Chapter 9: Evolution and Behavior Flashcards
What is polygamy?
mating system in which some individuals attract multiple mates, while others attract none
What is monogamy?
mating system in which most individuals mate and remain with one other individual
This type of polygamy occurs when individual males mate with multiple females:
polygyny
This type of polygamy occurs when individual females mate with multiple males:
polyandry
In reciprocal altruism, individuals generally give up something of _____________________ in exchange for something of _____________________.
relatively low value ; great value at a later time
A population’s environment sometimes changes too quickly for natural selection to adapt the individuals in the population to the environment. In these situations:
the individuals’ instincts can no longer be trusted to elicit behavior that maximizes reproductive success
Babies in the U.S. quickly and easily develop a fear of snakes. Yet they don’t easily develop a fear of guns. Why?
Evolution can be slow in producing populations that are adapted to their environments
What are the modes of communication that are seen among animals?
chemical, visual, acoustical
Acoustical communication among animals:
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.
Visual communication among animals:
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.
Chemical communication among animals:
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)
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:
sexual selection
In Belding’s ground squirrels, why are females much more likely than males to engage in altruistic behavior by sounding alarm calls?
Females tend to remain in the area in which they were born, so the females that call are warning their own kin.
Why is this goose rolling a beer can back to her nest?
She’s exhibiting a fixed action pattern that directs her to retrieve any item that even vaguely resembles an egg.
______________________ is an action or signal on the part of one organism that alters the behavior of another organism.
Communication
Members of the sex with less energetic investment in reproduction:
will compete among themselves for access to the higher-investing sex.
In black widow spider mating, the male ___________________________ and the female ___________________________.
breaks off his sexual organ inside the female ; kills and eats the male
What conditions are conducive to reciprocal altruism?
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
How do you enhance cooperation with reciprocal altruism?
1) tinker with the perceived costs and benefits
2) distinguish cheaters and kind people
3) reduce the perceived vulnerability of partners
what does it mean to “tinker with the perceived costs and benefits”?
reduce the perceived cost to the other person + accentuate the benefit that you’ll receive from their cooperation
what does it mean to “distinguish cheaters and kind people”?
build reputations + use “honest signals” that can’t be faked + keep track of/punish cheaters
what does it mean to “reduce the perceived vulnerability of partners”?
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
why are people nice to each other?
1) shared genes (kin selection)
2) reciprocal altruism
what are two ways for a gene to increase its market share?
1) direct fitness
2) indirect fitness
