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genetic change in a population as a result of natural selection, avg state of a characteristic improves with reference to specific function or to some feature of its environment; a feature that has become prevalent within the population because of its advantage in some function; very complex

creationist movement

opposes the teaching of evolution in public schools, or at least demands "equal time" for their beliefs; arising from fear that evolutionary science denies the existence of God, therefore denying any basis for rules of moral or ethical conduct.

descent with modification

all species, living and extinct, have descended, without interruption, from one or a few orignial forms of life; common ancestor.


philosophical view that all members of a class of objects (such as a species) share certain invariant, unchanging properties that distinguish them from other classes.

evolution (biological evolution; organic evolution)

origin of entities processing different states of one or more charcteristics and changes in the proportions of those entities over time. change over time in the proportions of individual organisms differing genetically one or more traits; changes occur from alteration of the frequencies of genotypes from generation to generation within populations, by alteration of the proportions of genetically differentiated populations within a species, or by changes in the numbers of species with different characteristics, thereby altering the frequency of one or more traits within a higher taxon.

evolutionary synthesis (=modern syntehsis) hypothesis

the reconciliation of Darwin's theory with the findings of modern genetics, which gave rise to a theory that emphasized the coaction of random mutation, selection, genetic drift, and gene flow

inheritance of acquired characteristics

alterations acquired during an individual's lifetime are inherited; Lamarck (famous example is giraffes once had short necks but they stretched their necks to reach foliage above them)


vague term, the evolution of substantial phenotypic changes, usually great enough to place the changed lineage and its descendants in a distinct genus or higher taxon.


vague term, usually referring to slight, short-term evolutionary changes within species.

natural selection

differential survival and/or reproduction of classes of entities that differ in one or more characteristics; the difference in survival and/or reproduction cannot be due to chance as well as having consequences of altering the proportions of different entities; usually differences are inherited; entities may be alleles genotypes or subsets of genotypes, populations, or in the broadest sense, species; complex concept


a of conspecific (belonging to the same species) organisms that occupy a more or less well defined geographic region and exhibit reproductive continuity from generation to generation; ecological and reproductive interactions are more frequent among these individuals than with members of other populations of the same species.

scientific theory

a mature coherent body of interconnected statements based on reasoning and evidence that explain some aspect of nature--usually many


James Hutton and Charles Lyell expounded this principle holding that the same processes operated in the past as in the present, and that the observations of geology should therefore be explained by causes that we can now observe; Darwin involved this type of thinking


each species (or higher taxon) was created seperately; essentially in its present form, buy a supernatural Creator.

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