AP Biology: Evolution Flashcards

8594974593	homologous structures	structures in different species that are similar because of common ancestry	0
8594974594	vestigial structures	remnants of features that served important functions in the the organism's ancestors	1
8594974595	convergent evolution	the independent evolution of similar features in different lineages	2
8594974596	Hardy-Weinberg	the frequencies of alleles and genotypes in a population will remain constant from generation to generation, provided that only Mendelian segregation and recombination of alleles are at work	3
8594974597	gene pool	the aggregate of all of the alleles for all of the loci in individuals in a population	4
8594974598	population	a group of individuals of the same species that live in the same area and interbreed, producing fertile offspring	5
8594974599	natural selection	a process in which organisms with certain inherited characteristics are more likely to survive and reproduce than are organisms with other characteristics	6
8594974600	genetic drift	changes in the gene pool due to random events	7
8594974601	founder effect	when a individuals become isolated from a larger population, this smaller group may establish a new population whose gene pool differs from the source population	8
8594974602	bottleneck effect	when there is a severe drop in population size, certain alleles may be overrepresented among the survivors, others may be underrepresented, and some may be absent altogether	9
8594974603	gene flow	the transfer of alleles into or out of a population due to the movement of fertile individuals or their gametes	10
8594974604	directional selection	when conditions favor individuals exhibiting one extreme of a phenotypic range, thereby shifting the frequency curve for the phenotypic character in one direction or the other	11
8594974605	disruptive selection	when conditions favor individuals at both extremes of a phenotypic range over individuals with intermediate phenotypes	12
8594974606	stabilizing selection	acts against both extreme phenotypes and favors intermediate variants	13
8594974607	sexual selection	a form of natural selection in which individuals with certain inherited characteristics are more likely than other individuals to obtain mates	14
8594974608	sexual dimorphism	marked differences between the two sexes in secondary sexual characteristics, which are not directly associated with reproduction or survival (differences in size, color, ornamentation, and behavior)	15
8594974609	diploidy	the state of being diploid, that is having two sets of chromosomes	16
8594974610	heterozygote advantage	when individuals who are heterozygous at a particular locus have greater fitness than do both kind of homozygous	17
8594974611	frequency-dependent selection	fitness of a phenotype declines if it becomes too common in the population	18
8594974612	speciation	the process by which one species splits into two or more species	19
8594974613	microevolution	changes over time in allele frequencies in a population	20
8594974614	macroevolution	the broad pattern of evolution over long time spans	21
8594974615	species	a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring- but do not produce viable, fertile offspring with members of other such groups	22
8594974616	reproductive isolation	the existance of biological barriers that impede members of two species from producing viable offspring	23
8594974617	hybrids	offspring that result from interspecific mating	24
8594974618	prezygotic barriers	impede mating or hinder fertilization if mating occurs (five types: habitat, temporal, behavioral, mechanical, gametic)	25
8594974619	post zygotic barriers	prevents hybrid zygote from developing into a viable fertile adult through reducing hybrid viability, reducing hybrid fertility, or hybrid breakdown	26
8594974620	allopatric speciation	gene flow is interrupted when a population is divided into geographically isolated subpopulations	27
8594974621	sympatric speciation	speciation occurs in populations that live in the same geographic area (usually occurs due to polyploidy, habitat differentiation, and sexual selection)	28
8594974622	polyploidy	extra sets of chromosomes due to accidents during cell division	29
8594974623	punctuated equilibrium	the theory that in the evolution there are long periods of little morphological change punctuated by relatively short periods of significant change	30
8594974625	adaptive radiation	Period of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill vacant ecological roles in their communities	31
8594974627	phylogeny	the evolutionary history of a species or group of species	32
8594974629	phylogenetic tree	evolutionary history of a group of organisms represented in a branching diagram	33
8594974630	analogy	similarity due to convergent evolution	34
8594974631	homology	similarity due to shared ancestry	35
8594974632	clade	a group of species which includes an ancestral species and all of its descendants	36
8594974637	Monophyletic	A branch on a phylogenetic tree that contains all decscendants of a common ancestor	37
8594974642	extinction	total disappearance of all members of a species	38
8594974645	fitness	ability to produce surviving offspring	39
8594974646	morphological species concept	new species differ by physical characteristics known as diagnostic traits	40
8594974647	evolutionary species concept	members of a species share distinct evolutionary pathway and common traits	41
8594974648	phylogenetic species concept	a family tree is used to identify species based on a common ancestor	42
8594974649	biological species concept	species are identified as separate because of reproductive isolation.	43