AP Bio Vocab 7

evolution

descent of organisms from common ancestors with the development of genetic and phenotypic changes over time that make them more suited to the environment

natural selection

mechanism of evolution caused by environmental selection of organisms most fit to reproduce; results in adaptation to the environment

species

group of similarly constructed organisms capable of interbreeding and producing fertile offspring; organisms that share a common gene pool; the taxon at the lowest level of classification

allele frequencies

the proportion of a specific allele within a population; used to study genetic variation and evolution within a population

population

group of organisms of the same species, occupying a certain area and sharing a common gene pool

genotype frequencies

the proportion of individuals within a population that possesses a single genotype; indicates how common a particular genetic combination is within a group of organisms

speciation

origin of new species due to the evolutionary process of descent with modification

fitness

ability of an organism to reproduce and pass its genes to the next fertile generation; measured against the ability of other organisms to reproduce in the same environment

artificial selection

intentional breeding of certain traits, or combinations of traits, over others to produce a desirable outcome

convergent evolution

similarity in structure in distantly related groups generally due to similar selective pressures in the environments

adaptation

organism's modification in structure, function, or behavior suitable that better suits the environment

mutation

alternation in chromosome structure or number and also an alternation in a gene due to a change in DNA composition

genetic drift

mechanism of evolution due to random changes in the allelic frequencies of a population; more likely to occur in small populations or when only a few individuals of a large population reproduce

bottleneck effect

type of genetic drift; occurs when a majority of genotypes are prevented form participating in the production of the next generation as a result of a natural disaster or human interference

founder effect

cause of genetic drift due to colonization by a limited number of individuals who, by chance, have different genotype and allele frequencies than the parent population

migration

regular back-and-forth movement of animals between two geographic areas at particular times of the year

random mating

a reproductive strategy where individuals choose mates purely by chance, without any preference based on their genotypes or phenotypes

extant organism

species, or other levels of taxa, that are still living

extinct organism

total disappearance of a species or higher group

fossil

any past evidence of an organism that has been pressured in the Earth's crust

vestigial structure

remains of a structure that was functional in some ancestor but is no longer functional in the organism in question

homologous structure

in evolution, a structure that is similar in different types of organisms because these organisms are derived from a common ancestor

heterozygote advantage

situation in which individuals heterozygous for a trait have a selective advantage over those who are homozygous dominant or recessive

analogous trait

structure that has a similar function in separate lineages but differs in anatomy and ancestry

eukaryote cell

type of cell that has a membrane-bounded nucleus and membranous organelles

prokaryote cell

lacking a membrane-bounded nucleus and organelles

pathogen

disease-causing agent such as viruses, parasitic bacteria, fungi, and animals

endosymbiotic theory

explanation of the evolution of eukaryotic organelles by phagocytosis of prokaryotes

derived characteristics

structural, physiological, or behavioral trait that is present in a specific lineage and is not present in the common ancestor for several lineages

punctuated equilibrium

a theory that proposes species remain relatively stable for long periods of time, with occasional bursts of rapid evolutionary change, leading to the appearance of new species in the fossil record

gradualism

theory that evolutionary changes occur slowly and steadily over a long period of time, with small genetic changes accumulating to bring about large changes

adaptive radiation

rapid evolution of several species of a common ancestor into new ecological or geographical zones

sympatric radiation

origin of new species between populations that are separated geographically

prezygotic mechanisms

anatomical or behavioral differences between two species that prevents the possibility of mating

postzygotic mechanisms

anatomical or physiological difference between two species that prevents successful reproduction after mating has taken place

reproductive isolation

the prevention of interbreeding between two different species

gene flow

sharing of genes between two populations through interbreeding

retrovirus

RNA virus containing the enzyme reverse transcriptase that carries out RNA/DNA transcription

prophage

a bacteriophage genome that is integrated into the circular bacterial chromosome or exits as an extrachromosomal plasmid within the bacteria cell

lysogenic cycle

bacteriophage life cycle in which the virus incorporates its DNA into that of a bacterium; occurs preliminary to the lytic cycle

prion

infectious particle consisting of protein only and no nucleic acid

lytic cycle

bacteriophage life cycle in which the virus takes over the operation of the bacterium immediately upon entering it and subsequently destroys the bacterium

bacteriophage

virus that infects bacteria

divergent evolution

the process where two or more related species evolve into increasingly dissimilar forms, often due to adapting to different environments or ecological niches, resulting in the development of unique traits and potentially leading to speciation

allopatric speciation

occurs when a population is geographically isolated, leading to the evolution of distinct species due to reduced gene flow and divergent selection pressures