Evidence for Evolution

• The lesson covers the evidence for evolution

Objectives

• Explain the occurrence of evolution
• Explain how fossil records, comparative anatomy, and genetic information provide evidence for evolution

Evolution

• Evolution refers to a change in organisms over time
• The earliest creatures are no longer around because as the environment changes, living organisms change to adapt

Theories of Evolution

Charles Robert Darwin

• Charles Robert Darwin (1809-1882) was an English naturalist and geologist
• Darwin developed the "Theory of Natural Selection"
• Natural Selection posits the survival of the fittest
• With natural selection the offspring are born with their parents' helpful traits
• Adaptive characteristics prevail in more of the species, but individuals that cannot adapt die off

Jean-Baptiste de Lamarck

• Jean-Baptiste de Lamarck (1744-1829) was the first evolutionist who believed organisms change over time
• Lamarck developed three theories
• Theory of Need- organisms change in response to their environment
• Theory of Use and Disuse - If a body structure is used often, it will develop further, but organs not in use will disappear
• Theory of Acquired Characteristics - Animal characteristics acquired during its lifetime to adapt to the environment can be passed to its offspring

Evidences of Evolution

• Fossil Evidences
  • Fossil evidence provides a preserved physical remain of organisms that provides a narrative of organisms' evolution over millions of years
  • Types Of Fossilization include carbon dating
• Comparative Anatomy
  • Comparative anatomy studies similarities and differences in the structure of organisms

Homologous vs. Analogous Structure

• Homologous Structure
  • Leads to divergent evolution where species perform different functions in the environment or may have the same origin but different roles in the the environment

Analogous Structure

• Leads to convergent evolution and has similar functions with different origins

  • Structures of unrelated species may evolve to look alike because they adapt to similar functions

    Compression and impression

  • Compression involves the flattening and preservation of organic material under pressure, creating a two-dimensional representation of the organism.

  • impression fossils are formed when an organism leaves a distinct mark in sediment, capturing its shape without any preservation of the actual organic material. Both methods provide valuable insights into past life and geological conditions.