out of the the houses on my block my house is the only one that’s got this issue. Maybe I’m cursed.

We are they only house on our block to have this happen. We are also the only house to have our yard aerated in the Spring. However it happen this morning September 21st. CRAAZZZZYYY!

We have a huge problem with earthworms this year in Northern California due to high amount of early rains. However, I’m most puzzled by the fact that these (2 kinds: small – about 1″ or less & large, common, brown) earthworms not only occupy the driveway but try to get inside the house. Every time there’s a heavy rain I have to sweep hundreds of (mostly the smaller black ones) off the threshold, between the screen door & main doors. I understand all that has been said in this thread about their movements, etc. but why are they coming inside.

We often keep the main door open during the day (despite the rain.. it’s CA so it’s quite warm).. and I have to literally sweep them off the indoor carpet! Arghhhhh. I hate creepy crawlies IN THE HOUSE. Still, I’m loth to kill these as they’re beneficial to the soil, but come on… they are not welcome inside!

I can’t stop wondering why are they even heading indoors, towards the warmth, when there’s an empty parcel next to our house, a driveway & then small wedge of soil (with a fig tree) on the other side of drive. I really can’t understand this & it’s extremely annoying – even more so because I’m disabled & sweeping them is no light task for me.

Unfortunately, I don’t have capabilities to hose them off.. and anyway, how to that when for example I found one way inside the house today, crawling on the [berber] carpet.. and dozens on the aforementioned threshold. If it was just one or even a few – I’d think they’re lost, but this is happening repeatedly DURING – NOT AFTER – each HEAVY rain this fall (light rain = no earthworms!).

This might be a silly question, but could they be drawn to the smell of cat food, which is kept near the door?

Any advice how to keep them from coming indoors would be much appreciated, thanks!

We have found a way to rid this worm problem. You can either use salt to put in the cracks or put salt directly on them. It kills them instantly. Or you can put full strength bleach in your sprayer and just spray all around your carport. It kills them instantly also. We get them every year. I mean we have millions of them and poof they’re gone.

Tonight I was walking through my yard and must’ve seen thousands of worms throughout the entire lawn. I’ve never seen anything like it. I live in the Midwest (Illinois) and I even joked tonight about charging people by the hour to come fill buckets for fishing bait. Every step I took I would see dozens more. Is this normal or have I gone clinically insane?

My husbands mountain cur dog take great delight in eating worm jerky baked by the hot sun, bleh, yuck to us… Breeds said she’s craving protein perhaps…well it’s cheaper than expensive scientific engineered dog food.

I want to have millions of earth worms! I want to harvest them to bring to my chickens! How can I get that to happen? I live in N.W. Oregon and it rains quite a bit, but I have not had the bounty some of the writers below are experiencing. We have lots of land that is just good earth. I have a few compost bins. Maybe there are worms in them! I want to set it up so there are LOTS! Where could I find more data on how to get a lot regularly?

Seriously? I’m surprised that after scrollin’ for days… Just gave up to add my 2 cents.

At least SOMEone should’ve mentioned pesticides. Not one person on here has had their yard sprayed… And observed the same day is probably when the worms have emerged, usually after running the sprinkler system.

They were fine at some point before… What’s changed? It seems we have yet another case of selective consideration and ignorance. Juuuuust pointing out the truth it isn’t practical to merely point out a problem without gesturing to a form of a solution.

LOL! This is such a weird and condescending comment! At least learn how to write properly if you are going to play the condescending Mum!

I also have that problem. I pour a line of salt along my porch & driveway. They die when they touch the salt. I know they are animals blah blah blah but it’s disgusting!

I would have to consider the possibility of more pollutants/acid/base in the rain, which poisons the worms. They come to the surface and try to escape, only to dry up and die in the process.

