Bio evolution unit

genuine hell

evolution

change in a population over time

natrual selection

organisms with favorable trait survive and reproduce more often

fitness

an organisms ability to survive and reproduce

selective pressure

an enviormental factor that affects survival and reproduction

resource

anything an organism needs to survive

fossils

preserved remains or traces of ancient organisms

relative dating

determining the age of the fossils by their position in rock layers

absolute dating

determining the exact age of fossils using radioactive isotopes

half life

the time it takes for half of a radioactive substance to decay

carbon-14

a radioactive isotope used to date once living organisms

biogeography

the study of where organisms live and how they are distributed

Molecular Evidence

DNA and protein similarities that show evolutionary relationships

embryological evidence

similarities in embryos that suggest common ancestry

Homologous structures

structures with similar anatomy due to common ancestry

analogous structures

structures with similar functions but different evolutionary origins

vestigal structures

reduced structures that have little to no current function

mutation

a change in dna that creates new alleles

gene flow

movement of genes between population through migration

genetic drift

random changes in allele frequencies

bottleneck effect

a type of genetic drift caused by drastic reduction in population size

s3xual selection

selection based on traits that attract mates

stabilizing selection

favors average traits and selects against extremes

disruptive selection

favors both extreme trait over the average trait

directional selection

favors one extreme trait

allele frequency

the proportion of an allele in a population

p+q=1

p=dominant allele frequency, q=recessive allele frequency

p² + 2pq + q² = 1

p²=homozygous dominant, 2pq=heterozygous,q²=homozygous recessive

4 Tenets of Natural Selection

variation, heredity, overproduction, reproductive advantage

Variation

Individuals within a population differ in their traits.

heredity

traits and genetic information are passed down from parents to their offspring

overproduction

More offspring are produced than can survive.

reproductive advantage

Individuals with beneficial traits survive and reproduce more.

5 mechanisms of microevolution

mutation, gene flow, genetic drift, natural selection, Nonrandom Mating(Sexual selection)

5 requirements for Hardy-Weinberg equilibrium

no mutations, no migration, large population size, random mating, no natrual selection

Darwins Observations

Species vary globally, species vary locally, species adapt to environment, Island species resemble mainland species.

Species vary globally

Different environments contain different species.

Species Vary Locally

Closely related species differ in nearby habitats.

Species adapt to their environment

organisms have traits suited to their surroundings

island species resemble mainland species

Island organisms are similar to nearby mainland organisms but have unique adaptations.

Law of superposition

In undisturbed rock layers, the oldest fossils are found in the lowest layers and the youngest fossils are found in the highest layers.