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The science of evolution Ammonite fossil photo credit Dave Strauss, Nautilus courtesy of Helina Chin. At the heart of evolutionary theory are the basic ideas that life has changed over time and that different species share common ancestors. Overwhelming evidence supports these facts.
Darwinism. Charles Darwin in 1868. Darwinism is a theory of biological evolution developed by the English naturalist Charles Darwin (1809–1882) and others, stating that all species of organisms arise and develop through the natural selection of small, inherited variations that increase the individual's ability to compete, survive, and reproduce.
In biology, evolution is the process of change in all forms of life over generations, and evolutionary biology is the study of how evolution occurs. Biological populations evolve through genetic changes that correspond to changes in the organisms ' observable traits. Genetic changes include mutations, which are caused by damage or replication ...
Darwin and Wallace develop similar theory. Wallace in 1902. Image courtesy of the Alfred Russel Wallace Page. Darwin began formulating his theory of natural selection in the late 1830s but he went on working quietly on it for twenty years. He wanted to amass a wealth of evidence before publicly presenting his idea.
Although the theory of evolution generated some controversy when Darwin first proposed it, biologists almost universally accepted it, particularly younger biologists, within 20 years after publication of On the Origin of Species. Nevertheless, the theory of evolution is a difficult concept and misconceptions about how it works abound.
Evo 101. Natural Selection. Natural selection is one of the basic mechanisms of evolution, along with mutation, migration, and genetic drift. Darwin’s grand idea of evolution by natural selection is relatively simple but often misunderstood. To see how it works, imagine a population of beetles: There is variation in traits.
Evolution 101. An introduction to evolution: what is evolution and how does it work? The history of life: looking at the patterns – Change over time and shared ancestors; Mechanisms: the processes of evolution – Selection, mutation, migration, and more; Microevolution – Evolution within a population; Speciation – How new species arise
