AP Bio 7.4-7.7

evolution is driven by…

random occurrences

the reduction of genetic variation can lead to what?

increased differences b/w populations of the same species

define genetic drift

random change in a particular allele’s frequency within a population

describe genetic drift (not def)

• nonselective (generally occurs in small pops)

• inc death rate + low reproductive rate

• natural catastrophe

define bottleneck events

refers to reduction in population size and genetic variation due to an environmental or human-caused change

may contribute to genetic drift

define the founder effect

• random process that reduces genetic variation within a small pop due to separation from a larger pop

• migration + geological events can isolate pop

• founder pop genetic makeup may differ from OG pop

define migration/gene flow

• movement of individuals b/w pops causing an exchange of alleles b/w pops

• introduces new genes into pops inc genetic var

• cont migration b/w pops dec genetic var bw pops over time

phenotype selection is based on…

environmental changes

what is the Hardy-Weinberg Equilibrium?

• model for describing + predicting allele frequencies in a nonevolving pop

what are the five conditions for a pop to be in HWE?

• large pop - no genetic drift

• absence of migration - no gene flow

• no net mutation

• random mating - no sexual selection

• absence of selection - no natural selection

id the different terms involved with HWE

• p = freq of dom allele

• q = freq of rec allele

• p² = freq of homozygous dom genotype

• q² = freq of homozygous rec genotype

• 2pq = freq of heterozygous genotype

what are the different types of evidence that add to our understanding of evolution?

geographical, geological, physical, biochemical, mathematical

why are fossil records significant?

they are incomplete but provide info abt earth’s history + world at that time

define homologous structures

variation in structure that was seen in common ancestor

ex. bone structure of human arms, cat legs, bat wings, dolphin fins

define vestigial structures

• reduced or obsolete structures w/ little to no purpose for the organism

• ex. leg bones in snakes

define analogous structures

• structures that evolved independently in diff species due to similar environmental conditions/selection pressures

what are example of some of the fundamental molecular and cellular features and processes that have been conserved?

• DNA + RNA are genetic info carriers through transcription, translation, + replication

• major genetic code features are shared by all modern living systems

• metabolic pathways to produce ATP are conserved across all currently recognized domains

what is structural evidence of eukaryotic common ancestry?

MB organelles, linear chromosomes, genes w/ introns, + nucleus

distinguish the prokaryotic genome

• singular circular chromosome

• contained in cytoplasm

• are small