Unit 9 vocab

evolution

change overtime, process of modern organisms depending from ancient ones

fossil

preserved remains/traces of ancient organisms

artificial selection

selective breeding of plants and animals ro promote the occurrence of desirable traits in offspring

adaptation

heritable characteristics that increases an organism’s ability to survey and reproduce in an environment

fitness

how well an organism can survive and reproduce in its environment

natural selection

process by which organisms that are most suited to their environment survive and reproduce most successfully, also called survival of the fittest

biogeography

study of past and present distribution of organisms

homologous structures

structures that are similar in different species of common ancestry

vestigal structures

structure that is inherited from ancestors but has lost much or all of its original function.

analogous structures

body parts that share a common function, but not structure

hox genes

determines the location of body parts

species

population of physically similar, inbreeding organisms that do not inbreed with other such groups

population

group of individuals of the same species that mate and produce offspring

gene pool

all genes present in a population, including all alleles for each gene

allele frequency

number of times an allele occurs in a gene pool as a percentage of the total occurrence of all alleles for that gene in that gene pool.

single-gene trait

traits controlled by one gene that has 2 alleles

polygenic trait

traits controlled by 2 or more genes

directional selection

form of natural selecting when individuals at one end of a distribution curve have a higher fitness that individuals at the middle or at the other end of the curve

stabilizing selection

form of natural selection in which individuals near the center of a distribution curve have higher fitness than individuals at either end of the curve

disruptive selection

natural selection in which individuals at upper and lower ends of the curve have higher fitness than individuals at middle of curve

genetic drift

random change in allele frequency caused by a series of chance occurrences that cause an allele to become more or less popular in a population

bottleneck effect

a change in allele frequency following a dramatic reduction in the size of a population.

founder effect

change in allele frequency due to the migration of a small subgroup of a population

genetic equilibrium

situation in which allele frequencies in a population remain the same

Hardy Weinberg principle

principle that states that allele frequencies in a population remain constant unless one or more factors cause those frequencies to change

sexual selection

when individuals select mates based of heritable traits (NOT in equilibrium)

gene flow

the movement of genes into or out of a population

speciation

formation of a new species

reproduction isolation

separation of a species or population so they no longer inbreed and evolve into two separate species

behavioral isolation

form of reproductive isolation in which 2 populations develop differences in courtship rituals or other behaviors that prevent them from breeding

geographical isolation

form of reproductive isolation in which 2 populations are separated by geographic barriers such as river, mountains, or bodies of water, leading to the formation of 2 separate subspecies

temporal isolation

form of reproductive isolation in which 2 or more species reproduces at different times

phylogeny

study of evolutionary relationships among organisms

clade

evolutionary branch of a cladogram that includes a single ancestor and all its desendants

cladogram

diagram depicting patters of shared characteristics among species

derived character

trait that appears in recent parts of a lineage but not in its older members

macroevolutionary pattern

change in anatomy, phylogeny, and behavior that takes place in clades larger than a single species

background extinction

extinction caused by slow and steady process of natural selection

mass extinction

event during which many species become extinct during a relatively short period of time

gradualism

the evolution of a species by gradual accumulation of small genetic changes over long periods of time

punctuated equilibrium

long stable periods interrupted by brief periods of rapid change

adaptive radiation

process by which a single species or small group of species evolves into several different forms that live in different ways

convergent evolution

process by which unrelated organisms independently evolve similarities when adapting to similar environments

coevolution

process by which 2 species evolve in response to changes in each other overtime