Evolution

Evolution

Change in a species or population over time from simple to more complex

natural selection

the process whereby organisms better adapted to their environment tends to survive and produce more offspring

natural selection

The theory of its action was first fully expounded by Charles Darwin and is now believed to be the main process that brings about evolution

who was the scientist who’s theory about evolution was disproved

Lamarck

selective breeding or artificial selection

A practice where humans **artificially select** (they choose) which animals or plants have desirable traits and will breed with each other…their offspring have similar traits

evolution by natural selection #1

overproduction of offspring

evolution by natural selection #2

variation exists among offspring

evolution by natural selection #3

competition

evolution by natural selection #4

survival of the fittest or the best adapted

evolution by natural selection #5

the best-adapted pass on their genes to offspring

adaptation

a characteristic that improves an organism's chance of survival

fitness

an organism's ability to survive and pass on its genes to the next generation

Descent with Modification

as each generation of organism reproduces, small changes may be passed on over time

evidence of evolution #1

fossils

evidence of evolution #2

homologous structures

evidence of evolution #3

comparative embryology

evidence of evolution #4

comparative biochemistry

evidence of evolution #5

vestigial structures

population genetics

Measuring population change over time by looking at changes in allele frequencies

gene pool

The collection of all the alleles for every trait in a population

what do allele frequencies add up to?

1

genetic drift

evolution can occur in a population for reasons other than natural selection…allele frequencies will change…typically with a small population

founder’s effect

When a small number of individuals are isolated and re-populate a new area…their new allele frequencies don’t represent the original population

bottleneck effect

ccurs when a disaster kills a lot of a population…in the survivors, their new allele frequencies don’t represent the original population

genetic equilibrium

If there are no mutations, no new genes introduced, no selective mating, no natural selection, and no genetic drift, a population will be at

species can be reproductively be isolated by #1

geographic isolation

species can be reproductively be isolated by #2

temporal isolation

species can be reproductively be isolated by #3

behavioral isolation

endosymbiotic theory

Eukaryotic cells developed from prokaryotic cells that lived together in a symbiotic relationship

behavioral isolation

When two populations are capable of interbreeding but don’t since they have differences in reproductive strategies that involve behavior

temporal isolation

time of day or season when two populations mate differs

geographic isolation

a physical, geographic barrier isolates two populations