1 Flashcards
what is NS?
process where individuals of different genotypes make a differential contribution of offspring to the next gen
how is the genetic composition of the population changed?
genetically different individuals leave different numbers if offspring in future gens
what is adaptation?
evolutionary change resulting from NS
what is regarded as a unit of selection?
genes or interacting groups of genes/individuals
when NS acts on genes what is produced?
organisms designed to maximise their inclusive fitness
due to NS and the aim to maximise fitness what do we expect genes and individuals to be?
- what does this result in?
selfish rather than cooperative
- conflict as individuals maximise their own fitness at the cost of others fitness
what did John Crook discover about the intensity of SS and pair bonding in birds? (2)
- what was predicting the social structure?
- in forests feeding on insects bird are more solitary with monogamous bonds
- in grasslands birds are more colonial with polygynous pair bonds
- food and predation
what predicts social structure in primates as well as weavers
food distribution
what is the adaptationist approach?
approach that assumes behavioural traits are a product of NS (rather than genetic drift)
What is the comparative approach?
- what must it account for?
approach to understand adaptation and how traits differ across species (interspecific)
- phylogeny
how do individuals differ in the male ruffs?
- dark male more successful than pale male
- satellite male is a female mimic
how do individuals differ in the male blue gills?
- large M produce large nests attractive to F
- medium M mimic F
- small M release sperm at the same time as large M during spawning
what is individual variation also known as?
intraspecific variation
give 3 examples of unusual behaviour as individual variation/intraspecific trait variation?
infanticide
male pregnancy
sexual cannibalism
in what species do males engage in sexual cannibalism and why?
redback spider- F eat males that offer themselves as a gift
in redback spiders what is the chance of the F rejecting the second male:
- if 1st M cannibalised
- if 1st M NOT cannibalised
- 67%
- 4%
what happens if the 2nd redback spider male mates for longer?
- what % available paternity + how long do the males mate for if cannibalised vs not cannibalised
more offspring gained
- NOT cannibalised: 11s mate + 45% paternity
- cannibalised: 25s + 95% paternity
are long term studies of marked individuals useful?
valuable but have drawbacks such as if long lived so need long timescales
what is the alternative to observations in the field/lab?
experimental studies in field/lab
give an example of an experimental study
long tailed widowbird tail length manipulation
- andersson 1982
- 1 group tail elongated
- 1 shortened
- 1 left alone
- 1 cut + restuck
- more mates with longer tail
what does the adaptationist approach:
- include
- used to understand
- evolves in the context of..
includes evolutionary theory to understand animal behaviour patterns which evolves in the context of the ecology of the organism
what can help determine a behaviours adaptive significance + evolutionary value?
weighing up costs and benefits
what is group selection vulnerable to?
selfish behaviour by individuals
sexual reproduction involves coop but what also is there?
sexual conflict
in a reproductive cooperative system where is there conflict (5)?
- M-M
- F-F
- F-M sexual conflict
- parent-offspring conflict (share of investment in broods)
- sibling conflict (over share of investment)
what is cooperation?
behaviour that benefits another individual and has been selected for due to beneficial effects on recipient
cooperation can be ubiquitous- what does this mean?
occurs at every biological organisation level
list 3 examples of coop
- queen termites: workers forage
- moorhens take turns incubating offspring
- shrimps clean gill rays of fish
what is the public goods game + who?
Rankin 2007
- some are cooperators contributing to public good
- if benefits of public good shared equally, free riders still benefit without contribution
- tragedy of the commons: public goods competed for in a social system
what are the 2 components of cooperative investment in public goods?
- BUT what does it cause + why?
- benefits shared
- costs borne equally
- BUT causes social dilemma as selfishness replaces coop
what is the tragedy of the commons? (4)
- public good/shared benefits competed for in social system
- temptation to cheat/defect/ non cooperate
- conflict over optimal investment as benefits shared + costs individual
- groups with coops outcompete non coops but non coops do better in groups
what does coop behaviour show about tragedy and what must there be?
not inevitable
- need mechanisms to resolve conflict between selfish interests
what are 5 solutions (+ define) to tragedy of the commons + conflict between selfish interests?
- group selection (differential extinction/proliferation of groups)
- kin selection (select beneficial traits on relatives fitness)
- reciprocity (help reciprocated later)
- mutualism (2 or more coop as gain net fitness benefit)
- manipulation (one is tricked into being altruistic to another)
is cooperation between kin?
yes + non kin
