Evidence for evolution

• Evidence for evolution

  • Palaentology
  • Comparative anatomy
  • Comparative biochemistry
• Palaentology= study of fossils and the fossil record
• Comparative anatomy= study of similarly and differences between organisms anatomy.
• Comparative biochemistry= similarities and differences between the chemical makeup of organisms
• Palaentology

  Fossils are formed when animal and plant remains are preserved in rocks.

  Over long periods of time sediment is deposited to form layers.

  Different layers correspond to different geological eras.

  Shows how organisms have changed over time.
• Evidence provided by fossil record

  • Fossils of simplest organisms are found in earliest rocks, more complex organisms are found in recent rocks. So support evolutionary theory that simple life form gradually evolved to more complex ones.
  • Sequence in which organisms are found matches their evolutionary links to each other.
  • Study similarities in the anatomy of fossil organisms, to show how closely related organisms have evolved from common ancestors.
  • Allow relationships between extinct and living organisms.
• Fossil record not complete

  = Many organisms are soft bodied so decompose quickly before they have a change to fossilised.

  Other fossils may have been destroyed by earth movements.
• Homologous structures= structure that appears superficially different in different organisms ut has the same underlying structure.

  • Provides evidence for divergent evolution.
• Divergent evolution= when closely related species diversify to adapt to new habitats as a result of migration or loss of habitat.