Chapter 8: Behavioral Ecology

Question 1

 Ethology: the basic study of _____ _____

Answer 1

animal behavior

Question 2

 By focusing on events that take place during an animal’s lifetime, this approach (a “_____ ” question about behavior) seeks to explain behaviors in terms of their _____ or _____ causes.

Answer 2

how
immediate
proximate

Question 3

 By addressing previous events that influenced the features of an animal as we know it today, this approach (a “_____ ” question about behavior) seeks to explain behaviors in terms of their _____ or _____ causes.

Answer 3

why
evolutionary
ultimate

Question 4

 It is usually a _____ to assume that _____ are under the control of one or few _____ . It also _____ to assume that an individual that has an _____ associated with a certain behavior will always perform that behavior.

Answer 4

mistake 
behaviors 
genes
wrong
 allele

Question 5

 Instead 2 individuals with _____ alleles may behave _____ . Individuals often _____ their behavior when in different environments. Genes affect behaviors and natural selection molds behaviors over time.

Answer 5

identical
differently
change

Question 6

 Optimal foraging theory best describes the foraging behavior of animals that feed on _____ prey and applies less well to animals feeding on _____ prey

Answer 6

immobile

mobile

Question 7

 P=E/t
 Items with high _____ (P) are generally preferred
 E = _____ _____ _____ , i.e., energy gained minus energy invested in obtaining & processing the food
 t = _____ _____ & _____ _____ invested in obtaining & processing the food

Answer 7

profitability
net energy value
encounter time & handling time

Question 8

 Optimal foraging proposes that animals will maximize the amount of energy required per unit of feeding time. Optimal foraging relies on the assumption that _____ _____ acts on the _____ _____ of animals to maximize their rate of energy gain.

Answer 8

natural selection

foraging behavior

Question 9

 If an animal if foraging optimally and has a choice between two equally abundant food items, it will select the food with the _____ _____.

Answer 9

higher P.

Question 10

 Net energy gained = (Total energy obtained) – (Cumulative energy investment) Drops off as animal cannot carry nor ingest more
 At first, the total amount of energy that an animal obtains from its food _____ _____ with the effort it invests – that is, with the time and energy it spends searching for, capturing, subduing, and consuming food.
 At some point, however, a further increase in foraging effort provides relatively little additional energy, and the net energy gain begins to decrease. Several factors may cause this _____ , including a limitation on how much food the animal can carry or ingest.

Answer 10

increases rapidly

decrease

Question 11

 Marginal Value Theorem as applied to _____ of _____ _____ :
 Within a patch, the marginal value for longer time has _____ returns
 Slopes of straight, solid lines = Energy gained / time
 Tangent maximizes profitability (slope) & determines _____ giving up _____

Answer 11

profitability of foraging patches
diminishing
optimal
time

Question 12

 Marginal Value Theorem can be used to evaluate the influences of distances between _____ , the quality of the _____ in a patch, and the animal’s energy _____ _____ on the giving up time.

Answer 12

patches
food
extraction efficiency

Question 13

 Marginal Value Theorem has also been extended to other “giving up” problems in behavioral ecology, including how long to _____ and when to _____ guarding a nest and seek other mates.

Answer 13

copulate

cease

Question 14

 Marginal Value Theorem assumes that a foraging animal will _____ patches containing varying amounts of food. The animal’s rate of energy gain in a patch is initially _____ but _____ as the animal _____ the food supply in the patch. The time the animal spends in a patch should optimize its rate of energy gain.

Answer 14

encounter
high
decreases
depletes

Question 15

 Foraging (and other) decisions can be modified by _____

 Prey sometimes _____ their _____ of predators to those predators. E.g., stotting / pronking

Answer 15

predators
communicates
awareness

Question 16

 There is a wide variety of ways that prey seek to prevent attack once they are seen.
 When threatened some prey make sudden movements or place their body in positions that startle a predator. Some prey send predators a signal, in effect conveying, “____ ____ ___, I’m faster than you, ____ ____ ___ ____ ____.”

Answer 16

“I see you,

so don’t bother to attack me.”

Question 17

 Members of a ____ can enjoy higher reproductive success than ____ ____
 As the number of individuals in a group increases, the chance of being the one attacked decreases.

Answer 17

group

solitary individuals

Question 18

 Main Advantages of living in a group: access to ____ , protection from ____ , and improved ____ success.
 Other benefits include gain access to good breeding sites or abundant supplies of food, and shared responsibilities if feeding and protecting the young.

