Diversity of Life Lecture

Dimensions of Diversity

• Vertical Dimension: Hierarchy from atoms to the biosphere.
• Horizontal Dimension: Diversity of organisms across time, organized through taxonomy.

Taxonomy

• Definition: Part of biology that names, describes, and classifies species based on relationships.
• Origin: Developed by Carl Linnaeus in the 1700s.
• Hierarchical System:
  • Domain (broadest)
  • Kingdom
  • Phylum
  • Class
  • Order
  • Family
  • Genus
  • Species (most specific)
• Mnemonic: King Philip Came Over For Good Spaghetti

Classification Example: Humans

• Domain: Eukarya
• Kingdom: Animalia
• Phylum: Chordata
• Class: Mammalia
• Order: Primate
• Family: Hominidae
• Genus: Homo
• Species: Sapiens
  • Naming Rules: Italicized or underlined, Genus capitalized, species lowercase.

Three Domains of Life

• Bacteria: Diverse and widespread prokaryotes.
• Archaea: Prokaryotes living in extreme environments.
  • Extremophiles: Adapted to extreme conditions (temperature, pressure, pH, etc.).
• Eukarya: Organisms with eukaryotic cells (protists, fungi, animals, plants).

Evolution

• Definition: Process of change that transforms life on Earth from its earliest forms.
• Fossil Record: Documents pattern of ancestry and evolution.
  • Charles Darwin: Proposed natural selection as a mechanism for evolution.
  • Natural Selection: Occurs when:
    1. Individuals vary in heritable traits.
    2. Certain traits offer survival and reproductive advantages.
• Example: Peppered moth evolution during Industrial Revolution.

Phylogeny and Ancestry

• Phylogenetic Trees: Show evolutionary relationships among organisms.
  • Modern Elephants: Analysis of DNA and fossils reveal complex ancestry.
  • New Discoveries: Genetic studies redefine understanding of species relationships.

Key Takeaways

• Natural Selection: Acts on individuals but results in changes at the population level.
• Evolution: Affects populations, not individuals.
• Taxonomy and Phylogenetic Studies: Help in understanding relationships and evolution over time.