Question 1

The earliest nervous system fossils are from a little over half a billion years ago, yet the earliest fossilized life is known from 3.5 billion years ago. Do you think behavior could have emerged before the origin of a nervous system? Give examples to support your answer.

Accepted Answer

The answer of The earliest nervous system fossils are from...

Question 2

How does Dictyostelium discoides, a cellular slime mold, demonstrate behavior?

Accepted Answer

When resources are limited, Dictyostelium discoides cells aggregate to form a multicellular structure known as a slug, which can then migrate to a new location to find better conditions.

Question 3

Which of the following is not a behavior that likely evolved because it has a positive effect on the indirect component of inclusive fitness?

Accepted Answer

The behavior described in A does not affect the indirect component of inclusive fitness because the female wasp is helping an unrelated individual, which does not contribute to the propagation of her own genes through relatives.

Question 4

How are memories created in the sea slug Aplysia?

Accepted Answer

Memories in the sea slug Aplysia are created through changes in the synapses, the points of communication between neurons. This process involves alterations in synaptic strength, rather than changes in axon length or myelin sheath thickness.

Question 5

Explain how the vertebrate brain can reflect the evolutionary history and ecological specialization of a species.

Accepted Answer

The answer of Explain how the vertebrate brain can reflect...

Question 6

Based on Kawecki's experiments on learning in fruit flies, would you expect fast learning to more readily evolve in populations characterized by high or low extrinsic mortality (assuming that it does provide an advantage)? Explain your reasoning.

Accepted Answer

The answer of Based on Kawecki's experiments on learning in...

Question 7

The mouthless jellyfish, Mastigias paupua, has a symbiotic relationship with the photosynthetic organisms that live inside its tissues and can absorb nutrients from the soil at the bottom of a body of water. The jellyfish migrates upward in the water column toward the surface during the day and descends at night. Provide one proximate and one ultimate explanation for this behavior.

Accepted Answer

The answer of The mouthless jellyfish, Mastigias paupua, has a...

Question 8

Mexican colonial web-building spiders nest in colonies that range in size from ten to thousands of individuals, with each individual occupying their own web within the colony. Colonies are frequently attacked by predatory wasps. Individuals in larger colonies suffer lower predation than those in smaller colonies. The data in the graph below are from a study performed by Uetz et al. (2002), where they measured the distance at which spiders responded to potential predators. Open bars are for spiders on the interior, and colored bars are for spiders on the periphery of the colony. What type of grouping benefit is demonstrated here?

Accepted Answer

The answer of Mexican colonial web-building spiders nest in colonies...

Question 9

What do sensory maps of the somatosensory cortex of burrowing mammals show?

Accepted Answer

The answer of What do sensory maps of the somatosensory...

Question 10

You are studying crickets and notice that some male crickets produce long songs, while others produce shorter songs. Describe one method that would allow you to determine whether these differences have at least a partial genetic basis.

Accepted Answer

The answer of You are studying crickets and notice that...

Question 11

In the paper wasp, although all females in a nest are physiologically capable of reproducing, a single female monopolizes almost all reproduction, while other females help rear her offspring. In some nests, female helpers are unrelated to the reproducing female. The most likely explanation for this is that these helpers gain ________ benefits, such as ________.

Accepted Answer

Helpers gain direct benefits by potentially taking over the reproductive role if the current reproducing female dies, offering them a chance to reproduce themselves.

Question 12

Describe the two hypotheses related to the evolution of nervous systems in animals. Be sure to include discussion of the sister groups of animals and mention specifically how sponges and ctenophores play a role in each hypothesis. Feel free to sketch a phylogeny for either or both hypotheses if it helps.

Accepted Answer

The answer of Describe the two hypotheses related to the...

Question 13

Dictyostelium discoides, also known as cellular slime mold, is a

Accepted Answer

Dictyostelium discoides is a single-celled eukaryote that lives in the soil, where it feeds on bacteria. It is known for its unique life cycle, which includes a phase where individual cells aggregate to form a multicellular structure, but it remains a eukaryotic organism at the cellular level.

Question 14

Critique the following statement: Some individuals in nearly all species do not breed. A reasonable explanation for this is that species maintain non-breeding individuals as insurance. Non-breeding individuals are hardier and exist to replenish the population after a period of harsh conditions.

Accepted Answer

The answer of Critique the following statement: Some individuals in...

Question 15

Which of the following is true regarding the evolution of neurons?

Accepted Answer

Some proteins involved in the formation of neurons, such as those related to signaling pathways, are indeed found in plants. These proteins are part of ancient biochemical pathways that predate the evolution of neurons and are involved in various cellular processes across different life forms, including plants.

Question 16

The figure below shows the number of predatory attacks per individual in water skater groups of different sizes. The information in the graph demonstrates which benefit of grouping?

Accepted Answer

The answer of The figure below shows the number of...

Question 17

A new altruistic allele arises in a population such that individuals with the allele give up some personal reproduction in order to help their parents raise offspring. Instead of producing six offspring of their own, individuals with the allele produce only three offspring. The parents would also normally produce six offspring, but are able to produce 12 with the help of the altruistic individual. Using Hamilton's rule, determine whether this altruistic allele is likely to increase in frequency in the population. Show your work.

Accepted Answer

The answer of A new altruistic allele arises in a...

Question 18

When population density is high and food availability is low, stress steroids are elevated in snowshoe hares, preventing females from reproducing. A biologist argues that this mechanism has evolved because it keeps the population from overexploiting its food resources and driving itself to eventual extinction. Do you agree with this argument? Why or why not?

Accepted Answer

The answer of When population density is high and food...

Question 19

Is it theoretically possible for altruistic behavior to evolve if relatedness is very low (for example, r = 0.05)? Why or why not?

Accepted Answer

The answer of Is it theoretically possible for altruistic behavior...

Question 20

In what way(s) do(es) Aplysia flexibly respond to stimuli?

Accepted Answer

The answer of In what way(s) do(es) Aplysia flexibly respond...

Quiz 16: Brains and Behavior