Evidence of Evolution and Common Ancestry

Evidence of Evolution and Common Ancestry

Page 1: Overview of Evolution

• Key Concept: Evidence supporting the theory of evolution is profound and diverse.
• Primary Sources of Evidence:
  • Fossil Record
  • Comparative Morphology
  • Biogeography

Page 2: Fossil Record

• Fossils: Remains or traces of past organisms.
• Fossil Record: Provides a visual illustration of evolutionary changes over time.
  • Dating Fossils: Use of carbon-14 decay rates and the geological context of rocks.
  • Geographical Data: Offers insights into the various organisms found in different locations and times.

Page 3: Comparative Morphology

• Comparative Morphology: Study of structural similarities between living and extinct organisms.
  • Homology: Similar characteristics in different species, potentially serving different functions.
  • Embryonic Homology: Similar embryonic developments across many species.
  • Vestigial Structures: Structures retained through evolution despite lack of functional use.
    • Examples: Tailbone and appendix in humans.
  • Molecular Homology: Shared DNA and amino acid sequences among various species.

Page 4: Homologous Structures

• Homologous Structures: Features that are similar in two species due to shared ancestry.
  • Example: Arm bone structures in mammals (e.g., human arms and whale flippers).

Page 5: Convergent Evolution

• Convergent Evolution: Similar adaptations arising in unrelated species due to analogous environmental pressures.
  • Analogous Structures: Structures that serve similar functions but do not share a common evolutionary origin.
  • Examples: Wings of birds, bats, and insects (bees).

Page 6: Structural Evidence of Common Ancestry

• Eukaryotic Common Ancestry: Structural and cellular features indicative of a shared ancestor among eukaryotes.
  • Key Features Across Organisms:
  • Presence of membrane-bound organelles
  • Linear chromosome structures
  • Introns in genes

Page 7: Biogeography

• Biogeography: Study of the geographical distribution of flora and fauna.
  • Examples:
  • Species on oceanic islands closely resemble those on nearby mainland.
  • Distinct species variations on different continents indicate geographical separation.

Page 8: Quick Review

1. What type of data provides evidence for evolution?
   • Answer: Fossil data, biogeography, and comparative morphology.
2. In terms of natural selection, how can structures become vestigial?
   • Answer: Structures may have been useful at one time but became nonfunctional due to mutations, thus conserved over generations without being beneficial or detrimental (neither selected for nor against).

Page 9: Evolution in Populations

• Ongoing Evolution: Populations continue to evolve.
  • Genomic Changes Examples:
  • Antibiotic resistance in bacteria.
  • Insect resistance to pesticides.
  • Emergence of new diseases from pathogens.