Chapter 4: Behavioral Ecology

Question 1

Behavior? Behavioral ecology?

Answer 1

Behavior: is the observable response of organisms to external or internal stimuli. The sub-field emphasizes evolutionary explanations: an animal showing optimal behavior maximizes its fitness.
Behavioral ecology: the study of how behavior contributes to the differential survival and reproduction of organisms

Question 2

Altruism? What attempted to explain the existence of altruism (advantages?)

Answer 2

Altruism: behavior that benefits others at personal cost

Attempted: group selection: the premise that natural selection produces outcomes beneficial for the whole group or species; in a group of altruists, each is willing to subordinate its interests for the good of the group (best for overall survival)
In other words, they would enhance the survival of the group, they would not overexploit its resources and die out (this would kill off the group)

Question 3

What attacked the idea of altruism?

Answer 3

the individual selection did; it proposed that particular traits generally are selected because they benefit the survival and reproduction of the individual rather than the group (brought to attention by George C. Williams)

Question 4

What was the three traits that William stated would be a good argument against group selection?

Answer 4

1) mutation: in a population where individuals have limited resources, mutant individuals that readily use resources for themselves or their offspring will have an advantage
ex: produce two eggs, but if one day three eggs are produced and they live, then the population/bird/etc,, will mutate and now produce three eggs

2) immigration: selfish individuals that lay more eggs could immigrate from other areas. Populations are rarely sufficient isolated to prevent the immigration of selfish individuals from other populations

3) lack of an ability to predict future resource availability: group selection claims that individuals can assess and predict future food availability and population density within their own habitat, but they can not so what now

Question 5

coefficient of relatedness? in relation to altruism

Answer 5

Coefficient of relatedness: the probability that any two individuals will share a copy of a particular gene by descent is a quantity, r, called –

the implication of the coefficient of relatedness for the evolution of altruism (William figured this out), meaning an organism not only can pass on its genes through having offspring but can also pass them on through ensuring the survival of siblings, nieces, nephews, and cousins

Question 6

Inclusive fitness? Kin selection?

Answer 6

is used to designate the total number of copies of genes passed on through one’s relative, as well as one’s own reproductive output

Kin selection: selection for behavior that lowers an individual’s own fitness but enhances the reproductive success of a relation- Example: helps explain the altruistic act of alarm calls, the Belding’s ground squirrel sentry emits an alarm call to warn other individuals, who are often close kin, of the presence of a predator. (by doing so the the sentry draws attention away from the others but becomes an easier target itself)

Question 7

Altruism? In insects? Eusociality?

Answer 7

Altruism in social insects arises partly from genetics and partly from lifestyle

Eusociality: organisms with a reproductive division of labor, overlapping generations, cooperative care of young, and ‘caste’ system.

[In ants] extreme form of altruism is the evolution of sterile castes in social insects, in which the vast majority of females, known as workers, rarely reproduce themselves but instead help one reproductive female (the queen) to raise offspring
- males develop from the queen’s unfertilized eggs and are haploid
- each daughter receives an identical set of genes from her father. The other half of a female’s genes come from her diploid mother

COR: (r) of sisters is 0.50 (from father) + 0.25 (from mother) 0.75
meaning females are more related to sisters than their own offspring.. Thus, it is better for the females to stay in the colony and care for other female offsprings of the queen, which are their full sisters. - a system called haplodiploidy

Question 8

Hamilton’s Rule?

Answer 8

he proposed the first quantitative measure for predicting when natural selection would favor altruistic acts among related individuals

Three key variables in an altruistic act:
1) benefit of the recipient (B)
2) cost to the altruist (C)
3) coefficient of relatedness (the fraction of genes that, on average, are shared; r)
natural selection favors altruism when

rB>C

Question 9

Reciprocal altruism? (example)

Answer 9

altruism is known to exist between unrelated individuals
- also known as a phenomenon called “you scratch my back, ill scratch your”

• Reciprocal altruism: the cost to the animal of behaving altruistically is offset by the likelihood of a return benefit (ex: when chimps groom each other to get rid of parasites) (bat: the hungry female will solicit food from another female by approaching and grooming her. The female being groomed then regurgitates part of her blood meal for the other)

Question 10

Game theory? in behavioral ecology? in evolutionary stable strategy (ESS)?

Answer 10

Game theory: branch of mathematics and economics that studies the interaction between agents.

Behavioral ecology: the agents are individuals who choose different strategies in interactions with other individuals so as to maximize their benefits (ex: when the best time to flight or fight)

ESS: is a behavioral strategy, adopted by a population, and cannot be invaded by any other strategy. In other words, if all members of a population adopt the strategy, then no one would get a greater benefit to individuals over the long term.
Ex: two suspects are arrested and decided to be quiet, when the police was counting on them saying something, and now they get a light sentence bc no one said anything, but reality is no one knows how they’ll react and both testifying is best bc they’ll get less years than if one testifies and the other does not, so basically game theory or ESS discourages cooperation between individuals.

Question 11

Group living: advantages or disadvantages?

Answer 11

Advantages: reduce predator success in two ways: through increased vigilance and through protection in numbers
Disadvantage: promote competition for food and increased transmission of parasites and other diseases

Question 12

Vigiliance? Many Eyes hypothesis?

Answer 12

Many Eye hypothesis: “if each pigeon occasionally looks up to scan for a hawk, the bigger the group, the more likely that one bird will spot the hawk early enough for the flock to take flight.
– by living in groups, individuals may decrease the amount of time each spends scanning for predators and increase the time they have to feed (some birds may never look up and be free-riders of this method, but one who always scan will always leave and thus discourages cheating)

Question 13

Vigilance (keeping watch) and group size?

