AAC - 04 - Concept 1 Notes - Evidence of Evolution PPT

Evidence of Evolution

Overview

• Evolution is the "unifying theme of biology."

• Integrates research from various fields:

  • Paleontology: Studies the fossil record of prehistoric life.

  • Morphology: Examines the form and structure of living organisms.

  • Biogeography: Investigates geographic distribution of species.

  • Embryology: Focuses on embryo development.

  • Biochemistry: Analyzes chemical processes in living organisms.

• Evidence also comes from direct observation of changes in populations.

Evidence in Paleontology

• Fossils: Preserved remains of organisms (e.g., bones, footprints, feces).

  • Reveal the history and types of organisms that have existed, including extinct species.

  • Transitional fossils: Link ancestral species to their descendants, essential for understanding evolutionary history.

    • Example: Archaeopteryx is a transitional fossil between birds and dinosaurs.

Evidence in Morphology

• Homologous structures:

  • Similar anatomical structures suggesting common ancestry.

  • Serve different functions due to evolution in diverse environments (divergent evolution).

• Vestigial structures:

  • Body parts with little or no current function.

  • Likely remnants from ancestors who utilized the structures, indicating divergent evolution.

• Analogous structures:

  • Structures with similar functions that evolved independently in unrelated organisms (convergent evolution).

  • Different structures, similar functions due to adaptation to similar environments.

Evidence in Biogeography

• Distribution of species corresponds to theories of continental drift and Pangea.

  • Endemic species: Organisms unique to a specific geographic area.

    • Example: Galapagos tortoises are found only in the Galapagos Islands.

  • Nearby species often resemble each other, indicating potential divergent evolution.

Evidence in Embryology

• Early developmental similarities in vertebrate embryos suggest a common ancestry among vertebrates.

Evidence in Biochemistry

• Analyzing DNA and proteins across species reveals genetic similarities indicative of common ancestry.

  • Related species show closely matched DNA sequences.

  • Pseudogenes: Nonfunctional relics of evolutionary history, akin to vestigial structures in DNA.

    • Example: Genetic similarities between hippopotamus and humpback whale.

Evidence from Direct Observation

• Microevolution: Observable changes within populations, particularly those with short life cycles.

  • Examples:

    • Peppered moths demonstrate changes in coloration in response to environmental factors.

    • Mosquitos showing resistance to pesticides (e.g., DDT) illustrate adaptation.

    • Similarly, some bacteria have developed antibiotic resistance.