Fitness Flashcards
what is fitness
the relative probability of survival and reproduction of a given genotype
what decides someones fitness
vaires according to environmental condissions
sickle cell, differences between those who are homozygotic and those who are hetero zygotic
homo - unwell, more liekly to get anaemia, worse symptoms
heterzygotes - less likely to get malaria so is advantageous in malarial zones
so this is possibly why unfit alleles remain
genetic basis of sickle cell?
mutation causing change in amino acid - alters structure of Hb
(CRISPR is a potential treatment for this)
levels selection can occur at
- species
- groups
- families
- individuals
- genes
know that there are diff view on what level selection occurs at, with some people taking multi level approach
what’s an example of ‘hitchhiking genes’
genes being physically close to each other and on same DNA chain meaning they end up being swept up when another gene is being selected for
e.g. deletrious gene = cancerous gene
what is sexual selection
natural selection arising through preference by one sex for certain characteristics in individuals of the other sex.
why might some maladaptive charateristics still be selected for?
sexual selection (until natural selection takes over if theres a strong selec pressure)
why might animals mate with others with certain charac, even if they seem maladaptive?
may have underlying good genes
e.g. peacock w/ colours
femal may think it shows that it has good health and no parasites
and that it’s male way of showing fitness
how did darwin explain neuter insects
insects that are sterile - e.g. in bees only queen bee reproduces
selection on family level
what is altruism
beh of an animal that benefits another at its own expense
what are the 2 types of fitness
darwinian/direct fitness = survival and production of offspring
inclusive fitness = direct fitness + indirect fitness (fitness of related offspring)
aka kin selection
what is hamilton’s rule?
natural selc of genes that lead to social actions via the sharing of these genes between performer and recipient
ie rb>c
what is rb>c
c = the cost of being altruistic
b = benefit to someone by recieving altruism
r= degree of relatnedness
as long as rb>c then altruism occurs
how might altruistic effects occur between individuals
might respond to individuals with similar genotype e.g. detected by smell
more liekly when relatedness is high e.g. in social insects