The work of Charles Darwin and Alfred Wallace on the origin of the Earth's species extended the ideas of Lyell's uniformitarianism into the biological sciences. The theory of evolution is based on the principle that the diversity seen in the Earth's species can be explained by the A) random variation in the genetics of any population. B) idea that in any population, too many individuals are produced. C) uniform modification of genetic traits over long periods of time. D) sudden change in the gene pool due to mutations within the DNA of a given population.