Chapter 9: Evolution and Behavior

Question 0

What is polygamy?

Answer 0

mating system in which some individuals attract multiple mates, while others attract none

Question 1

What is monogamy?

Answer 1

mating system in which most individuals mate and remain with one other individual

Question 2

This type of polygamy occurs when individual males mate with multiple females:

Answer 2

polygyny

Question 3

This type of polygamy occurs when individual females mate with multiple males:

Answer 3

polyandry

Question 5

In reciprocal altruism, individuals generally give up something of _____________________ in exchange for something of _____________________.

Answer 5

relatively low value ; great value at a later time

Question 6

A population’s environment sometimes changes too quickly for natural selection to adapt the individuals in the population to the environment. In these situations:

Answer 6

the individuals’ instincts can no longer be trusted to elicit behavior that maximizes reproductive success

Question 7

Babies in the U.S. quickly and easily develop a fear of snakes. Yet they don’t easily develop a fear of guns. Why?

Answer 7

Evolution can be slow in producing populations that are adapted to their environments

Question 8

What are the modes of communication that are seen among animals?

Answer 8

chemical, visual, acoustical

Question 9

Acoustical communication among animals:

Answer 9

Sounds that trigger behavioral. These include the alarm calls of Belding’s ground squirrels, the complex songs of birds, whales, frogs, and crickets vying for mates, and the territorial howling of wolves.

Question 10

Visual communication among animals:

Answer 10

Individuals often display visual signals of threat, dominance, or health and vigor. Examples include the male baboon’s baring of his teeth and the vivid tail feathers of the male peacock.

Question 11

Chemical communication among animals:

Answer 11

Possible through PHEREMONES: molecules released by an individual into
the environment that trigger behavioral responses. (ex. the airborne mate attractant of the silkworm moth, territory markers such as dog urine, and trail markers used by ants)

Question 12

Song and bright colors make male birds conspicuous to predators. The large, gaudy tail of the peacock may be a hindrance in activities such as feeding and flight. Yet these features evolved because of:

Answer 12

sexual selection

Question 13

In Belding’s ground squirrels, why are females much more likely than males to engage in altruistic behavior by sounding alarm calls?

Answer 13

Females tend to remain in the area in which they were born, so the females that call are warning their own kin.

Question 14

Why is this goose rolling a beer can back to her nest?

Answer 14

She’s exhibiting a fixed action pattern that directs her to retrieve any item that even vaguely resembles an egg.

Question 15

______________________ is an action or signal on the part of one organism that alters the behavior of another organism.

Answer 15

Communication

Question 16

Members of the sex with less energetic investment in reproduction:

Answer 16

will compete among themselves for access to the higher-investing sex.

Question 17

In black widow spider mating, the male ___________________________ and the female ___________________________.

Answer 17

breaks off his sexual organ inside the female ; kills and eats the male

Question 18

What conditions are conducive to reciprocal altruism?

Answer 18

1) repeated interactions, 2) high benefit to recipient relative to the cost to the actor, and 3) ability to keep tabs on people/punish cheaters

Question 19

How do you enhance cooperation with reciprocal altruism?

Answer 19

1) tinker with the perceived costs and benefits
2) distinguish cheaters and kind people
3) reduce the perceived vulnerability of partners

Question 20

what does it mean to “tinker with the perceived costs and benefits”?

Answer 20

reduce the perceived cost to the other person + accentuate the benefit that you’ll receive from their cooperation

Question 21

what does it mean to “distinguish cheaters and kind people”?

Answer 21

build reputations + use “honest signals” that can’t be faked + keep track of/punish cheaters

Question 22

what does it mean to “reduce the perceived vulnerability of partners”?

Answer 22

make the first step: gifts! (if you start it, more people will be inclined to trust you & not feel vulnerable) + acknowledge debts clearly and concretely

Question 23

why are people nice to each other?

Answer 23

1) shared genes (kin selection)

2) reciprocal altruism

Question 24

what are two ways for a gene to increase its market share?

Answer 24

1) direct fitness

2) indirect fitness

Question 25

direct fitness:

Answer 25

involves the reproductive success of an individual (increase the number of offspring I produce)

Question 26

indirect fitness:

Answer 26

involves some of the genetic material that is shared by an individual and that individual’s relative (increase the number of offspring my kin have - they also carry many of my genes)

Question 27

inclusive fitness:

Answer 27

the sum of an individual’s reproductive success through it’s offspring PLUS its influence on its relatives’ reproductive success, (devalued in proportion to the degree of relatedness to the relatives, and minus the part of the individual’s reproductive output due to the actions of others)

Question 28

What is Hamilton’s rule?

Answer 28

B * r > C
The cost of the act (to you) must be less than the benefit obtained times the coefficient of relatedness. ***species tend to evolve behavior that maximizes inclusive fitness

Question 29

If the cost of the act is GREATER than the benefit obtained times the coefficient of relatedness (B * r < C),

Answer 29

this behavior will NOT maximize inclusive fitness; Hamilton’s theory predicts this behavior CAN NOT evolve by natural selection