I hate worms, they may be great for healthy soil, and a delight for birds and cats, just stay out of my way…salt is the solution for me. i sprinkle salt to keep them out of my site, that kills them also

I have lots of earthworms on my driveway after it rains. I looked at all my neighbors driveways and they don’t have earthworms on theirs, while mine is covered with them. My driveway is the only one in the neighborhood with earthworms littering it. I live in Florida, and summer is our rainy season. It rains nearly every day during the summers. We get rain intermittently during the other times of the year. I have noticed that the worms do not come on to the driveway during the summer months, even with the daily rains. It is only during the fall, winter, and spring months that they do. I have racked my brain to find the cause. My current theory is that the worms are attracted to the driveway by Clorox. I believe I am the only person in the neighborhood who uses Clorox to clean the driveway. For some reason, I believe, the worms are attracted to an ingredient in Clorox. I am also confirmed in that theory by a similar problem my brother has. Only, it is his swimming pool that the worms invade when it rains. Could it be the chlorine that is attracting earthworms?

I have many worms on my driveway which runs all around the house. I have never seen this before and am worried they might get onto my puppy which I have recently bought. How do I get rid of these worms they are coming through the tarmac around the house.

I get lots of earthworms on my driveway when it rains. Huge nightcrawlers., small ones, all sizes. I either pick them up with my hand or carefully brush them into a dustpan and then move them to the center of the lawn. They are beneficial to your lawn, so why are many of you wanting to kill them? The worms were there before you were, so let them live.

It’s a myth that earthworms are good for the soil. Get some nice soil. Put it two big flower pots. Put lots of earthworms in one and make sure none get in the other. In fall when you pour out the soil, the one with earthworms will,have big hard lumps of dirt. The other soil will be loose. Earthworms eat the organic materials and leave the clay. I hate them. I have forty years of experience with earthworms. They destroy perennial flower beds in about five years. And I have to continuously add new good soil to my vegetable garden. My gardening neighbours will tell you the same thing. Maybe some species of earthworms are okay. But if you would like some for your garden, I can certainly supply them. I pick them them and drown them.

I have the same problem on Houston on a patio. It is absolutely disgusting. Had to throw away a patio rug. Used chlorax spray, and will try salt. Worms are not critical as most of the area is concrete/pool landscaped. It must have to do with the mulch or soil below. Extremely grossed out and want them to go away!

God designed earthworms as part of His plan for Earth to be a lovely long term home for us humans.
He made them able to digest all sorts of plant material and fresh dead meat – obviously god designed the lower orders with limited longevity unlike we humans who are designed to live forever.
Earthworms only eat living plants if there is no dead plants to eat – so I tell people to leave clippings and fallen laves and flowers around the plants so the worms will come and eat them and recycle the nutrients.

I have lots of earthworms outside even crawling on the walls of my home.Disgusting the walls are covered and if they’re close to the door they end up inside what can I do

I too have worms that come out in full force from the lawn. During the day I can go in my backyard and the top of the grass has worms moving around. It’s disgusting. They crawl off the lawn to my brick patio and crawl all over where my 5 dogs try to eat the crawlers. It’s a nightmare. I never had these worms before but have had them since I had a new backyard put in about 4 years ago. Maybe they used a soil that carries these worms?

I noticed that after I applied Grubex to kill the grubs in my lawn, the earthworms disappeared. Temporarily, I’m going to try spraying some bleach around the garage and driveway per Beverly (04/14/15) or maybe some salt in areas away from vegetation. I was wondering if Ortho Bug b Gone would work?

I applied a generous coating of 12 – 12 – 12 fertilizer to my lawn. The next day it rained and there were no earthworms and no centipedes. Evidently, the critters don’t like fertilizer but my grass sure does!

Today in Jackson Mississippi September 11 2017, I see several dead earthworms outside of sidewalks.
It has not being raining for more than a week.

Yep, pain in the butt! But Early in morning, before it gets really hot, I use a plastic cup to pick up as many as i can see and dump them in the dirt and leaves where my washer drains. Hoping they find a happy home and out of my driveway for the rest of the day!

We had hundreds of dead rain works on the driveway this weekend. No rain for weeks now and no pesticides used. We are near NW Atlanta, Ga., any ideas what would cause a mass die off? Full moon?

I would be so irked if I had to deal with massive amounts of worms. Why do they come out? I would like to know why. I don’t think they are useful to gardens, but my chickens love them. I wish I knew how to gather loads of them. I could save tons on chicken feed!

