Chapter 6 Flashcards
1
Q
Four issues of habitat and space
A
- where to live?
- defend your turf?
- stay, put, or leave, even temporarily?
- decisions about the use of space come with costs
2
Q
What is the main cause of species’ decline?
A
habitat distruction
3
Q
WHat are preferred habitat?
A
those where breeding success is the best
4
Q
How do Male black warblers have preferred habitats?
A
- settles on edges of streams in deciduous forests first
- this is the preferred habitat
- Later settlers choose mixed conifers away from water
- average number of offspring is the same for both
- settles on edges of streams in deciduous forests first
5
Q
What is the ideal free distribution theory (2), and what does it predict?
A
- helps us predict what animals should do when choosing between native habitats of different quality when there is competition for space and food; key prediction is individuals will settle on sites where reproductive success is maximized
- if individuals were free to distribute themselves in relation to resource quality and competition intensity, there will come to a point where competition is so intense that there is higher fitness settling in lower-ranked habitats with fewer occupants
6
Q
How do blackcaps exhibit IFD?
A
- nesting blackcaps were 4x higher in the preferred habitat
- habitat decision based not only on vegetation and insect productivity but also on the intensity of intraspecific competition
7
Q
What does the IFD require?
A
requires that individuals must move about to be able to evaluate the quality of different habitats
8
Q
How do red-winged blackbirds exhibit the IFD?
A
females would choose lower-quality territories when higher-quality territories are filled with nesting females
9
Q
How do red knots exhibit the IFD?
A
- when wintering, knots move about several large tidal areas in ways that equalize individual food intake
- eat small snails in varying densities in the mud
- equal food intake by shifting sites, depending on mud snail availability and red knot density
10
Q
What discourages free movement of individuals?
A
by territorial males that try to monopolize high-resource areas
11
Q
What is a home range?
A
where a species occupies various activities
12
Q
What is a territory?
A
being able to use resources on a territory without interference from others
13
Q
How do collared lizards benefit from territoriality?
A
- inherit territory when the older male dies
- more opportunities to court females than males without the good fortune of a neighbor’s death
14
Q
How do chimpanzees exhibit territoriality, and the benefit?
A
- males patrol the boundaries of their territory
- if they encounter a smaller group from another troop, they may kill and attack them
- maybe able to increase their territory
15
Q
How must territoriality be adaptive?
A
- benefits of territory expansion must be balanced against the costs of aggression
- cost: time and energy spent attacking
16
Q
How do yarrow’s spiny lizard exhibit the adaptiveness of territoriality and the cost?
A
- non-territorial males were made territorial in an experiment by giving testosterone
- when released, they patrolled more, did more push-up displays, and used more energy than control males (no testosterone)
- enhanced males used up energy reserves and diet at an earlier age
- in nature, males are not aggressive, only during the mating period
- no resources to defend outside of breeding season
17
Q
What can we predict if territoriality is costly?
A
peaceful coexistence on the home range should evolve when the benefits of owning resources don’t outweigh the costs of monopolizing it
18
Q
How do pseudoscorpions adjust aggressiveness?
A
- disperse from dying trees to new ones
- when dispersing, the ride on the elytra of large harlequin beetles
- they can mate on trees and on beetles
- larger males only become territorial when on a beetle
- beetle is smaller and more defensible than a tree
- males may have a virtual harem of females traveling with them to a new home
19
Q
How do American redstarts exhibit cost-effective territoriality?
A
- males occupy black mangrove forests along the coasts
- females are likely found inland secondary-growth forests
- competitively excluded by the males
- older, heavier males attack younger males, and intruding females
- birds in preferred territories retain weight over winter, unlike excluded birds
- territorial males leave wintering grounds earlier than excluded birds
- their higher energy reserves allow that
- early male arrivals have a reproductive advantage by getting the best territories and access to females
20
Q
How do arctic ground squirrels display cost-effective territoriality?
A
- males compete for meadow patches
- females live in the same meadows and can mate with multiple during the breeding season
- territorial males don’t monopolize access to females
- even though females can mate several times, the first male is almost always the one to fertilize her eggs
- territorial males would be the most likely to mate first
21
Q
What is the evolution stable strategy?
A
- arbitrary rule for resolving conflicts between residents and intruders
- resident always wins
22
Q
What will be the result of the ESS?
A
- if all competitors adopted this, mutants for a different behavioral strategy would not spread by natural selection
- mutant that did challenge would have a chance of being injured by a better fighter
- intruders that give up immediately would never be injured
- allows the “resident always wins” to persist
23
Q
How do speckled wood butterflies support the ESS?
