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Chapter Summary

  1. Charles Darwin’s theory of evolution by natural selection produced a paradigm shift in the life sciences.
  2. In On the Origin of Species, Darwin presented two revolutionary ideas: (a) the wide diversity of life we see around us has descended from previously existing species, which share common ancestry, and (b) the present forms of these species are a result primarily of natural selection, a process in which forms that are better suited to their environment increase in frequency over time.
  3. Evolutionary biologists infer the causes of ancient events, and develop and test hypotheses through a combination of observation and experimental manipulations.
  4. Artificial selection by humans is the counterpart to natural selection. Humans select which individuals get to reproduce by choosing those that possess traits that are beneficial to us, which changes the phenotype of domesticated varieties over time.
  5. Practical applications of understanding evolution via natural selection include, but are not limited to, controlling resistance to insecticides and antibiotics, as well as using evolutionary principles to address problems in conservation biology and the medical sciences.
  6. All species that have ever lived form a vast branching tree of evolutionary relationships known as the tree of life.
  7. Theory plays an important role in shaping and furthering the research agenda in evolutionary biology. Models can be employed both to make predictions and to use observable patterns to infer information that is more difficult to observe directly.