lecture 4 - competition Flashcards
what is competition?
Some individuals have more offspring than others – drives the evolutionary chains
what did Malthus cofound?
the discipline of demography - study of pops
- he had a profound influence on Darwin
what is an exponential function?
where the rate of change increases
-Accelerating curve that goes upwards – amount it goes up with is more than the previous
what would happen if populations were left unchecked?
they should follow this exponential curve
- there has to be something going on which stops this process so that we dont have an exponential increase in pops e.g. not everyone will reproduce to their full capacity
what is evolutionary change at a genotypic level?
An allele that confers a selective advantage increases in frequency relative to the alternative allele, more quickly if it is dominant (a), more slowly if it is recessive (b)
what is fitness?
property of an allele – how frequent it occurs over generations
Individuals with a particular allele which has a high reproductive success would have high fitness
what is the evolutionarily stable strategy (ESS)?
A behaviour that, once common in a population, cannot be out-competed by any alternative behaviour
what is an example of ESS?
Cub killing in lions – once evolved it will have a low fitness allele and wont pass it on
what is differential reproductive success?
only a subset of each generation become the ancestors of the next
- getting allelles into the next generation is to have offspring ourselves
what is collateral kin?
helping someone to have offspring e.g. giving resources, babysitting etc
what is kin selection - Hamilton’s rule?
c <r x b - I should help when the benefit is greater than 2
- any beh that meets this equality will be met due to natural selection
- this helps us to understand how things can evolve
what is explained by kin selection?
alloparenting, kin directed helping, multi-cellularity and euoscociality
what is alloparenting?
parenting by others than the parents e.g. family, siblings etc
what is kin-directed helping?
by making these calls can understand they may be more attacked by a predator – produce calls a lot when offspring are present and when siblings and parents are present – by saving lives of parents they can go on to have more offspring – siblings – 50% of genes
what is multi-cellularity?
life for most cells in the body is a rubbish deal – get to reproduce by mitosis and they never get the opportunity to be passed onto the next generation
what is eusociality?
Idea that some insects have a cast on individuals who don’t reproduce
Eusocial insects – particular individuals who focus on certain tasks e.g Naked mole rat – live underground – highly related to one another, breeding queen who gives the offspring