It is a real shame that nature is such an inconvenience to a lot of you. I would suggest we (two leggers) are more of an inconvenience to nature than the other way around!

SOLUTION: pour a line of salt along your porch & driveway, or use a salt-encrusted Hessian rope that’s been soaked in very strong and briny salt water and lay that along your edges where they mostly can get in. That rope could also be regarded as a nautical theme, if you wanted to see it that way.

Lately, I see earthworms coming in my driveway after heavy rain. is salt be a solution to stop them from crawling in. Thanks

We have hundreds of these creepy crawlies. I never minded them before but now our yard is infested. I believe one of my doxies got a horrible case of roundworms from eating earthworms. If the dirt has been contaminated with roundworms at some point and the earthworms consume it they are now carriers of the parasite. It’s like a vicious circle. They have to go!

Themes in The Road: Where Fiction and Science Meet

We read novels to escape. To relax. To learn. To travel to the places we'd never otherwise see. To be inspired by heroines and heroes. To be challenged to appreciate our lives and the lives of others in new ways. Fiction&mdashlike science&mdashgives us a deeper understanding of ourselves and the world around us.

You know that Cormac McCarthy won the Pulitzer Prize for literature, but you may not know that he also has an interest in mathematics and science, which he engages as a research fellow at the Santa Fe Institute. Now you can join McCarthy's colleagues from SFI as they explore themes and issues raised in The Road.

By Doug Erwin, senior scientist and curator of paleobiology at the National Museum of Natural History of the Smithsonian Institution in Washington, D.C., and part-time resident faculty member of SFI

If Cormac McCarthy knows what caused the cataclysm in The Road, he's not telling, and we're all left to speculate. Was it a nuclear exchange? A massive volcanic eruption? The impact of an extraterrestrial object? We don't know, and in some sense, it does not really matter. But we do know a good deal about what happens after such events. Geologists and paleontologists (who study fossils) have studied how plants and animals responded to the six great mass extinctions of the past 600 million years, as well as smaller events such as massive volcanic eruptions. The first organisms to reappear are often ferns and weedy flowering plants that reproduce and spread rapidly. In the sea, many microbes and some algae spread rapidly.

The deforestation described in The Road would release nutrients from the land into rivers, lakes and the ocean, encouraging further growth. Eventually, slower-growing species would begin to reemerge. Understanding these events is a great scientific challenge, because new ecological communities would most likely operate with different rules than communities that exist before such catastrophes. Why this should happen is not clear, but it emphasizes that the aftermath of such catastrophes may not be a rebuilding of previous relationships but the construction of an entirely new world.

About the Author
Doug Erwin is the author or editor of six books, including Extinction: How Life Nearly Died 250 Million Years Ago, published in December 2005 by Princeton University Press. His latest project is a book on evolutionary innovation through the history of life, which will also explore the similarities and differences between economic and biological innovation. Various field projects have taken Doug repeatedly to China, South Africa and Namibia, and he has done geological field work in various other regions as well. His tombstone will probably read, unfortunately, "He ran a good meeting."

By Jessica Flack, research fellow at the Santa Fe Institute

Conflict is a prominent theme in The Road. It is evident in the ashen landscape, in the bands of marauding men, in the disagreement between father and son about whether to help fellow survivors. Whether conflict&mdashin human societies or in other types of biological systems&mdashis a wholly destructive force or plays an important role in driving the evolution of social and biological complexity is a much-discussed topic of conversation among Cormac McCarthy and his colleagues at the Santa Fe Institute.

The Road provides a lens through which we can examine what the world might be like if conflict were allowed to escalate unchecked or if our attempts to control it failed. The potential for destruction on the scale described in The Road often results from what in evolutionary biology is called (borrowing from Lewis Carroll's Through the Looking Glass) the Red Queen effect&mdashessentially an "arms race" between competing organisms, in which each competitor builds up a comparable arsenal (think of horns, stings and teeth) such that neither one gets the upper hand. If the cataclysm described in The Road was caused by human conflict (the possibility that it resulted from nuclear war immediately comes to mind), it is likely that the severity of the conflict was a product of a Red Queen process.

