Evolution Flashcards
5 agents of evolutionary change
mutation and variation, gene flow, non-random mating, genetic drift, and natural selection
mutation and variation
random genetic changes
gene flow
movement of alleles from one population to another, it reduces differences in populations
non-random mating
individuals select their partner
genetic drift
gene frequency is unstable due to small size of population
natural selection
any adaptation an individual takes in order to better fit into its environment
founder effect
small group splinters off and starts a new colony
bottleneck effect
some factor (disaster) reduces population to small number and then population recovers and expands again
sources of variation?
mutation
evolutionary fitness
survival and reproductive success
5 conditions that must be met by a population in hardy weinberg equilibrium
- population size is large
- random mating
- no mutations
- no genes input from other sources
- no selection
what upsets the hardy weinberg equilibrium?
any agent of evolutionary change
what can changes of allele frequency over time tell us?
it can tell if an agent of evolutionary change is at work
describe how the heterozygote genotype helps to maintain the recessive alleles in a population
it carries the recessive allele so it may stay present in a population
difference between Lamarck’s theory and Darwin’s theory
Lamarck: individual acquire adaptations during their life
Darwin: the adaptations were handed down through the fittest to reproduce
explain the observations on Darwins voyage helped him formulate his theory
the finches Darwin observed adapted to best fit their environment
Darwins conclusion of how the finches became so diverse on the Galapagos Islands
they became more diverse to better fit their environments
artificial selection
human selects for or against a certain trait
covergent
not closely related and similar traits allow them to survive
parallel evolution
completely separate habitats but are similar
sexual selection
favors certain traits; males most fit
directional selection
when it favors one side of a curve
disruptive selection
the ends are favored
stabilizing selection
highly favored on one genotype
allopatric speciation
species that evolve the same time but are geographically separated
sympatric speciation
species that evolve at the same time and same area
geographic isolation
physical barrier w 2 species on either side
reproductive isolation
when two species can’t reproduce together
what can result from isolated populations?
speciation
pre-zygotic examples
behavioral- different mating rituals
temporal- breed at different times
mechanical- bodies can’t reproduce together
post-zygotic
hybrid inviability- zygote dies
hybrid sterility- surviving hybrid animal can’t reproduce
gradualism
slow changes overtime
punctuated equilibrium
rapid changes when needed
explain what is meant by “evolution is no goal-orientate”
evolution occurs for survival
describe how biologist can use info from DNA sequences can be used to develop phylogenetic trees
the closer related the DNA the closer related the organism
biological species concept
can breed together or not
offspring is fertile
