Charles Darwin and Evolution

Charles Darwin and the Theory of Evolution

• Charles Darwin proposed that natural mechanisms produce and transform the diversity of life on Earth through evolution.
• His concept of evolution forms the unifying intellectual paradigm within which all biological research is undertaken.

Lamarck's Theory of Evolution

• Jean Baptiste de Lamarck theorized that two mechanisms fostered evolutionary change:
  • The Principle of use and disuse: body parts grow or weaken according to use.
  • The Principle of acquired traits: changes acquired during an organism's lifetime are inherited by its offspring.
• Although Lamarck's mechanisms do not cause evolutionary change, he made four significant contributions to the development of an evolutionary worldview:
  • Species change over time.
  • New characteristics are passed from one generation to the next.
  • Organisms change in response to their environment.
  • Specific mechanisms cause evolutionary change.

Evolutionary Concepts

• Biological evolution occurs in populations when genetic changes cause the genome to differ from ancestors.
• These genetic changes and their phenotypic modifications are the products of evolution.
• Biologists strive to understand the processes that cause evolutionary change by studying the products of evolution.

Alfred R. Wallace and Biogeography

• Alfred R. Wallace contributed to the Theory of Evolution, and his work is closely tied to biogeography, the study of the geographic distribution of organisms.

Assignment Questions

• Kangaroos are found on the continent of Australia naturally due to evolutionary adaptations.
• Elephants are not found in Australia naturally due to geographical and evolutionary factors.

Definitions

• Natural Selection: the process by which organisms that are better adapted to their environment are more likely to survive and reproduce.
• Biogeography: the study of the geographic distribution of organisms.
• Rhea: a type of flightless bird found in South America, scientifically known as Rhea americana.
• Emu: a type of flightless bird found in Australia, scientifically known as Dromaius novaehollandiae.
• Ostrich: a type of flightless bird found in Africa, scientifically known as Struthio camelus.