Bio– Evolution

species altered overtime due to environmental influences

individuals in a species are different

usually more individuals in an environment than can be supported, leads to competition for resources

traits that make an organism MORE LIKELY to survive & reproduce

how well an organism can survive and reproduce in their environment– better adaptions=greater fitness

individuals w/ greater fitness are more likely to survive & therefore reproduce, passing their adaptations to future generations

trait controlled by one gene

trait controlled by 2+ genes

“average phenotype” becomes more common overtime

1 “extreme” phenotype becomes more common overtime

both “extreme” phenos become more common overtime, may lead to speciation

a population must not be evolving– when disturbed, a population is evolving

allele frequency should remain constant in a population unless “disturbing factors” cause them to changeto

1. be large

2. randomly mate

3. not migrate

4. not have new mutations

5. not experience natural selection

p+q=1 (for allele frequencies)

p=frequency of dominant allele, q=recessive

p^2+2pq+q^2=1 (for genotype frequencies)

p^2=frequency of homoY

when mate selections are based on traits, not random

changes in allele frequencies due to chance events

when a few individuals migrate and establish a new, reproductively isolated population

when a sudden unexpected event causes a sudden, drastic reduction in population size

migration of individuals in/out of a population

very low rates, doesn’t usually alter evolution unless paired with another mechanism

all living things are related to some extent via common ancestors

each generation of a population is slightly different than the previous

any heritable change in a population across the span of many generations

species develop more different traits over time as a result of different environmental changes/pressures

species develop more similar traits over time due to shared environmental changes/pressures

species “pressure” one another into evolving due to close interactions

1. direct observations of populations

2. anatomy

3. embryology

4. molecular biology

5. fossils

6. biogeography

similar in structure & SOMETIMES function, inherited from common ancestor

similar function but not structure, no common ancestor

features leftover from ancestors that no longer serve a purpose

a population whose members have the potential to interbreed in the WILD and produce FERTILE offspring

divergent evolution of an ancestral species into new descendant species

species unable to interbreed for some reason

can’t reproduce due to different reproductive organs

can’t reproduce due to different courtship rituals

can’t reproduce due to sperm & eggs being unable to fertilize

can’t reproduce due to the presence of a physical barrier

can’t reproduce due to living in different environments and not interacting

can’t reproduce due to different times of year that they do so

something prevents species from breeding

something prevents offspring from surviving/being able to reproduce at all

evolution occurs through slow, consistent changes that add up over a long period of time reflecting a slowly changing environment

evolution occurs due to sudden, rapid changes reflecting a rapidly changing environment

species of interest on a cladogram

place where two species’ ancestry meets on a cladogram

most recent common ancestor

trait closest to cladogram root, present in all species on cladogram

least closely related to other species on cladogram

group of organisms & their MRCA

traits developed after ancestral trait, possessed by SOME species on cladogram