After a leg injury, pain makes a person avoid putting too much weight on the affected leg. Shielding the injury gives it time to heal. An injured insect shows no such shielding response. Some have cited lack of such a response as evidence that insects do not feel pain. But insects do produce substances similar to our natural pain killers. Is the presence of these compounds in insects sufficient evidence to conclude that they feel pain

Describe the location of the nerve cord in arthropods. (Think of the crayfish.)

Dogs have heightened senses and can often hear and smell things that a human cannot. For this reason, dogs are often used to detect particular odors. For example, at airports, dogs are used to sniff for bombs and drugs. The dogs help keep people safe so that nothing harmful gets on a plane. Dogs are also often sent on search parties to find people who are missing. They will smell a shirt that has the scent of a person on it. Then they will search for a similar scent. When they get on the trail of a scent, dogs will follow it with their nose until they find the missing person. Engineers are working to design an artificial, or human-made, nose that can act like a dog's nose. They have analyzed the way a dog detects a scent and have begun to mimic it in their designs. Apply If you had a keen sense of smell like that of a dog, what do you think you would smell that you cannot smell now?

In a controlled experiment , seagull chicks to peck at a red stick over a cardboard model of an adult seagull's beak a. reflexs b. super stimulus c. chainning d. inhibition

which of the following is true of chemical signals? - they can only be perceived by the intended reciever - they require physical contact between a molecule and a receptor adapted to fit that molecule - they are perceptible from longer distances, on average, than mechanical signals such as sound waves - they are used almost exclusively in a mating or courtship context