unit 4

  1. adaptation
    an inherited characteristic that enhances and organisms ability to survive and reproduce in a particular environment
  2. adaptive radiation
    period of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill new or vacant ecological roles in their communities.
  3. algae
    a protist that produces its food by photosynthesis
  4. binomial
    a two-part latinized name of a species; for example, homo sapeian
  5. bottleneck effect
    genetic drift resulting from a drastic reduction in population size; typically, the surviving population is no longer genetically representative of the original population
  6. clade
    a group of species that includes and ancestral species and all its descendants
  7. cladistics
    an approach to systematics in which common descent is the primary criterion used to classify organisms by placing them into groups called clades
  8. endosymbiosis
    a process by which the mitochondria and chloroplasts of eukaryotic cells probably evolved from symbiotic associations between small prokaryotic cells living inside larger cells
  9. evolution
    descent with modification; the idea that living species are descendants of ancestral species that were different from present-day ones; also the genetic changes in a population over generations
  10. evolutionary tree
    a branching diagram that reflects a hypothesis about evolutionary relationships among groups of organisms
  11. extinction
    it irrevocable loss of a species
  12. founder effect
    genetic drift that occures when a few individuals become isolated from a larger population, whit the result that the composition of the new population's gene pool in not reflective of that of the original population
  13. gene flow
    the transfer of alleles from one population to another, as a result of the movement of individuals or their gametes
  14. gene pool
    all the alleles for all the genes in a population
  15. genetic drift
    a change in the gene pool of a population due to chance; effects of genetic drift are most pronounced in small populations
  16. homology
    similarity in characteristics resulting from a shared ancestry
  17. hybrid zones
    a geographic region in which members of different species meet and mate, producing at least some hybrid offspring
  18. macroevolution
    evolutionary change on a grand scale, encompassing the origin of new taxonomic groups, evolutionary trends, adaptive radiation, and mass extinction
  19. microevolution
    a change in a populations gene pool over generations
  20. parsimony
    in scientific studies, the search for the least complex explination for an observed phenomenon
  21. polyploidy
    an organism that has more than two complete sets of chromosomes as a result of and accident of cell division
  22. protists
    a member of the Kingdom Protista. most protists are unicellular, though some are colonial or multicellular
  23. protozoan
    a protist that lives primarily by ingesting food;a hererotrophic, "animal-like" protists
  24. sexual dimorphism
    marked differences between the secondary sex characteristice of males and females. pecocks
  25. symbiosis
    a close association between organisms of two or more species
  26. taxon
    a named taxonomic unit at any given level of classification
  27. taxonomy
    the branch of biology that identifies, names, and classifies species
Card Set
unit 4