The conflict and the ensuing arms race should not be seen as solely destructive conditions&mdashthey are also sources of creativity and invention in the sense that the organisms are required to constantly evolve new strategies to keep themselves in the game. What this suggests is that conflict can be both destructive and constructive.

If conflict can have constructive consequences, then wholesale suppression of it might not be the best idea. The potential costs, however, make it critical to get the balance right. A fitting example of the dual costs and benefits of conflict and the ethical complexity it gives rise to can be seen in the history of the Manhattan Project in Los Alamos. Spearheaded by the United States during World War II, the Manhattan Project assembled a team of scientists to develop a nuclear weapon in advance of similar objectives being pursued by the Axis powers. Although the development and use of nuclear weapons resulted in an accelerated end to World War II, it did so at great cost to humanity and irreversibly changed the nature and scope of war. However, the science and scientists driving the Manhattan Project made many important discoveries, including the development of the Monte Carlo algorithm for simulating chain reactions and vastly improving our understanding of computation. Both of these tools are of fundamental importance in the new sciences of complexity pursued by the Santa Fe Institute in peaceful applications, an institute that grew from the ashes of what we might think of as destructive creativity.

About the Author
Jessica Flack is broadly interested in whether there are architectural principles governing the evolution of structure in biological and social systems. Jessica is pursuing the possibility that, if such principles exist, they will be found by comparing construction processes&mdashthe processes by which ordered states arise and persist&mdashin a diverse set of systems that includes single-celled organisms, multicellular organisms, and complex, coordinated aggregates like animal societies. Single-celled and multicellular organisms are relatively well studied from this perspective compared to coordinated aggregates. In recognition of this deficit, Jessica's research is devoted to the study of construction processes at the social level, largely using as model systems animal societies characterized by triadic and higher-order interactions.

By John H. Miller, research professor, SFI, and professor of economics and social science and head, department of social and decision sciences, Carnegie Mellon University

The starkness of the human interactions described in Cormac McCarthy's The Road illuminates one of the most fundamental questions that arises about human nature: Are we fundamentally selfish or altruistic? The answer to this question has perplexed scientists for centuries, including Cormac and his scientific colleagues at the Santa Fe Institute.

True altruism requires not only that we are nice to one another, but that we also do so at a real cost to ourselves without any expectation of any possible gain. Consider that while a honey bee may sacrifice itself by stinging an attacker to save the hive, its hivemates are so closely related genetically that the act provides some benefit to the sacrificial bee (or, at least to its genetic material). The biologist J.B.S. Haldane nicely summarized such a situation when he was asked whether he would give his life to save his brother and answered, "No, but I would to save two brothers or eight cousins." Being nice to someone with an expectation that they will be nice back to you in return also doesn't qualify as true altruism. Leaving a large tip at a restaurant you frequent is a far different act than doing so at a roadside diner that you will never return to again.

In recent years, social scientists have begun to do experiments designed to highlight human altruism. For example, suppose that you are given a pile of 20 one-dollar bills, and in private you are allowed to pocket whatever portion of the pile you would like and place the remaining money (if any) into an envelope that will be given anonymously to someone else. How much money would you give away? Would your choice change if, say, for every dollar you gave away the other person received twice (or half) that amount?

It turns out that the vast majority of the subjects participating in such experiments behave in a manner that reflects very thoughtful decision-making behavior. Moreover, while about half the subjects do tend to be fairly selfish, the remaining subjects often pass substantial amounts of money to others. We are just beginning to understand the limits of such behavior. For example, if you give subjects a bit of "moral wiggle room'' (by perhaps letting an initial coin flip&mdashthat can be easily overturned&mdashdetermine their choice) or reframe the problem as taking money away versus giving money, very different patterns of giving behavior emerge.

About the Author
John H. Miller splits his time between the Santa Fe Institute and the department of social and decision sciences at Carnegie Mellon University. He recently co-authored a book, Complex Adaptive Social Systems: An Introduction to Computational Models of Social Life (Princeton University Press, 2007), that explores how ideas from economics, political science, biology, physics and computer science can be combined to illuminate topics in organization, adaptation, decentralization and robustness. His research ranges from understanding the behavior of critical economic and political systems to the fundamentals of human cooperation and altruism. He was born and raised in Colorado&mdashthe fourth generation of a family of ranchers.

