L1- introduction Flashcards
what is the adaptationist approach
adaptationist approach incorporates evolutionary theory, behaviour and ecology
it weighs up costs and benefits of a behaviour to determine its adaptive significance, what is the evolutionary value (function) of a particular trait
how do weavers socially organise and why?
- looked into the social organisation in weaver birds
- they vary in how groups socially organise and their colour. Some live in large colonies of 50/100 nests of pairs, some live solitary.
- Found that variation in weaver bird organisation was driven by food they ate,
-birds that live in forests and feed of insects are solitary (their own territory) tend to be monogomous
species that live in grassland and feed on seeds are highly social, with colonies of nests, more likely to be polygamous.
found this reasoning explained social organisation in primates such as goldon lion tamarin, but what is the cause of this?
how do you study interspecific v intraspecific variation
comparative analysis (usually phylogenitic trees)- interspecific variation
study of individuals (observation or experimental studies in field/lab)- intraspecific variation
what is the lekking system of ruff birds
- intraspecific
independent males, compete for territory- dark ruff neck, increased body size and most aggressive
satellite males, not territorial, try and intercept females - grey ruff, bigger then fader smaller then territorial, big testes too ejaculate lots of sperm
fader males- female mimics - mimic looking like female, sneak copulations to visiting females, smallest and least aggressive
found there is a simple genetic determination to these, in a supergene.
how is sexual selection show in field studies of long tailed widow bird
long tailed widow bird found that the more elongated the tail the increased mating they had
what level does selection take place on
genes and individuals
individuals survive, reproduce and die, and consequence is that gene frequencies in population change - natural selection acts on genes that produce organisms designed to maximise their evolutionary fitness
why is group selection unliekly
unlikely to operate in nature because it is vulnerable to exploitation by selfish individuals
what causes conflict
individual success often comes at the expense of another, so intra and inter specific competition leads to conflict, even within families (pic)
if conflict is so common why is there cooperation
cooperative investment allows benefits to be shared, and costs are born individually
groups of co-operators out-compete none-co-operators
but free riders do better then co-operators within groups
what is the tragedy of the commons
when there are shared benefitds (ie public good) that individuals contribute too, there will be a temptation to cheat or free load
