AP Biology: Evolution Flashcards

9601838881	homologous structures	structures in different species that are similar because of common ancestry	0
9601838882	vestigial structures	remnants of features that served important functions in the the organism's ancestors	1
9601838883	convergent evolution	the independent evolution of similar features in different lineages	2
9601838884	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
9601838885	gene pool	the aggregate of all of the alleles for all of the loci in individuals in a population	4
9601838886	population	a group of individuals of the same species that live in the same area and interbreed, producing fertile offspring	5
9601838887	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
9601838888	genetic drift	changes in the gene pool due to random events	7
9601838889	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
9601838890	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
9601838891	gene flow	the transfer of alleles into or out of a population due to the movement of fertile individuals or their gametes	10
9601838892	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
9601838893	disruptive selection	when conditions favor individuals at both extremes of a phenotypic range over individuals with intermediate phenotypes	12
9601838894	stabilizing selection	acts against both extreme phenotypes and favors intermediate variants	13
9601838895	sexual selection	a form of natural selection in which individuals with certain inherited characteristics are more likely than other individuals to obtain mates	14
9601838896	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
9601838897	diploidy	the state of being diploid, that is having two sets of chromosomes	16
9601838898	heterozygote advantage	when individuals who are heterozygous at a particular locus have greater fitness than do both kind of homozygous	17
9601838899	frequency-dependent selection	fitness of a phenotype declines if it becomes too common in the population	18
9601838900	speciation	the process by which one species splits into two or more species	19
9601838901	microevolution	changes over time in allele frequencies in a population	20
9601838902	macroevolution	the broad pattern of evolution over long time spans	21
9601838903	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
9601838904	reproductive isolation	the existance of biological barriers that impede members of two species from producing viable offspring	23
9601838905	hybrids	offspring that result from interspecific mating	24
9601838908	allopatric speciation	gene flow is interrupted when a population is divided into geographically isolated subpopulations	25
9601838909	sympatric speciation	speciation occurs in populations that live in the same geographic area (usually occurs due to polyploidy, habitat differentiation, and sexual selection)	26
9601838910	polyploidy	extra sets of chromosomes due to accidents during cell division	27
9601838912	endosymbiosis	mitochondria and chloroplasts were formally small prokaryotes that began living within larger cells	28
9601838913	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	29
9601838914	homeotic genes	master regulatory genes that determine such basic features as where a pair of wings and a pair of legs will develop on a bird or how a plant's flower parts are arranged	30
9601838915	phylogeny	the evolutionary history of a species or group of species	31
9601838917	phylogenetic tree	evolutionary history of a group of organisms represented in a branching diagram	32
9601838918	analogy	similarity due to convergent evolution	33
9601838919	homology	similarity due to shared ancestry	34
9601838920	clade	a group of species which includes an ancestral species and all of its descendants	35
9601838921	outgroup	a species or group of species from an evolutionary lineage that is known to have diverged before the lineage that includes the species we are studying	36
9601838922	maximum parsimony (Ockham's Theory)	a principle that states that when considering multiple explanations for an observation, one should first investigate the simplest explanation that is consistent with the facts	37
9601838923	Darwin's Theory (five parts)	1. Variation 2. Overproduction 3. Competition 4. Survival of the fittest 5. Overtime, emergence of new species (new alleles)	38
9601838925	Monophyletic	A branch on a phylogenetic tree that contains all decscendants of a common ancestor	39
9601838926	Abiogenesis	origin of life from nonliving matter	40
9601838928	ozone shield	protect organisms from harmful UV rays	41
9601838929	geologic timescale	division of the history of Earth into eras, periods and epochs	42
9601838930	extinction	total disappearance of all members of a species	43
9601838931	mass extinction	total disappearance of a large number a species within a few million years	44
9601838932	extant	still in existance	45
9601838934	morphological species concept	new species differ by physical characteristics known as diagnostic traits	46
9601838935	evolutionary species concept	members of a species share distinct evolutionary pathway and common traits	47
9601838936	phylogenetic species concept	a family tree is used to identify species based on a common ancestor	48
9601838937	biological species concept	species are identified as separate because of reproductive isolation.	49
9601838938	plate tectonics	branch of geology which follows the movement of pieces of Earth's crust which float on a lower, hot mantle layer	50
9601838939	continental drift	change over time of the positions of the continents	51
9601838940	fossil	remains and traces of evidence of past life	52
9601838941	paleontology	study of the fossil record	53
9601838942	index fossils	fossils used to identify deposits made at apparently the same time in different parts of the world, used for relative dating	54
9601838943	absolute dating	relies on radiometric dating to assign an age to a fossil	55