By Chris Wood, vice president, Santa Fe Institute

Can we justify being less than fully truthful to a spouse, child or aging parent to avoid causing them pain? Even this seemingly simple question demonstrates that intentions and motives add immense complexity and depth to the roles honesty and deception play in human interactions. Attempting to understand phenomena such as honesty and deception in their broadest social, biological and physical science contexts is a central research strategy of Cormac McCarthy and his colleagues at the Santa Fe Institute.

"You dont believe me.
I believe you.
I always believe you.
I dont think so.
Yes I do. I have to
" (p. 156).

That interchange between father and son in The Road exemplifies the patchwork of truths, part-truths,"white lies" and deliberate deception that permeates our interactions with each other. The moral and ethical values many societies place on telling the truth may compete with other important motives. Differences among cultures in those roles complicate the picture even further. The oath our judicial system requires of witnesses&mdash"to tell the truth, the whole truth, and nothing but the truth"&mdashacknowledges that truth and falsehood are not a simple binary distinction and emphasizes there are numerous ways, in addition to outright lies, we can cheat the truth.

While we usually think of honesty and deception in the context of human communication, it has long been known that animals use elaborate means of deception. Some nonpoisonous butterflies, for example, have evolved wing patterns similar to those of poisonous species as a means of deceiving and avoiding predators. Animal communication was initially thought to have evolved as a means of facilitating social interactions by the interchange of reliable information. In the competitive world of natural selection, however, deceptive communication becomes as important as reliable communication in achieving competitive advantage. If senders could benefit by deceiving receivers, then the frequency of deception would increase. Receivers would, in turn, evolve means of disregarding deceptive signals, creating what John Maynard Smith has called an "arms race" in which honest and deceptive strategies are "at war" to enable greater fitness. A branch of mathematics known as game theory, originally developed in economics, has become widely used in evolutionary biology for understanding interactions among such competing strategies.

The complex interplay of honesty and deception in the evolutionary context becomes dramatically richer and more nuanced when we consider the intentions of human senders and receivers. (The nature and extent of intentions and other mental states in nonhumans is an important focus of current philosophical and scientific inquiry.) Scientists and philosophers have suggested that the selective advantage of the ability to evaluate the mental states and intentions of others may be one of the important forces driving brain evolution in higher primates and humans. The concept "theory of mind" is now widely used to refer to this ability to attribute mental states (such as beliefs, desires and intentions) to others. Perhaps it should come as no surprise that the size of our neocortex (the region of the brain that has enlarged most extensively in humans compared to other primates) has been reported to correlate with the rate of deception in primate species.

About the Author
Chris Wood became vice president of the Santa Fe Institute in 2005, following faculty positions at Yale University (1976&ndash1989) and as group leader of the Biophysics Group at Los Alamos National Laboratory (1989&ndash2005). From 2000 to 2001, he was interim director of the National Foundation for Functional Brain Imaging, a collaboration involving Harvard Medical School/Massachusetts General Hospital, University of Minnesota and the Minneapolis VA Medical Center, and a number of academic, private and government research institutions in New Mexico. The mission of the foundation was the development and application of advanced brain imaging techniques to mental disorders. Chris is a neuroscientist, whose research interests include imaging and modeling the brain, computational neuroscience and neural computation.

By Jon Wilkins, professor, Santa Fe Institute

Cormac McCarthy and his colleagues at the Santa Fe Institute often use metaphors to explain complex scientific phenomena because researchers from different disciplines may lack a common vocabulary. Genetic imprinting is a phenomenon that is not easy to grasp but can be explained using examples from our experiences or stories. The vivid experiences of the father and son in The Road can help us explain this science.

In The Road, the father and son must negotiate many decisions. When will they stop for the night? Should they open that door? Eat something questionable? Offer help to another traveler? They are two individuals with separate wills, but their paths and their fates are inseparable. In this wasteland, father and son going their separate ways&mdasheach trusting his own judgment&mdashis simply not an option. Every conflict must be resolved into a joint action, one way or another.

