Evolution Terms
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| 7333482559 | evolutionary adaptation | An accumulation of inherited characteristics that enhance organisms' ability to survive and reproduce in specific environments. |  | 0 |
| 7333482560 | artificial selection | The process by which humans selectively breed organisms with desired traits and speed up divergent evolution. |  | 1 |
| 7333482561 | descent with modification | The notion that a species makes discrete changes in the collection of traits over time, which accumulates in speciation. |  | 2 |
| 7333482563 | fitness | The contribution that an individual makes to the gene pool of the subsequent generation. A reflection of how well an organism survives and reproduces in a given environment due to its specific collection of genetic traits. |  | 3 |
| 7333482564 | homology | Similarity resulting from common ancestry. |  | 4 |
| 7333482572 | population genetics | Study of allele frequency distribution and change under the influence of evolutionary processes. | 5 | |
| 7333482575 | Hardy-Weinberg Theorem | The notion that a large, randomly mating population that is experiencing no mutation, gene flow, or selection is not evolving. Frequencies of alleles and genotypes remain constant from generation to generation. |  | 6 |
| 7333482577 | sexual recombination | Crossing over and shuffling of genes during meiosis. |  | 7 |
| 7333482580 | founder effect | When a small number of individuals colonize a new area; the new gene pool is not reflective of original population. |  | 8 |
| 7333482583 | discrete characteristic | Characteristic classified on an either-or basis, determined by a single gene locus. |  | 9 |
| 7333482584 | quantitative characteristic | Characteristic that varies along a continuum, usually due to influence of two or more genes. |  | 10 |
| 7333482585 | geographic variation | Observable differences in the gene pools of separate populations or in discrete subpopulations. |  | 11 |
| 7333482586 | cline | The gradual change in phenotype frequencies over a geographical range that mirrors the gradual change in environmental influences. |  | 12 |
| 7333482587 | relative fitness | Fitness of a particular genotype. |  | 13 |
| 7333482588 | directional selection | Natural selection that favors individuals in a population with more extreme versions of a phenotype. |  | 14 |
| 7333482589 | disruptive selection | Natural selection that favors individuals with either one extreme of a phenotype or the other; the intermediate phenotype is selected against. |  | 15 |
| 7333482590 | stabilizing selection | Natural selection that favors the intermediate phenotype and selects against the extreme phenotypes. |  | 16 |
| 7333482591 | heterozygote advantage | Observed when natural selection favors the heterozygote condition (through greater reproductive success) over either homozygote condition. Maintains variation in a gene pool. ex: Sickle Cell Anemia |  | 17 |
| 7333482592 | sexual selection | The type of natural selection that directly or indirectly favors reproductively advantageous traits. Intrasexual selection refers to direct competition between members of the same sex for access to members of the opposite sex for mating purposes. Intersexual selection refers to the effects of females choosing select males for mating based on their possession of certain desired traits. |  | 18 |
| 7333482593 | sexual dimorphism | The characteristic observed among many species where males and females possess noticeably different physical characteristics. The male can be more phenotypically ornate than the female due to intersexual selection The typical body size of a male and a female can be very different |  | 19 |
| 7333482595 | biological species concept | The definition of a species based on the ability of groups of populations of like organisms to reproduce viable offspring and the inability to do the same with members from other populations. |  | 20 |
| 7333482596 | reproductive isolation | A condition prohibiting members of one species from reproducing with members of another species. Acts to maintain the genetic integrity of a species. |  | 21 |
| 7333482597 | prezygotic isolation | Prevents a hybrid zygote from ever forming between members of different species and preserves the integrity of each species. |  | 22 |
| 7333482598 | habitat isolation | two species do not interbreed because they encounter each other only rarely. |  | 23 |
| 7333482599 | temporal isolation | two species do not interbreed because they breed at different times of day, season, or years. |  | 24 |
| 7333482600 | behavioral isolation | two species do not interbreed because they have incompatible courtship rituals, pheromones, or bird songs. |  | 25 |
| 7333482601 | mechanical isolation | two species do not interbreed because morphological differences prevent fertilization. |  | 26 |
| 7333482602 | gametic isolation | two species do not interbreed because sperm can't fertilize the eggs. |  | 27 |
| 7333482603 | postzygotic barriers | Barriers that prevent the hybrid zygote from becoming a fertile adult. |  | 28 |
| 7333482604 | reduced hybrid viability | hybrid offspring are weak and often don't survive to maturity |  | 29 |
| 7333482605 | reduced hybrid fertility | production of viable but sterile hybrid offspring |  | 30 |
| 7333482606 | hybrid breakdown | Hybrid is fertile, but when they breed the next generation is sterile. |  | 31 |
| 7333482607 | allopatric speciation | speciation that occurs because members of the same ancestral population have become isolated and exposed to different environmental conditions over time. |  | 32 |
| 7333482608 | sympatric speciation | Speciation that occurs in spite of a lack of a geographically isolating mechanism. Common among plants due to polyploidy. |  | 33 |
| 7333482609 | polyploidy | A chromosomal change in which an organism possesses more than two sets of chromosomes. |  | 34 |
