AP Bio 7A Vocab

LaMarck

French naturalist who proposed that evolution resulted from the inheritance of acquired characteristics (1744-1829)

acquired characteristics

traits altered by an individual organism during its life

Darwin

English natural scientist who formulated a theory of evolution by natural selection (1809-1882)

Galapagos Islands

Chain of islands near South America where Darwin developed his theory of natural selection by studying the unique life there.

Galapagos Finches

beak shape is determined by the availability of food

variation

Any difference between individuals of the same species.

competition

the struggle between organisms to survive in a habitat with limited resources

adaptations

traits that improve an individual's ability to survive and reproduce

survival of the fittest

A natural process resulting in the evolution of organisms best adapted to the environment.

peppered moth

example of natural selection caused by pollution

disruptive selection

favors individuals at both extremes of the phenotypic range

stabilizing selection

Natural selection that favors intermediate variants (center) by acting against extreme phenotypes

directional selection

occurs when natural selection favors one of the extreme variations of a trait

artificial selection

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

microevolution

evolutionary change within a species or small group of organisms, especially over a short period.

gene pool

All the genes, including all the different alleles for each gene, that are present in a population at any one time

alleles

different versions of a gene

gene flow

movement of individuals and alleles in and out of population; increases variation in the population

genetic drift

random change in allele frequencies that occurs in small populations; decreases variation in the population

mutations

create variation in a population by changing the DNA sequence

founder effect

genetic drift that occurs after a small number of individuals colonize a new area

bottleneck effect

Genetic drift resulting from the reduction of a population, typically by a natural disaster, such that the surviving population is no longer genetically representative of the original population.

Hardy-Weinberg equilibrium

condition that occurs when the frequency of alleles in a particular gene pool remain constant over time

chi squared formula

sum of (observed-expected)^2/expected