Evidence of Evolution

• Comparative Anatomy

  • focuses on studying the differences and similarities between the anatomy of organisms.
• Pieces of Evidence

  1. Fossil Record
  2. Artificial Seleciton
  3. Geographic Distribution
  4. Homologous and Analogous Structures
  5. Molecular Homologies
  6. Embryology
• Fossil Record

  • Different traces of remains of an organism change over time and are preserved by NATURAL PROCESSES.
• Artificial Selection

  • Species variation occurred through mutation and sexual reproduction, but human select features that are beneficial.
• Geographic Distribution

  • Organisms that were closely related but different species traveled into surrounding habitats and evolved in these far-apart geographic regions.
• Geographic Distribution

  1. Convergent Evolution - organisms that are closely related, yet, different species that live in different geographic locations evolve similarly and adapt to the same environment.
  2. Divergent Evolution - Due to differential selection pressure, species with a common ancestor grow increasingly divergent, eventually leading to speciation.
• Homologous Structures

  • Different organisms' structures evolve from a common ancestor.
  • Same structure, different function.
• Analogous Structure

  • structures with similar functions even though they evolve independently between different species.
  • Same function, different structures and species
• Vestigial Organs

  • Physical and behavioral characteristics of organisms that have no longer been used over time.
• Molecular Homologies

  • All living things share the same genetic structure (DNAs and RNAs)
  • DNA - organisms that are more closely-related share similar sequences.
• Embryology

  • Embryos of vertebrates develop in the same way.
  • The similarities between embryos of various species can be used for tracking evolutionary relationships.
• Embryology

  • Human embryo has a tail in the 4th week but disappears during the 8th week.
  • Pharyngeal pouches become gills in fish, and part of the throat/ears in humans.
• Where Natual Selection Are Evident:

  • Bird Flu
  • Tuberculosis
  • HIV/AIDS
  • COVID-19
• Evidence of Evolution

  • Structural Evidence
  • Homologous and Analogous
  • Vestigial Structures
  • Embryonic Evidence
  • Molecular Evidence
  • DNA Sequence
  • Proteins