True-False Section 1. Evolution necessitates long-term progress in any set direction. An increased variation of organisms within a species decreases the possibility that some members of the species will survive changed environmental conditions. Many organism behaviors have evolved through natural selection. Meiosis and fertilization make possible a great variety of gene combinations which drive natural selection.
Evolutionary changes appear to be like the growth of a bush.
Some branches survive from the beginning with little or no change, many die out all together, and others branch repeatedly, sometimes giving rise to more complex organisms. The great diversity of organisms is thought by evolutionists to be the result of billions of years of evolution that has filled the earth's niches with available life forms. Extinction of species is relatively uncommon. Most of the species that have lived on the earth are currently alive. The closer the DNA sequences between two different organisms, the lesser the kinship or evolutionary relationship between them.