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Natural Selection &


evolution a gradual change in the characteristics of a population of animals or plants over successive generations
natural selection the process whereby organisms better adapted to their environment tend to survive and produce more offspring. The theory of its action was first fully expounded by Charles Darwin and is now believed to be the main process that brings about evolution.
Charles Darwin English naturalist, geologist and biologist, best known for his contributions to the science of evolution. His proposition that all species of life have descended over time from common ancestors
fitness Fitness is the quantitative representation of natural and sexual selection within evolutionary biology. It can be defined either with respect to a genotype or to a phenotype in a given environment.
variability lack of consistency or fixed pattern; liability to vary or change.
inheritability capable of being transmitted by heredity from one generation to a later one. capable of being inherited. rare capable of inheriting; having the right to inherit.
artificial selection The breeding of plants and animals to produce desirable traits. Organisms with the desired traits, such as size or taste, are artificially mated or cross-pollinated with organisms with similar desired traits.
adaptation alteration in the structure or function of an organism or any of its parts that results from natural selection and by which the organism becomes better fitted to survive and multiply in its environment.
structural adaptation physical features of an organism like the bill on a bird or the fur on a bear
mimicry evolved resemblance between an organism and another object, often an organism of another species.
camouflage the disguising of military personnel, equipment, and installations by painting or covering them to make them blend in with their surroundings.
fossil record total number of fossils that have been discovered, as well as to the information derived from them.
homologous structure existence of shared ancestry between a pair of structures, or genes, in different taxa.
analogous structure similarity of function and superficial resemblance of structures that have different origins.
vestigial structure/organ anatomical feature or behavior that no longer seems to have a purpose in the current form of an organism of the given species
embryology the branch of biology and medicine concerned with the study of embryos and their development.
gene pool the stock of different genes in an interbreeding population.
genetic drift variation in the relative frequency of different genotypes in a small population, owing to the chance disappearance of particular genes as individuals die or do not reproduce.
allele/gene frequency relative frequency of an allele (variant of a gene) at a particular locus in a population, expressed as a fraction or percentage.
stabilizing selection type of natural selection in which the population mean stabilizes on a particular non-extreme trait value
bottleneck effect sharp reduction in the size of a population due to environmental events or human activities.
founder effect the reduced genetic diversity which results when a population is descended from a small number of colonizing ancestors.
fossil the remains or impression of a prehistoric organism preserved in petrified form or as a mold or cast in rock.
speciation the formation of new and distinct species in the course of evolution.
directional selection mode of natural selection in which an extreme phenotype is favored over other phenotypes, causing the allele frequency to shift over time in the direction of that phenotype.
Created by: mercedes baker