taxonomic terms table 20&21 final exam.txt

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taxonomic terms table 20&21 final exam.txt
2011-12-11 11:00:00
taxonomic terms

evolutionary bio
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  1. Table 18
  2. Autoplesiomorphy
    • ONLY the descendent (earliest ancestor) shows trait
    • ie, reptilia have incomplete 4-chambered heart, while descendent classes (including aves and mamilia) retain complete 4-chambered heart --> the derived trait
  3. Symplesiomorphy
    • in monophyletic tree, 2 or MORE descendent taxa (as well as ANCESTRAL taxon) retain ancestral trait
    • ie, use of tetrapod limbs is first seen in amphibians and is retained (embryonically) in all 3 descendent taxon
  4. Autoapomorphy
    • ONLY descendent taxon (NOT earliest taxon) retains derived trait
    • ie, use of feathers for flight in Archaeopteryx (not present as ancestral trait)
  5. Synapomorphy
    • in monophyletic tree, 2 or MORE descendent taxon (NOT earliest descendants) retain derived trait
    • ie, monodermata & didermata retain cell wall (derived trait) while ancestral Archaeobacteria does NOT
  6. monophyletic
    • group of ONLY common ancestors & all of descendants
    • ie, class Aves, Archaeopteryx is believed to be first feathered bird for flight…ancestor to all modern birds
  7. Paraphyletic
    • Taxonomic group consisting of ONLY common ancestor and SOME of its descendants
    • ie, Class Reptilia: including turtles, lizards, snakes, EXCLUDING mammals and birds, although they evolved @ same time as reptile
  8. Polyphyletic
    • group that does NOT include either the common ancestors or all of its descendants. Includes MORE than one ancestor
    • ie, class Insecta (Hexapoda) w/collembolids or springtails evolving from maxillopod & others evolving from malacostracans
  9. Homologous
    • SIMILAR structures (w/Diff FXNS) due to common ancestry
    • ie, albatross WINGS adapted for FLIGHT & penguin flippers adapted for SWIMMING
  10. Analogous
    • aka homoplasious
    • Can have different structures (w/SIMILAR uses) due to similar environments
    • ie, dorsal fin on dolphin (mammal) and shark (cartilaginous fish) both adapted different but fxn to stabilize
  11. Homoplasy from parallelism
    • Similar uses in 2 descendants, but NOT common ancestor.
    • Similar structures may be in all 3
    • ie, toothless snout of spring echidna (monotrem) and anteater. These both adapted to same environment, but ancestor HAD TEETH
  12. Homoplasy from convergence
    • similar uses in 2 descendants, but NOT in common ancestor
    • DIFFERENT structures in 2 descendents
    • ie, hummingbird wings adapted for flight & butterfly wings also adapted for flight. BOTH used to escape predators or find food, although embryologically different structures.
  13. Homology
    • if 2 descendants, and common ancestor also has same structure, BUT…1 descendent has DIFF use for structure than other
    • ie, Archaeopteryx (ancestor) and albatross (descendent) use forelimb for flight, while penguin (descendent) uses for SWIM
    • (can also have descendent and ancestors all have diff uses (ie, forelimb of mammal, bat and dolphin)
  14. Parallelism
    • if 2 descendants w/same USE for the same structure, but use differs from common ancestor. All have same structure
    • ie, necks of ancestral reptile which are shorter for carnivorous diet, but brachiosaurus and giraffe have their necks longer used for herbivorous diet of treetop leaves
    • also the anteater and echidna are toothless and their ancestor has teeth to eat foods
  15. Convergence
    • if 2 descendants have SAME use for DIFF structures
    • the ancestor may have a different structure from one or both
    • ie, flattened thorax of flatworm (for swimming) is different than the disc wing of butterfly (for flight) and hummingbird forelimb wings (for flight)