Chapter 26

• Biodiversity - all of the diversity/variety of life on Earth
• Systematics - study of evolutionary relationships between organism(s).
• Taxonomy - the science of naming organisms
• Taxon - a named group of organisms
• Classification - assigning organisms to meaningful, hierarchical groups (like genera or families)
• Phylogeny - evolutionary history of an organism(s) where things originate; ancestry
• Hierarchical Classification:

  • Domain
  • Kingdom
  • Phylum
  • Class
  • Order
  • Genus
  • Species
• Inferences of genetic relationships:

  • Morphology - characteristics/ what an organism "looks" like
  • Genes - what genes are shared between organism(s)? What genes are different?
  • Biochemistry- what enzymes/molecules are shared? Different?
• Analogy - phenotypic and genetic similarities without shared ancestry due to convergent evolution
• Divergent vs. Convergent evolution

  • Divergent - Occurs when two groups of the same species evolve different traits within those groups in order to accommodate for differing environmental pressures.
  • Convergent - Occurs when similar environmental pressures and natural selection produce similar (analogous) adaptations in organisms found in different evolutionary lineages.
• Cladistics Terms:

  Paraphyletic - Consists of an ancestral species and SOME of its descendants.

  Polyphyletic - Includes distinctly related species but does not include the common ancestor.
• Correctly label the images:

  A) Polyphyletic

  B) Paraphyletic

  
• Plesiomorphy

  • An ancestral characteristic.
  • A trait that is found in the common ancestor, and is passed on to some, if not all, groups.
• Apomorphy

  • A derived characteristic (changed from ancestor to something very different).
  • A specialized trait/character that is unique to a group or species.
• Symplesiomorphy

  • Shared, ancestral characteristic
• Synapomorphy

  • Shared, derived characteristics
  • There should be at least one of these for each taxonomic group, because that is what links them to the previous group.
• Homoplasy

  • An analogous trait or character
  • Two or more of the same characteristic show up in random places in a phylogenic tree (example: eyes)
• Gene Families - groups of related genes within an organism's genome
• Orthologous Genes -similar genes found in different species
• Paralogous Genes - differing genes in similar species
• Rates of Evolution:

  • Horotely - Normal rate of evolution
  • Tachytely - Fast rate of evolution
  • Bradytely - Slow rate of evolution
• 3 Domains of Life:

  • Bacteria
  • Archaea
  • Eukarya