KA 2: evolution: drift and selection Flashcards
what is evolution?
the change over time in the proportion of individuals in a population differing in one or more inherited traits
during evolution, when do changes in allele frequency occur?
-non-random processes of natural selection and sexual selection
-random process of genetic drift
what does natural selection act on in populations?
genetic variation
variation in traits arises as a result of…
mutation
what is mutation?
the original source of new sequences of DNA
what can the new sequences from a mutation be?
novel alleles
what are most mutations?
harmful or neutral
in rare cases they may be beneficial to the fitness of an individual
populations produce…
more offspring than the environment can support
what happens to individuals with variations that are better suited to their environment?
they tend to survive longer and produce more offspring, breeding to pass on those alleles that conferred an advantage to the next generation
what does the selection result in?
the non-random increase in the frequency of advantages alleles and the non-random decrease in the frequency of deleterious alleles
what is sexual selection?
the non-random process involving the selection of alleles that increase the individual’s chances of mating and producing offspring
what does sexual selection lead to?
dimorphism
what can sexual selection be due to?
- male-male rivalry
- female choice
what is male-male rivalry?
large size or weaponry increases access to females through conflict
what is female choice?
involves females assessing the fitness of males