Geo2:Chapter 9

  1. Evolution
    -genetically controlled changes in physiology, anatomy and behavior that occur over time
  2. Clade
    different species with the same ancestor
  3. Speciation
    the development of two or more different species from a single common ancestor species
  4. Gregor Mendel and origin of genetics
    • -father of genetics
    • -Pea experiments
    • -Units of inheritance do not change or blend
  5. Basic principle of genetics
    • 1. Genes
    • -chemical unit of heredity
    • -formed of DNA
    • 2. DNA
    • -a molecule with a double helix structure
  6. Polymorphism
    genetically controlled variation in appearance within a population
  7. Genome
    full range of genes present in a species
  8. Phenotypic variations
    differences in physiology,anatomy, or behavior within a species
  9. Genotypic variations
    genetic differences within a species
  10. Mutations
    random changes in the genes or chromosomes of a cell
  11. Cline
    a geographic gradient in a genetically controlled trait
  12. Hybridization
    sexual reproduction between two different species
  13. Natural Selection
    the process by which the genes for genetically controlled traits become more common in a population over time because individuals with those traits are reproductively more successful than other individuals
  14. Speciation
    The development of two or more different species from a single common ancestor species
  15. Reproductive isolation
    there should be a barrier between a new species and an original species
  16. Environmental controls: ranges of tolerance and ecological optimum
    • 1. Ranges of tolerance
    • -determine where on Earth a species may be found
    • 2. Ecological optimum
    • -the environmental conditions under which a species will prosper
  17. Stasis
    long period of time with no evolutionary changes
  18. Phyletic gradualism
    a slow steady process
  19. Punctuated equilibrium
    speciation occurs within an originally small group, which later expands
  20. Direction in evolution
    There are patterns but no general direction
  21. Geography and evolution: Founder principle, bottleneck
    • 1. Founder principle
    • -small isolated populations have less genetic variation than the main population.
    • -favors allopatric speciation
    • 2. Bottleneck
    • -decrease in genetic diversity as a result of a significant decrease in population size
  22. Vicariance
    geological event of environmental changes that splits a range of species in tow isolated partys
  23. Adaptive radiation
    formation of several species from a single ancestor
  24. Convergent and divergent evolution and examples of
    • 1. Convergent evolution
    • -the development of similar traits in unrelated species living in similar environments
    • Ex. Tenrec and Hedgehog
    • 2. Divergent evolution 
    • -separation of a species into new types
    • Ex. Aardvark, numbat and anteater
  25. Parallel evolution and coevolution
    • 1. Parallel evolution 
    • -geographically isolated populations derived from the same ancestor evolve into morphologically and physiologically similar descendant species
    • 2. Coevolution
    • -two unrelated species evolve traits that are tied to their interaction
  26. Extinction
    total loss of a species, genus, family, or order
  27. Types of extinction
    • 1. Local extinction
    • -a species disappears in one area but persists in others
    • 2. Global extinction 
    • -a species disappears completely
    • 3. Phyletic extinction
    • -when a species/genus evolves into a new species/genus
  28. Trophic cascade
    • the loss an important prey species causes further extinctions for higher predators 
    • Ex. California condor
  29. Living fossils
    • persist without considerable evolutionary changes for a geologically long time
    • -Ex. Atlantic horseshoe
  30. Major extinctions of geologic past
    • 5 largest mass extinction
    • -Most recent is the Cretaceous Tertiary
    • -dinosaurs died
Card Set
Geo2:Chapter 9