Answer 18

mates
predators,
foraging

Question 19

 Main Disadvantages of living in a group: greater ____ ____ , more ____ for food, and higher risk of ____ .

Answer 19

energy expenditures
competition
disease.

Question 20

 Groups should be a size at which the benefits of belonging to a group exceed the costs.
 Optimal size – the size at which the net benefits received by its members are maximized; the observed group however can be ____ than the optimal size

Answer 20

larger

Question 21

 Sexual selection is a process in which individuals with certain characteristics gain an ____ over others of the same sex solely with ____ to ____ ____ .
 Sexual selection can be considered competition for gametes.

Answer 21

advantage

respect to mating success.

Question 22

 Competitive males and choosy females result from greater female investment in offspring;

Answer 22

the reverse occurs when there is greater male investment in offspring.

Question 23

 In species in which ____ invest more in their offspring than ____ do, we would expect ____ to be choosy and ____ to compete for the right to mate with females.
 Since ____ invest relatively little per offspring produced, we would expect that ____ could produce more offspring during their lifetime than ____ could.

Answer 23

females
males do
females
males

males
males
females

Question 24

direct benefits

Answer 24

nuptial gifts
gifts of food, help in rearing the young, or access to a territory that has good nesting sites, abundant food, or few predators.

Question 25

indirect benefits

Answer 25

good genes
 The sexy sons hypothesis: females receive indirect genetic benefits through their sons, who will themselves be attractive to females and produce many grandchildren

Question 26

 The males that do the ___ job at copulatory courtship are the ones that get ___ and are ___ by females.

Answer 26

best
chosen
favored

Question 27

 Mating system refers to the number of mating partners that males or females have and the pattern of parental care.

Answer 27

 Mating systems can vary among closely related species and among individuals within a population of a single species.

Question 28

 Monogamy -

Answer 28

male mates with one female. Both parents care for young. Not much variation in reproductive success.

Question 29

 Polygyny –

Answer 29

male mates with multiple females. Male may control females directly or indirectly. Females care for young. In polygynous mating systems there are “floater” males. “Polygyny occurs if environmental or behavioral conditions bring about the clumping of females, and males have the capacity to monopolize them.” Emlen & Oring (1977). There’s a dramatic variation in reproductive success for males.

Question 30

 Polyandry –

Answer 30

female mates with multiple males. Female may defend males directly or indirectly. Males care for young. In polyandrous mating systems there are “floater” females. There’s a dramatic variation in reproductive success for females.

Question 31

 Promiscuity –

Answer 31

both males and females mate with multiple partners. Anything goes.

Question 32

 A general schema of the determinants of a mating system:

Answer 32

 Low potential for polygyny: females are spread evenly throughout the environment.
 High potential for polygyny: females clump together in some regions of the environment.

Question 33

 Pick a point on the monogamous female curve. The distance to the right to intercept the bigamous female curve is the polygyny threshold, i.e., the habitat quality increase required to make it worthwhile for the female to share a mate.

Answer 33

 Polygyny threshold is the minimum difference in quality of habitat held by males in the same general region sufficient to make bigamous matings by females favored by natural selection.

Question 34

 Kin selection exposes the selfish nature of ___; helping kin can ____one’s inclusive fitness (direct plus indirect fitness)
 Hamilton’s Rule: rB > C
 Relatedness * (Benefits to recipient) > (Costs to altruist)

Answer 34

altruism

increase

Question 35

 Relatedness
 r – introduced by Sewell Wright as a measure of ___
 Each connector is mediated by a ___(i.e., half of the donor genes to the recipient).
 Niece-Aunt – r = [1/8+1/8] = ¼

Answer 35

consanguinity

gamete

Question 36

 Eusociality in Diploid Organisms
 For most individuals in the colony the benefits to helping the ____ outweigh the costs of sacrificing their own reproduction
 rB > C

Answer 36

queen

Question 37

 Eusociality in Haplodiploid Organisms
 For most female individuals in the colony the benefits to helping the queen ____ ____ outweigh the costs of sacrificing their own reproduction
 rB > C

Answer 37

rear sisters

Question 38

 Haplodiploid sex determination - males (haploid) develop from ____ eggs; females (diploid) develop from ____ eggs.

Answer 38

unfertilized

fertilized

Question 39

 Father is related to each daughter with r=__
 Daughter is related to her father (or mother) with r=__
 A female is related to her sister with r=__
 Accordingly, it pays a sister to help her sister more than her own offspring.

Answer 39

1
1/2
3/4