Bio Lab 1 Flashcards
descent with modification
when divergent species share a common ancestor
mutation
creates variability for natural selection to act.
reproductive fitness
producing offspring with survivable traits
Darwin’s postulates
- variation due to genetics: individuals are different due to genetics
- overproduction: populations reproduce more than carrying capacity
- natural selection puts limits on survival and reproduction
- individuals that are fit will reproduce more and then the composition of the population will also change
**this results in adaptation
stabilizing selection
selects for average traits. variation is reduced
directional selection
shifts to one extreme
** results in adaptation mostly
disruptive selection
shifts to either extremes of graph. individuals at both extremes are highly fit and population variation is HIGH. bimodal pattern may result
positive natural selection force
adaptive traits increase the frequency of viable offspring
negative natural selection force
non-adaptive traits that decrease the frequency of viable offspring
sexual selection
weird flashy traits for reproduction develop
conditions for hardy-weinberg theorem
- no mutations occur
- random mating occurs
- no natural selection
- infinite population size
- no new genes flowing in
fixed allele
when p or q = 1
to calculate frequency of alleles
remember that BB is twice and that all alleles are double the total individuals but this gives you ALLELIC FREQENCY so no square rooting
when you mix the individuals
random mating
100 % negative selection
doesn’t fully take away the genotype, only decreases it. Ie -20% each generation (so 5 to eliminate)`