Geneticists have discovered that the genes in our bodies are in a similar situation. Of course, the individual organism is the one who takes this or that action, survives or does not, reproduces or does not. Like the father and son, the fates of the genes in each individual are inextricably linked. However, natural selection can favor genes that take on different strategies depending on where the gene came from. These strategies can come into conflict with each other, even for sets of genes that are present within the same individual.

For about 1 percent of our genes, the gene copy that we inherit from our mothers behaves differently from the copy we inherit from our fathers. These genes, known as imprinted genes, have evolved in cases where a gene's optimal behavior differs depending on its parent of origin. Many of these imprinted genes influence our early growth and development, when a paternally derived gene favors more aggressive growth (resulting in a greater drain on maternal resources) than does a maternally derived gene. Because we have one maternally derived and one paternally derived copy of each gene, this leads to an evolutionary conflict between the genes within our own bodies.

In addition to early growth effects, many imprinted genes are expressed in the brain and influence certain aspects of cognition and behavior. We have all felt conflicted over tough decisions. Sometimes we feel as if we were literally of two minds. And of course, we are all familiar with the convention of the little angel and the little devil sitting on our shoulders, whispering in our ears, urging us to do different things. The discovery of these imprinted genes suggests that this feeling may, in fact, have a basis in the genetic conflicts being played out in our brains.

When our genes disagree, it is difficult to predict how the conflict will be resolved. The genes may effectively reach some compromise, or one set of genes may prevail over the other. In some cases, the dynamics of the conflict produce dramatic changes, where each set of genes is worse off than they would have been if they had simply abandoned the conflict sometimes, the compromise solution is worse than losing the conflict outright.

About the Author
Jon Wilkins is an evolutionary biologist working on genetic imprinting, or understanding how genetic traits evolve or die across and within generations. Jon grew up in Los Alamos, New Mexico, and received his PhD from Harvard University. Before joining the Santa Fe Institute in 2004, Jon started his academic career at Harvard as one of only a handful of members of the Harvard Society of Fellows.

By Stephen Lansing, professor of anthropology at the University of Arizona and the Santa Fe Institute

Since the Industrial Revolution, we've come to think of nature as the stage on which the human drama unfolds, separate from humanity. Cormac McCarthy's book brings us back to reality and opens the conversation at the Santa Fe Institute about the impact of humans on the environment.

As early as 1820, one observer wrote that truly "external" nature&mdashnature apart from humanity&mdash"exists nowhere except perhaps on a few isolated Australian coral atolls." Not only do humans directly alter many ecosystems through development and agriculture, we impact apparently untouched habitats in remote regions of the earth through pollution and climate change. Yet we depend on nature for "ecosystem services" such as water purification, pollination, fisheries and climate regulation. For better and for worse, humans are constantly coevolving with species and the environment. Many traditional societies have found creative ways to remind themselves of the critical interdependence of the human and natural worlds&mdashconsider the water temples of Bali, for example. Claude Lévi-Strauss, perhaps the greatest anthropologist of our time, believed that this interdependence is fundamental to human thought.

According to Lévi-Strauss, when we think about nature we are always already thinking about ourselves.

In the past decade, scientific journals and the media have been filling up with reports of our changing relationship to nature. The most prominent example is climate change, but there are many others: the destruction of the world's tropical forests and reefs, the eutrophication of lakes and coastal zones, the beginning of a new age of mass extinction. In The Road, Cormac does not dwell on the scientific details of these catastrophes. Instead, he imagines a world that represents their logical outcome and asks us to imagine what that might feel like. What if there was a near-complete breakdown of the complex networks joining humans with one another and with other species? It's a question that stirs and troubles our sense of who we are.

"There was yet a lingering odor of cows in the barn and he stood there thinking about cows and he realized they were extinct. Was that true? There could be a cow somewhere being fed and cared for. Could there? Fed what? Saved for what? Beyond the open door the dead grass rasped dryly in the wind" (p. 120).

