5 causes of microevolution
migration of animals
causes genetic mixing across regions reduce differences between populations
mutation changes DNA sequence
changes amino acid sequence (especially in third base) changes protein? changes structure? changes function? changes in protein may change phenotype and therefore change fitness
natural selection
differential survival and reproduction due to changing environmental conditions
genetic drift
effect of chance events in small populations -founder effect -bottleneck
human evolution today
gene flow in human populations is increasing today transferring alleles between populations
gene flow (migration)
movement of individuals and alleles in and out of populations ex seed and pollen distribution by wind and insect
mutation and variation
mutation causes variation new mutations are constantly appearing
5 causes of microevolution
mutation, gene flow, non-random mating, genetic drift, selection
non random mating
sexual selection
bottleneck effect
when a large population is drastically reduced by a disaster -famine, natural disaster, loss of habitat -resulting population may not accurately represent original gene pool ex. cheetahs all cheetahs share a small number of alleles less than 1% diversity as if all cheetahs are identical twins
founder effect
a new population started by a small group of individuals -rare traits may be at high frequency, common may be missing -skews gene pool of new population -not accurate reflection of original population ex. albino deer Seneca Army Depot
2 bottlenecks
10,000 years ago ice age last 100 years- poaching and loss of habitat
