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| 7593860412 | speciation | an evolutionary process in which one species splits into two or more species | 0 | |
| 7593860413 | biological species concept | definition of a species as a population or 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 such groups | 1 | |
| 7593860414 | microevolution | evolutionary change below the species level; change in the allele frequencies in a population over generations | 2 | |
| 7593860415 | micraevolution | evolutionary change above the species level, including the origin of new group of organisms or a shift in the broad pattern of evolutionary change over a long period of time | 3 | |
| 7593860416 | gene flow | the transfer of alleles from one population to another, resulting from the movement of fertile individuals to their gametes | 4 | |
| 7593860417 | phenotype | the physical and physiological traits of an organism, which are determined by its genetic makeup | 5 | |
| 7593860418 | species | a population or 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 | 6 | |
| 7593860419 | reproductive isolation | the existence of biological factors that impede members of two species from producing viable, fertile offspring | 7 | |
| 7593860420 | polyploid | a species that originates from an accident during cell division | 8 | |
| 7593860421 | autoployploid | an individual that has more than two chromosome sets that are all derived from a single species | 9 | |
| 7593860422 | allopolyploid | a changed sterile hybrid through various mechanisms through generations into a fertile polypoid | 10 | |
| 7593860423 | habitat differentiation | the sympatric speciation caused by an environmental barrier | 11 | |
| 7593860424 | sexual selection | natural selection arising through preference by one sex for certain characteristics in individuals of the other sex | 12 | |
| 7593860425 | hybrids | offspring that results from two different species or two true-breeding varieties of the same species | 13 | |
| 7593860426 | prezygotic barriers | a reproductive barrier that impedes mating between species or hinders fertilization if interspecific mating is attempted | 14 | |
| 7593860427 | habitat isolation | two species that occupy different habits within the same area may encounter each other rarely, if at all, even through they are not isolated by obvious physical barriers, such as mountain ranges | 15 | |
| 7593860428 | temporal isolation | species that breed during different times of the day, different seasons, or different years cannot mix their gametes | 16 | |
| 7593860429 | behavior isolation | courtship rituals that attract mates and other behaviors unique to a species are effective reproductive barriers, even between closely related species. Such behavioral rituals enable mate recognition - a way to identify potential mates of the same species | 17 | |
| 7593860430 | mechanical isolation | mating is attempted, but morphological differences prevent its successful completion | 18 | |
| 7593860431 | gametic isolation | sperm of one species may not be able to fertilize the eggs of another species. For instance, sperm may not be able to survive in the reproductive tract of females of other species, or biochemical mechanisms may prevent the sperm from penetrating the membrane surrounding the other species' eggs | 19 | |
| 7593860432 | postzygotic barriers | a reproductive barrier that prevents hybrid zygotes produced by two different species from developing into viable, fertile adults | 20 | |
| 7593860433 | reduced hybrid viability | the genes of different parent species may interact in ways that impair the hybrid's development or survival in its environment | 21 | |
| 7593860434 | reduced hybrid fertility | even if hybrids are vigorous, they may be sterile. if the chromosomes of the two parent species differ in number or structure, meiosis in the hybrids may fail to produce normal gametes. since the infertile hybrids cannot produce offspring when they mate with either parent species, genes cannot flow freely between the species | 22 | |
| 7593860435 | hybrid breakdown | some first generation hybrids are viable and fertile, but when they mate with one another or with either parent species, offspring of the next generation are feeble and sterile. | 23 | |
| 7593860436 | morphological species concept | a definition of species in terms of measurable anatomical criteria | 24 | |
| 7593860437 | ecological species concept | a definition of species composition of a community following a disturbance; the establishment of a community in an area virtually barren of life | 25 | |
| 7593860438 | phylogenetic species concept | a definition of species as the smallest group of individuals that share a common ancestor, forming one branch on the tree of life | 26 | |
| 7593860439 | allopatric speciation | the formation of new species in populations that are geographically isolated from one another | 27 | |
| 7593860440 | sympatric speciation | the formation of new species in populations that live in the same geographic area | 28 | |
| 7593860441 | hybrid zone | a geographic region in which members of different species meet and mate, producing at least some offspring of mixed ancestry | 29 | |
| 7593860442 | punctuated equilibrium | in the fossil record, long periods of apparent stasis, in which a species undergoes little or no morphological change, interrupted by relatively brief periods of sudden change | 30 | |
| 7593860443 | graduated equilibrium | in the fossil record, long periods of apparent stasis, in which a species undergoes little or no morphological change, interrupted by relatively long periods of sudden change | 31 |