About the Author
J. Stephen Lansing is a professor of anthropology at the University of Arizona, with a joint appointment in ecology and evolutionary biology. He is also a professor at the Santa Fe Institute and director of Yayasan Somia Pretiwi, an Indonesian foundation promoting collaborative research on environmental problems in the tropics. Stephen chaired the anthropology department at the University of Southern California for five years and later became a professor in the School of Natural Resources & Environment and the department of anthropology at the University of Michigan. He has been a Fulbright fellow, a fellow at the Center for Advanced Study in the Behavioral Sciences at Stanford, a lecturer at Udayana University and a researcher at the Institute for Advanced Study in Princeton.

A premier research hub, SFI attracts top thinkers tackling some of the most difficult problems facing society today. On any given day, it is possible to find an ecologist, a chemist and an economist studying climate change, and in the next room, discover a theoretical physicist collaborating with biologists to understand why we age. It is a truly exciting, eclectic organization, and now you can gain additional insight into The Road through their eyes.

More of a think tank than an "ivory tower," SFI is committed to improving science literacy and educating the next generation of scientists so they are comfortable thinking across different disciplines and conceptualizing the world around them in new ways. One of SFI's founders and distinguished scientist, George Cowan, describes scientific inquiry as simply "perpetual curiosity." It is this curiosity that bonds researchers at SFI, regardless of background or profession.

The collection of minds that comprises SFI's distributed network is diverse and the problem-solving techniques multifaceted. The founding institution of what is now known as "Complexity Science," SFI has become a world leader in multidisciplinary research, whose impact on the physical, biological and social sciences is profound and transformative.

There is the treatyse of fysshynge wyth an Angle (or Treatise of Fishing with an Angle) by Dame Juliana Berners, published in 1496 as part of the Book of St Albans.

It seems clear that angle means hook. Just be grateful that you don't teach hooking.

"Angling" is another term for fishing, and it goes back a long way. At least to Izaak Walton (9 August 1593 – 15 December 1683) and his famous guide.

Etymology Online states that the word "angle" in Old English meant hook. Thus an angler uses an angle.

I'll dive in and take the bait! I think we often use the word “angler” to "gender neutralize” the word “fisherman”. I, too, have wondered where the word “angler” comes from… and first thought maybe it was taken from “angle worm”… It turns out it's the other way around. “Angle worm” is an Americanism from 1825-35 – used chiefly in the northern, north midland and western U.S. that describes worms such as earthworms that are used as bait "by anglers". An angle worm is not a particular species of worm. Aporrectodea caliginosa is very common species of earthworm (a large, unpigmented species) found in gardens and agricultural fields and is sometimes referred to as “angle worms”. The moderately sized species, Lumbricus rubellus, is commonly sold as fishing bait and is often called “leaf worms” or “beaver tails” or “angle worms”. There are over 2,500 species of earthworms!

I've heard others say the word “angler” comes from the “angle” between the rod and line of a fishing rod… and I looked it up to try to confirm whether that was the case…

As defined by Random House Webster's College Dictionary:

  1. a person who fishes with a hook and line.
  2. a person who tries to get something through scheming.
  3. any of various large-mouthed marine fishes of the family Lophiidae, having a wormlike lure dangling from the head for attracting prey.

…and Webster’s dates the origin of the word “angler” at 1545–55 A.D.

From the Online Etymology Dictionary:

angle (v.1) - "to fish with a hook," mid-15c., from Old English angel (n.) "angle, hook, fishhook," related to anga "hook," from PIE *ang-/*ank- "to bend" (see angle (n.)). Cf. Old English angul, Old Norse öngull, Old High German angul, German Angel "fishhook." Figurative sense is recorded from 1580s.

"It is but a sory lyfe and an yuell to stand anglynge all day to catche a fewe fisshes." - [John Palsgrave, 1530]

The noun “angle” was derived from an Indo-European root “ank” meaning “to bend”. The word “angle” entered the language in the Old English period as “angel”, and was based on Germanic *angg- (source also of German angel ‘fishing tackle’) and was used to mean “hook for fishing”. It was spelled “angel” in Old English, but it is unrelated to the Biblical sort of “angel” (which is based on a Greek word for “messenger”). “Angle” was also was often used to refer to the rod and line as well as the hook and was in use as such until the 19th century.