Answer 13

Large animals can take down disproportionately large size that a single predator would be unable to handle. (ex: lions, hyenas, and wolves// there could be the exploitation of discoveries tho, freeriders) HOWEVER, having a large group is not everything. There are times when the group needs to be an exact number (if it increases) the group is no longer beneficial.. aka whale groups 3-5 is good but at 6, it’s better to be alone at that point

Question 14

Selfish herd?

Answer 14

living in groups offers protection from the “selfish herd” , so animals will get in large groups to have a 1 in 100 chance of being selected, than being by themselves and having a 1 on 1 chance of being targets by a predator

Question 15

Foraging behavior? Performed in what terms?

Answer 15

Foraging behavior: The search for Food, performed often in terms of optimality modeling, which predicts that an animal should behave in a way that maximizes the benefits of a behavior minus its costs

In this case, the benefits are the nutritional or caloric value of the food items, and the costs are the energetic or caloric costs of movement.

Question 16

optimizing foraging behavior? In regards to behavior and territory?

Answer 16

when the difference between the energetic benefits of food consumption and the energetic costs of food gathering is maximized, and individual organism is said to be optimizing its foraging behavior
- can be used to examine behavior issues as well: how large territory is needed to defend
a) too small a territory would contain insufficient food
2) too large a territory would be too energetically costly to defend

Question 17

What does optimal foraging maximize and minimize? What are the two thing that affect/influence foraging activity?

Answer 17

Optimal foraging maximizes the benefits and minimizes the costs of food gathering

1) foraging activity is influenced not only by energetic efficiency but also by the threat of natural enemies
2) changing the abiotic environment can have drastic effects on animal behavior and the interaction between predator and prey
– weather/climate change also affect animal behavior and foraging activity (ex: increased snowfall can subject moose to heavier predation by wolves, as both congregate (getting into packed areas) in relatively snow-free areas)

Question 18

Territory

Answer 18

Territory: a fixed area in which an individual or group excludes other members of its
cheetahs: they establish large territories to hunt successfully

Question 19

Game theory establishes what when individuals fight for resources?

Answer 19

The game theory establishes whether individuals fight for resources or flee from opponents

“if larger behave like a hawk; if smaller, behave like a Dove; if equally matched, adopt the Bourgeois strategy”

Age- Young animals may give up sooner in a fight with an older male to avoid the risk of getting injured; but, for an old male, any chance to fight is a time to mate

Question 20

Four dating types of mating system:

Answer 20

Promiscuous: with each female and each male mating with multiple partners within a breeding season
Monogamy: each individual mates exclusively with one partner over at least a single breeding cycle and sometimes for long
Polygamy: system in which either males or females mate with more than one partner in a breeding season
- there are two types:
1) polygamy: a system in which either male or female with more than one partner in a breeding season
—-> a) polygny: one male mates with more than one female, but female mate only with one male
———-> b) polygny: one female mates with several males, but males mate with only one female

Question 21

mate-guarding hypothesis?

Answer 21

It is one of the explanations for the monogamous mating systems: theorizes that a male stays with a female to protect her from being fertilized by other males (advantageous when receptive females are widely scattered and difficult to find)

Question 22

Male assistance hypothesis?

Answer 22

It is one of the explanations for the monogamous mating systems: maintains that males remain with females to help them rear their offspring (prevalent in birds because eggs and chicks take a considerable amount of parental care)

Question 23

female-enforced monogamy hypothesis?

Answer 23

It is one of the explanations for the monogamous mating systems: suggests that females stop their male partners from being polygynous (aka : beetles stopped their male partners from dating)

Question 24

Polygynous mating systems: three possible explanation?

Answer 24

One male mates with more than one female in a single breeding system: These systems mean the men do very little to care.

1) Resource- based polygyny: male believes its advantageous; basically have resources and that why they get females (bad for female bc competition)
2) harem mating structures: they are dominant males and command the mating, every new dominant male does not last long, so when a new one comes, they kill off the existing young so females can reproduce earlier
3) communal courting: flashiest males perform the vast majority of the matings (so if he goofy, they f him, and he just bangs to as many as he want cuz he goofy)

Question 25

Polyandrous mating systems?

Answer 25

• one female mates with many males
  1) Actitis macularia: eggs are unlimited, just got to find men who can incubate the eggs
  2) Kalahari meerkats: women are the top-dog, the dominant one and highest social ranking
  3)

Question 26

Sexual Selection? What two forms can it take? Runaway selection?

Answer 26

Sexual selection: involves mate choice and mate competition- is a selection that promotes traits that will increase an organism’s mating success
1) intersexual selection: members of one sex, usually females, choose mates based on particular attractive characteristics such as color of plumage or sound of courtship song
ex: hangingflies- male will give gift to eat, longer it takes to eat it, the more sperm he can transfer
—-> runaway selection: does not care about what the male has just prefers a male who looks good (peacocks)

2)intrasexual selection: members of one sex, usually males, compete over partners, and the winner performs most of the matings
— if they can fight, they can mate essentially bc strong (fights may break out)

Question 27

Fisher’s principle?

Answer 27

states that a 1:1 sex ratio is an evolutionary stable strategy (ESS)
“We can think of male and female sexes as different strategies in an evolutionary game. As it turns out, a 1:1 sex ratio is often the ESS. If a population contained 20 females for every male, then a parent whose offspring were exclusively males could expect to have 20 times the number of F2 progeny produced by a parent with the same number of female offspring. Under such conditions, natural selection would favor production of males, and males would become prevalent in the population. At such a point, females would be at a premium, and natural selection would favor their production. Such constraints operate on the numbers of both male and female offspring, keeping the sex ratio at about 1:1.” -book