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| 4872945917 | homologous structures | structures in different species that are similar because of common ancestry |  | 0 |
| 4872945918 | vestigial structures | remnants of features that served important functions in the the organism's ancestors |  | 1 |
| 4872945919 | convergent evolution | the independent evolution of similar features in different lineages |  | 2 |
| 4872945920 | 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 |
| 4872945921 | gene pool | the aggregate of all of the alleles for all of the loci in individuals in a population |  | 4 |
| 4872945922 | population | a group of individuals of the same species that live in the same area and interbreed, producing fertile offspring |  | 5 |
| 4872945923 | 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 |
| 4872945924 | genetic drift | changes in the gene pool due to random events | 7 | |
| 4872945925 | 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 |
| 4872945926 | 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 |
| 4872945927 | gene flow | the transfer of alleles into or out of a population due to the movement of fertile individuals or their gametes | 10 | |
| 4872945928 | 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 |
| 4872945929 | disruptive selection | when conditions favor individuals at both extremes of a phenotypic range over individuals with intermediate phenotypes |  | 12 |
| 4872945930 | stabilizing selection | acts against both extreme phenotypes and favors intermediate variants |  | 13 |
| 4872945931 | sexual selection | a form of natural selection in which individuals with certain inherited characteristics are more likely than other individuals to obtain mates |  | 14 |
| 4872945932 | 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 |
| 4872945933 | diploidy | the state of being diploid, that is having two sets of chromosomes | 16 | |
| 4872945934 | heterozygote advantage | when individuals who are heterozygous at a particular locus have greater fitness than do both kind of homozygous | 17 | |
| 4872945935 | frequency-dependent selection | fitness of a phenotype declines if it becomes too common in the population | 18 | |
| 4872945936 | speciation | the process by which one species splits into two or more species |  | 19 |
| 4872945937 | microevolution | changes over time in allele frequencies in a population | 20 | |
| 4872945938 | macroevolution | the broad pattern of evolution over long time spans | 21 | |
| 4872945939 | 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 | |
| 4872945940 | reproductive isolation | the existance of biological barriers that impede members of two species from producing viable offspring | 23 | |
| 4872945941 | hybrids | offspring that result from interspecific mating |  | 24 |
| 4872945942 | prezygotic barriers | impede mating or hinder fertilization if mating occurs (five types: habitat, temporal, behavioral, mechanical, gametic) |  | 25 |
| 4872945943 | post zygotic barriers | prevents hybrid zygote from developing into a viable fertile adult through reducing hybrid viability, reducing hybrid fertility, or hybrid breakdown | 26 | |
| 4872945944 | allopatric speciation | gene flow is interrupted when a population is divided into geographically isolated subpopulations |  | 27 |
| 4872945945 | sympatric speciation | speciation occurs in populations that live in the same geographic area (usually occurs due to polyploidy, habitat differentiation, and sexual selection) |  | 28 |
| 4872945946 | polyploidy | extra sets of chromosomes due to accidents during cell division |  | 29 |
| 4872945947 | autopolyploid | an individual that has more than two chromosome sets that are all derived from a single species |  | 30 |
| 4872945948 | allopolyploid | an individual that has more than two chromosome sets due to two different species interbreeding and after several generations can change a sterile hybrid into a fertile polyploid. Allopolyploids are fertile when mating with each other but cannot interbreed with either parent species |  | 31 |
| 4872945949 | punctuated equilibrium | the theory that in the evolution there are long periods of little morphological change punctuated by relatively short periods of significant change |  | 32 |
| 4872945950 | ribozyme | RNA that can also carry out a number of enzyme-like catalytic functions | 33 | |
| 4872945951 | protobionts | collections of abiotically produced molecules surrounded by a membrane-like structure with simple chemical reactions (precursor of prokaryotic cells) | 34 | |
| 4872945952 | endosymbiosis | mitochondria and chloroplasts were formally small prokaryotes that began living within larger cells |  | 35 |
| 4872945953 | 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 |  | 36 |
| 4872945954 | 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 | 37 | |
| 4872945955 | phylogeny | the evolutionary history of a species or group of species |  | 38 |
| 4872945956 | systematics | study and classification of biodiversity and determining their evolutionary relationships | 39 | |
| 4872945957 | phylogenetic tree | evolutionary history of a group of organisms represented in a branching diagram |  | 40 |
| 4872945958 | analogy | similarity due to convergent evolution |  | 41 |
| 4872945959 | homology | similarity due to shared ancestry |  | 42 |
| 4872945960 | clade | a group of species which includes an ancestral species and all of its descendants | 43 | |
| 4872945961 | 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 | 44 | |
| 4872945962 | maximum parsimony | 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 |  | 45 |
| 4872945963 | molecular clock | a yardstick for measuring the absolute time of evolutionary change based on the observation that some genes and other regions of genomes appear to evolve at constant rates | 46 | |
| 4872945964 | horizontal gene transfer | a process in which genes are transferred from one genome to another through mechanisms such as exchange of transposable elements and plasmids, viral infection and perhaps fusion of organisms |  | 47 |
| 4872945965 | Darwin's Theory (five parts) | 1. Variation 2. Overproduction 3. Competition 4. Survival of the fittest 5. Overtime, emergence of new species (new alleles) | 48 |