The verb "angle" has been used to mean "to fish" since the late 15th century, and "angler" as meaning "one who fishes with a hook and line" has been in use since the mid-16th century.

“Ank” also is the base of the Greek "ankos" (a bend) and the English words “ankle” and "anchor."

An earlier form of the word appears to have been applied to a fishhook-shaped penninsula area of Schleswig within in the larger Jutland peninsula by its former inhabitants. Calling their homeland Angul, they came to be referred to as Angles. After the fall of the Roman Empire, the Angles (Germanic peoples also referred to as the Anglo-Saxons) emigrated westward to a new island land. Both the island “country’s name, England, and the language, English, now enshrine a reminiscence of the Angles fishhooks. The ancient homeland area of the Angles encompasses the present-day Angeln (sometimes called Anglia) in the northern Schleswig-Holstein, Germany.

The “Treatyse of Fysshynge with an Angle” (or - Treatise of Fishing with a Hook/Hook and Line) was published as part of the second edition of “The Boke of St. Albans” in 1496. The "Treatyse" is the most complete early reference work on fly fishing… and it’s thought to have been written by Dame Juliana Berners - a nun and noblewoman. Various accounts in literature describe her as a woman of keen intellect and an accomplished practitioner and avid devotee of outdoor sports, including angling and hunting. The text includes instructions on how to make a rod, line, hooks, instructions for twelve fly patterns and the season of their optimum utility, and hints about how to catch the common varieties of British fish, and includes substantial information on fishing destinations and bait selection. Perhaps most remarkable are the essays on the virtues of conservation, respecting the rights of streamside landowners, and angler’s etiquette. These concepts would not come to be commonly accepted and advocated in the angling world until 400 years after the publication of the "Treatyse", yet today they embody the ethical bedrock of sport fishing. The "Treatyse" predates Izaak Walton’s “The Compleat Angler” (1653) by about 150 years. “The Compleat Angler” is arguably rated as the third most published book written in English, with Shakespeare’s works and the Bible being the other two.

The following is adapted from an entry on "The Word Detective" website:

So, it seems, the word “angler” has nothing to do with the “angle” between one’s line and rod. That’s an entirely different kind of “angle.” Unlike the archaic word “angle” meaning fish hook - this second word “angle” is still in common use today - and it means: “the relation of one line to another at their intersection”, usually measured in degrees. This noun - “angle” - in the sense of a ‘figure formed by two intersecting lines’ or a ‘projecting corner’ - as in ‘the angles of a building’ - entered the language in the 14th century (Chaucer is its first recorded user). This “angle” is derived from the Latin “angulum,” meaning “corner” or “to slant” or “bend” (“The road angles to the right.”, “The trout angled downstream.”) But - if you go back far enough in this second word’s history, you run into the same Indo-European root “ank” again! So the two “angle” nouns are related. They are still considered separate words, though, because they followed different paths into English.

I think it is of note, however, and very interesting, that some figurative uses of the word “angle” illustrate how connected these two words are in their practical use today:

The verb “to angle,” in an extension of its meaning “to fish,” has long been used to mean “to use subtle or devious means to obtain something,” (“Bob is angling for a promotion” or “I think Tim was angling for a compliment on his cooking.”)

Similarly, we use the noun “angle” as slang in hinting at something “crooked”– a “scheme” or “devious plan” (“I wonder what his angle is?) which is unlike (“I know when he’s being straight with me.”)

and, more innocently, as in taking one “side” or “slant” or particular “perspective” or “approach” or “aspect” or “viewpoint” - of an event, problem or subject (“I didn’t agree with the angle the reporter took with her story.” or “The accountant emphasized the tax angle of the leasing arrangement.”)

And we use the word to invoke the sense of an angle of attack – of “angling for an angle”, so to speak…(“Lefty’s always looking for an angle to fleece the tourists.”) Lefty's an altogether different kind of angler. ! 

Watch the video: Δημιουργία Κομποστοποιητή - Οι κηπουροί του mega (June 2022).