| Question | Answer |
| Adaptive radiation | the diversification of a common ancestral species into a variety of differently adapted species |
| Fossil record | the remains and traces of past life that are found in sedimentary rock; it reveals the history of life on Earth and the kinds of organisms that were alive in the past |
| Adaptation | a structure, behaviour, or physiological process that helps an organism survive and reproduce in a particular environment |
| Gradualism | a model of evolution that views evolutionary change as slow and steady, before and after a divergence |
| Ecological niche | the ecological role and physical distribution of a species in its environment |
| Inheritance of acquired characteristics | the idea that characteristics acquired during an organism’s lifetime can be passed on to its offspring |
| Punctuated equilibrium | a model of evolution that views evolutionary history as long periods of stasis, or equilibrium, that are interrupted by periods of divergence |
| Gene Flow | the net movement of alleles from one population to another due to the migration of individuals |
| Allopatric speciation | speciation in which a population is split into two or more isolated groups by a geographical barrier; also called geographical speciation |
| Vestigial structure | a structure that is a reduced version of a structure that was functional in the organism’s ancestors |
| Fitness | the ability of an organism to produce viable offspring capable of surviving to the next generation |
| Mutation | a permanent change in the genetic material of an organism; the only source of new genetic variation |
| Survival of the fittest | the idea that the organisms that are the fittest leave the most offspring, so those organisms win the struggle for survival; phrase coined by John Spencer |
| Paleontology | the study of ancient life through the examination of fossils |
| Founder effect | a change in a gene pool that occurs when a few individuals start a new isolated population |
| Selective advantage | a genetic advantage that improves an organism’s chance of survival, usually in a changing environment |
| Homologous structure | structures that have similar structural elements and origin but may have a different function |
| Mimicry | a structural adaptation in which a harmless species resembles a harmful species in coloration or structure |
| Stabilizing selection | natural selection that favours intermediate phenotypes and acts against extreme variants |
| Uniformitarianism | Charles Lyell’s theory (based on Hutton’s theory) that geological processes operated at the same rates in the past as they do today |
| Non-random mating | mating among individuals on the basis of mate selection for a particular phenotype or due to inbreeding |
| Sympatric speciation | speciation in which populations within the same geographical areas diverge and become reproductively isolated |
| Evolution | the process of genetic change in a population over time |
| Transitional fossil | a fossil that shows intermediary links between groups of organisms and shares characteristics common to two now separate groups |
| Directional selection | natural selection that favours the phenotypes at one extreme over another, resulting in the distribution curve of phenotypes shifting in the direction of that extreme |
| Post-zygotic isolating mechanism | a barrier that prevents hybrid zygotes from developing into viable, fertile individuals; also called post-fertilization barrier |
| Extinct | describes a species that has completely disappeared from Earth |
| Biogeography | the study of the past and present geographical distribution of species populations |
| Natural selection | the process by which characteristics of a population change over many generations as organisms with heritable traits survive and reproduce, passing their traits to offspring |
| Artificial selection | selective pressure exerted by humans on populations in order to improve or modify particular desirable traits |
| Selective pressure | environmental conditions that select for certain characteristics of individuals and select against other characteristics |
| Disruptive (diversifying) selection | natural selection that favours the extremes of a range of phenotypes rather than intermediate phenotypes; this type of selection can result in the elimination of intermediate phenotypes |
| Variation | differences between individuals, which may be structural, functional, or physiological |
| Analogous structure | structures of organisms that do not have a common evolutionary origin but perform similar functions |
| Theory of evolution by natural selection | a theory explaining how life has changed, and continues to change, during Earth’s history |
| Catastrophism | the idea that catastrophes such as floods, diseases, and droughts periodically destroyed species living in a particular region, allowing species from neighbouring regions to repopulate the area |
| Embryology | the study of early, pre-birth stages of an organism’s development |
| Genetic Drift | the change in frequencies of alleles due to chance events in a breeding population |
| Convergent evolution | a pattern of evolution in which similar traits arise because different species have independently adapted to similar environmental conditions |
| Pre-zygotic isolating mechanism | a barrier that either impedes mating between species or prevents fertilization of the eggs if individuals from different species attempt to mate; also called pre-fertilization barrier |
| Theory | in science a theory is a set of principles that explain and predict phenomena. All theories in science are based on an immense amount of observed evidence |
| Speciation | the formation of new species from existing species |
| Sexual selection | natural selection for mating based, in general, on competition between males and choices made by females |
| Descent with modification | Darwin’s theory that natural selection does not demonstrate progress, but merely results from a species’ ability to survive local conditions at a specific time |
| Monoculture | the agricultural practice of planting large expanses of uniform varieties of the same species. |
| Biotechnology | the use of technology and organisms to produce useful products |
| Bottleneck effect | changes in gene distribution that result from a rapid decrease in population size |
| Divergent evolution | a pattern of evolution in which species that were once similar to an ancestral species diverge, or become increasingly distinct |