| 7333482610 | autopolyploidy | An individual from one species produces polyploid gametes and self-fertilizes. |  | 35 |
| 7333482611 | allopolyploidy | Two different species interbreed and combine their chromosomes. |  | 36 |
| 7333482612 | adaptive radiation | Evolution of many new species from a common ancestor as a result of introduction to new environments. |  | 37 |
| 7333482620 | systematics | The study of the biodiversity and relatedness among organisms, both extinct and extant. |  | 38 |
| 7333482621 | analogy | Anatomical similarity due to convergent evolution; creates analogous structures |  | 39 |
| 7333482622 | homoplasy | When a trait has been gained or lost independently in separate lineages during evolution; convergent evolution |  | 40 |
| 7333482628 | clade | A taxonomic grouping that includes only a single ancestor and all of its descendants. |  | 41 |
| 7333482629 | cladistics | A phylogenetic classification system that uses shared derived characters and ancestry as the sole criterion for grouping taxa. |  | 42 |
| 7333482630 | monophyletic group | A taxonomic grouping that includes an ancestral species and all of its descendants. |  | 43 |
| 7333482631 | paraphyletic group | Groups of species that include the common ancestor and some, but not all, of the descendant species. |  | 44 |
| 7333482632 | polyphyletic group | Groups of species that include members of different ancestral lineages. All members in the grouping do not share a recent common ancestor. |  | 45 |
| 7333482633 | shared primitive character | Trait shared beyond the taxon. |  | 46 |
| 7333482634 | shared derived character | Evolutionary novelty unique to that clade. |  | 47 |
| 7333482635 | outgroup | The taxon or group representing the point of comparison in a cladistic study. Possesses the most distant evolutionary relationship relative to any of the ingroups. |  | 48 |
| 7333482636 | phylograms | A phylogenetic tree in which the lengths of the trunks and branches are relative to the number of genetic differences separating different species. |  | 49 |
| 7333482638 | maximum parsimony | A principle that states that when considering multiple explanations for an observation, the simplest explanation is usually correct Useful when establishing evolutionary relationships between species and in explaining evolutionary adaptations. |  | 50 |
| 7333482639 | maximum likelihood | when considering multiple phylogenetic hypotheses, the one that reflects the most likely sequence of evolutionary events, given certain rules about how DNA changes over time is likely correct |  | 51 |
| 7333482643 | Miller-Urey Experiment | Experiment that found that organic molecules can form in a strongly reducing atmosphere. |  | 52 |
| 7333482644 | protobionts | Aggregates of abiotically produced molecules surrounded by a membrane. |  | 53 |
| 7333482645 | liposomes | Membrane-bound droplets that form when lipids are added to water. |  | 54 |
| 7333482646 | radiometric dating | Dating using decay of radioactive isotopes. |  | 55 |
| 7333482647 | radioisotopes | Isotopes that have unstable nuclei and undergo radioactive decay. |  | 56 |
| 7333482648 | stromatolites | Oldest known fossils formed from many layers of bacteria and sediment. |  | 57 |
| 7333482649 | endosymbiotic theory | Ancestors of mitochondria and plastids were prokaryotes that came to live in a host cell. |  | 58 |
| 7333482650 | colony | Collection of autonomously replicating cells. |  | 59 |
| 7333482673 | antibiotic resistance | Resistance evolving rapidly in many species of prokaryotes due to overuse of antibiotics, especially in agriculture. |  | 60 |
| 10264281979 | analogous structures | Similar structures in different species that may appear similar externally and serve similar functions but develop from different embryonic origins; evidence of convergent evolution. Suggest similar environmental pressures resulting in similar adaptations among species in separate lineages. Examples include the wings of a bat, an insect, and a bird. |  | 61 |
| 10264334308 | postzygotic isolation | Reproductive isolating mechanism that prevents a hybrid zygote from ever developing fully and/or successfully reproducing | 62 | |
| 10264376405 | frequency-dependent selection | A decrease in the reproductive success of an organism of a given phenotype due to the increased frequency of that physical characteristic in the population. |  | 63 |
| 10264432312 | phylogeny | evolutionary history of a species or of a group of closely related species. |  | 64 |
| 10264484497 | ingroup | The group of taxa being studied cladistically that share some derived traits. Helps establish evolutionary relatedness between species. |  | 65 |
| 10264519542 | molecular clock | A mechanism of determining evolutionary time, based on the notion that some parts of the genome change at relatively constant and predictable rates. |  | 66 |
| 10264526223 | fossil record | The extensive collection of data that displays much of the history of life on Earth through the remnants of organisms in sedimentary rock. |  | 67 |
| 10264560567 | endemic | Describes a species that is only found in one discrete geographical location. | 68 | |
| 10264569359 | morphological species concept | The definition of a species based upon shared physical characteristics. Used more exclusively for asexual organisms and before genetic information was known about different species. |  | 69 |
| 10264580528 | balancing selection | Natural selection that maintains relatively stable frequencies of at least two phenotypic traits in a population (balancing polymorphism) | 70 | |
| 10264595553 | heterochrony | Evolutionary change that affects the specific timing and/or rate of an organism's development. |  | 71 |
| 10264598921 | convergent evolution | A pattern of evolution observed when groups of relatively unrelated organisms possess similar traits or morphs due to evolution in similar environments. Not evidence of common ancestry, but instead suggestive of a like response to similar environmental pressures. |  | 72 |
