Chapter 21, "Darwinism and the Evidence for Evolution," introduced you to the fundamental evidence for evolution and the mechanisms by which evolution occurs. These hyperlinks will expand your knowledge of natural selection and introduce you to current research and debates by today's scientists.
21.1 The Evidence for Evolution
Life on Earth: Stephen Jay Gould
Stephen Jay Gould is one of the most prominentand prolificevolutionary biologists of our time. At this site, sponsored by Scientific American, he discusses the theory of natural selection, as well as the types of evidence that support this theory.
Keywords: fossil record, variation, evolutionary pressure
Theories in Evolution
In this article from American Scientist, the evolution of structural components is examined using a famous analogyconstruction of the spandrels of Saint Mark's Cathedral. This site provides a good introduction to different ways of thinking about evolution and shows how biologists' thinking is often influenced by ideas outside of traditional experimental science.
Keywords: adaptation, fitness, natural selection
History of Evolution
This timeline for evolutionary thought introduces you to some lesser-known evolutionary theorists. Follow the links to learn about the big names in the development of evolutionary thought and to see how the development of a theory often has a rich history of changing ideas.
Keywords: Lamarck, Linnaeus, Agassiz
21.2 How Natural Selection Works
The Evo-Tutor site allows you to change the parameters of a virtual population and simulate the effects of these changes on the evolution of that population. The site also explains mathematical models that describe changes in gene frequency.
Keywords: Hardy-Weinberg equilibrium, variation, population genetics
This site, from the Gulf of Maine Aquarium, provides a case study of adaptation, focusing on how and why penguins are so well suited for their environment. Unique environmental pressures exist in the typical penguin habitat, and this model is instructive in learning about how these evolutionary pressures may shape the populations' characteristics.
Keywords: adaptation, natural selection, evolutionary study
Darwin's Finches and Speciation
21.3 Evolution in Action: Recent Research in Natural Selection
This article on the evolution of the Galapagos finches describes how the evolution of beak size may have driven changes in the mating behaviors of the Galapagos finches. The concepts outlined in the article imply a fascinating interplay between natural and sexual selection.
Keywords: natural selection, adaptation, speciation
The random and incomplete nature of the fossil record is one of the main stumbling blocks to accepting the evidence for the theory of evolution by natural selection. This page, from Indiana University's Evolution and the Nature of Science Institutes, presents a series of deductions on evolutionary theory. Test your understanding of evolution by responding to each of these deductions.
Keywords: deductive reasoning, evolution, scientific evidence