A
- territorial males defend sunlit patches on the forest floor
- territorial males mate more frequently
- territorial males always quickly defeat intruders, who usually leave quickly
- if resident males are removed, they lose when trying to reclaim territory in experiments
24
Q
How did speckled wood butterflies disprove ESS?
A
- in repeated experiments, butterflies were put in a less stressful environment
- when released, males engaged in prolonged fights, and original residents often won
- resident male does not always win
25
What usually decides who wins in a territory?
- winners win due to having an edge in physical combat
- territory holders are relatively large and strong
26
How do red-shouldered widowbirds win territories without being bigger?
- males with bigger and redder shoulder patches are more likely to hold territories
- territorial males don’t differ in body size
- in experiments, larger patches almost always dominate floaters
- even when patches were painted black, they would still dominate
27
How do male damselflies win for territory?
- territorial males aren’t always larger, but those that win aerial contests almost always have higher fat content
- war of attrition
- winter outlasts loser
28
Why might older individuals win or defend territory better than younger, fitter individuals?
- may be due to individuals valuing the same resources differently
- resident has greater payoff keeping a territory than newcomer gain
- resident’s value is linked to familiarity with a location
- we can predict that when a resident is removed, newcomer's ability to fend off intruders is related to how long he occupied the site
- supported by birds, insects, and fishes
29
What is the payoff asymmetry hypothesis?
- contests between an ex-resident and his replacement will become more intense the longer the replacement has been there
- the longer the replacement has been there, the more value the site has to him
30
How do tarantual hawk exhibit the payoff asymmetry hypothesis?
- when males are removed from a territory, it will be claimed quickly
- if ex-resident is kept away longer, a more intense battle occurs for the original territory
31
How do European robins exhibit resource holding power?
- when replacing replacements, ex-residents beat newcomers but not original replacement
- contests were decided by how long the replacements occupied the territory
32
What is the dear enemy effect?
established territory holders have a greater pay off to hang on may be related to relationships with neighboring competitors
33
How do African lizards exhibit the dear enemy effect?
- charges unfamiliar lizard from further distances and longer periods than they would familiar neighbors
- once they are acquainted, they no longer have to expend time and energy cahsing
34
Why might it be costly for newcomers regarding the dear enemy effect?
newcomers must expend more time and energy to establish themselves with the neighbors
35
How do stephens kangaroo rats exhibit the dea enemy effect?
when creating new breeding populations, it was best to reintroduced individuals with prior experience
36
What are dispersal costs? (2)
- need to secure energy for travel
- risk of predation when traveling to unfamiliar areas
37
How do ruffed grouse exhibit cost of dispersal?
- tracked movement of individuals and find those that stopped moving
- those that stopped moving after 8 hours were likely dead
- some birds remain in the same area for months, while others moved a lot between different locations
- 3x risk of predation for those that move
38
Why might animals leave home?
social behavior and ecology of a species
39
Why might belding's ground squirrel leave home?
young male dispersed further to establish burrows than young females
dispersal of juveniles may reduce chance of inbreeding
40
How do prarie voles prevent inbreeding?
- preference for mating with strangers
- decreases chance of reproducing with litter mates
41
Why do male spotted hyenas disperse? (3)
- young males leave natal clans and disperse
- females prefer recent male recruits, and avoid male clans
-losers may find it beneficial to move elsewhere and avoid conflicts
42
Why don't female spotted hypenas disperse?
females don’t disperse as they may form alliances and receives assistance from mothers and benefit from mother’s social status
43
What is migration?
dispersal that involves movement away from and back to the same location
44
Three examples of migration
- ruby-throated hummingbird
- flies from Canada to Panama
- Bar-tailed godwit
- Alaska to New Zealand
- Sooty shearwater
- entire Pacific
- new Zealand to japan, Alaska, or California, and back to new Zealand
45
How did migration evolve?
sedentary species were ancestral to migratory species
46
How did migration evolve in tropical bird species?
- tropic bird species that have short-range migration
- three-wattled bellbird
- migrate from Costa Rica to Nicaragua (200 km)
- short-ranged migration were found in 9 tropic families
- 7 of these have long-distance migrants
- both ranges of migration suggest short-range preceded long range
47
How did thrushes evolve migration?
- 5 of 12 species are migratory
- 7 are sedentary to Mexico and South America
- ancestor is likely from Mexico and South America
- migratory behavior evolved 3 different times
