Evidence for Evolution

Rucete ✏ Biology In a Nutshell

1. Fossil Record

  • Shows a chronological sequence of life on Earth.
  • Documents the existence of species that are now extinct.
  • Reveals transitional forms, linking ancestral and modern species (e.g., Archaeopteryx).

2. Biogeography

  • Study of the geographic distribution of species.
  • Related species often found in close geographic proximity, even if habitats differ.
  • Isolated areas like islands often have unique species that evolved from common ancestors (e.g., Galápagos finches).

3. Embryology

  • Embryos of different species show similar developmental stages.
  • Suggests common ancestry, especially when early embryos share features (e.g., pharyngeal pouches in fish and humans).

4. Comparative Anatomy

a) Homologous Structures

  • Body parts with different functions but similar structures, indicating common ancestry.
  • Example: forelimbs of cats, bats, whales, and humans.

b) Analogous Structures

  • Body parts with similar functions but different structures, suggesting convergent evolution.
  • Example: fins and body shapes of sharks, penguins, and porpoises.

5. Molecular Biology

  • DNA and protein comparisons reveal similarities among species.
  • Organisms with more similar nucleotide or amino acid sequences are more closely related.
  • Supports the idea of shared evolutionary history at the molecular level.

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