BIO 3400 Scioli
Summer II 1999

Objectives / Review for Exam III - new material, part 4

1. Species concepts (a sample)
   1. folk species
   2. biological species
   3. phenetic / morphological species
   4. phylogenetic species
2. Phylogenetics
   1. phylogenetic - pertaining to the evolutionary relationships within and between groups
   2. anagenesis - progressive evolution toward higher specialization
   3. cladogenesis - branching of a phylogenetic tree (divergence into two separate groups and subsequent divergence)
   4. stasis - periods of no perceptible phenotypic change
   5. phyletic gradualism - a model of evolution in which species change gradually
   6. punctuated equilibrium - a model of evolution in which species retain the same phenotype for long periods until sudden phenotypic change results in speciation
   7. convergence
3. Constructing phylogenies
   1. Character state
      1. ancestral (primitive)
         1. plesiomorphic
         2. if shared, symplesiomorphic
      2. derived
         1. apomorphic
         2. if shared, synapomorphic
   2. Classification
      1. phenetic (based on shared characters, overall phenotypic similarity) classification generates phenogram
      2. cladistic (based on shared-derived characters) classification generates cladogram
      3. evolutionary classification attempts to include both phenetic and cladistic ideals to overcome deficiencies of each
   3. Goals
      1. to produce monophyletic groups (groups composed of all descendants of common ancestor) from which evolutionary history may be inferred
         1. monophyletic grouping
         2. paraphyletic grouping
         3. polyphyletic grouping
      2. to produce parsimonious classification
   4. Potential difficulties in building evolutionary classifications
      1. polyphyletic groups due to convergent evolution, parallel evolution
      2. inconstant rates of evolution across taxa
      3. conservative characters
         1. general adaptations vs. specialized adaptations
         2. developmental constraints (canalization)
      4. determining which are homologous vs. analogous characters
         1. homologous characters are inherited by two or more species from a common ancestor
         2. homoplasy occurs when a character state evolves more than once in a lineage and is not possessed by all descendants
            1. convergent evolution
            2. parallel evolution
            3. evolutionary reversals (Dollo's rule: Once lost, more complex structures are less likely to be regained)
      5. determining ancestral vs. derived characters
         1. outgroup analysis
         2. developmental history (embryology)
            1. Biogenetic Law (Haeckel 1866): Ontogeny recapitulates phylogeny.
            2. or, more accurately, von Baer's Law: Early developmental stages of a characteristic tend to be more similar among related species than later stages
      6. molecular clock
   5. Parsimony (Ockham's razor or Occam's razor): the principle of accounting for observations with the hypothesis that requires the fewest or simplest assumptions (for which evidence is lacking); usually involves the minimum number of evolutionary changes
4. Geographic patterns
   1. General observations
      1. Bergmann's Rule - body size in animals tends to increase toward the colder part of their range
      2. Allen's Rule - extremities in mammals tend to shorten toward the colder part of their range
      3. Cope's Rule - body size within a lineage tends to increase through time
      4. Gloger's rule - skin pigmentation is heavier in warmer, more humid parts of an animal species' range
      5. Rapoport's rule - species adapted to cooler climates are distributed along a wider range of latitudes than species adapted to warmer climates
   2. Survivors of mass extinctions tend to be generalists rather than specialists (evidence from foraminifers, bryozoans and molluscs)
5. Neutral variation / hidden variation
   1. protein electrophoresis
      1. isoenzymes
         1. R.C. Lewontin and J.L. Hubby (1966)
         2. E. Nevo (1988)
      2. more possible isozymes results from
         1. more alleles in a population
         2. enzyme structural complexity (monomeric, dimeric, trimeric, etc.)
   2. DNA sequencing
6. Natural selection
   1. adaptation / imperfection
   2. constraints
      1. supergene
      2. allometric growth
      3. developmental canalization
   3. sexual selection [read Scientific American article!!!]
      1. runaway evolution
      2. driven by female choice
      3. not necessarily in male's best interest
      4. examples
         1. Trinidad guppy - blue versus orange coloration
         2. tail length in peacocks and birds-of-paradise
   4. kin selection
      1. different definitions of altruism (Ridley, p. 321 - 322)
      2. direct reproductive disadvantage outweighed by increased inclusive fitness
      3. examples
         1. social insects - ants, social bees and wasps
         2. Florida scrub jay
   5. group selection
   6. species selection
7. Community ecology and the ecology of invasion
   1. What regulates species assemblages in a particular habitat type at a particular time?
      1. deterministic factors?
      2. random / stochastic factors?
      3. combination of both?
   2. Coexistence may be a result of the ghost of competition past
      1. F. Gause's principle of competitive exclusion
      2. niche structure
         1. single resource axis
         2. multiple resource axes (hyperdimensional niche structure - G.E. Hutchinson)
         3. Liebig's Law of the Minimum
      3. resource partitioning reduces competition
      4. character displacement
8. MacArthur-Wilson island biogeography model (Robert H. MacArthur and Edward O. Wilson. 1967.)
   1. How many mainland species should we expect to see on an island?
   2. The answer depends, in part, on the size of the island and its distance from the mainland.
      1. area effect
      2. distance effect
   3. The equilibrium number of mainland species that are expected on the island is a balance between species arrival and species extinction.
      1. immigration / arrival rate
      2. extinction rate
   4. The MacArthur-Wilson island biogeography model applies to island analogs, too.
      1. mountain tops
      2. isolated alpine meadows
      3. lakes, ponds
      4. divided forests
      5. national park / wildlife refuge subdivisions
9. Coevolution / coadaptation (there exist too many examples to list all that were discussed)
   1. predator - prey
      1. parallel phylogenies [cospeciation]
         1. mammals (pocket gophers) and their arthropod parasites (chewing lice)
   2. mimicry / camouflage
      1. aposematic coloration
      2. defensive
         1. Batesian mimicry
         2. Mullerian mimicry
      3. offensive / aggressive
   3. moment-of-truth defenses
      1. eye-spots
      2. toxic sprays
      3. change in size
   4. parasite - host, pathogen - host
   5. mutualisms
      1. pollinator - plant
      2. disperser - fruit
      3. nitrogen-fixing bacteria and legume roots
      4. mycorrhizal fungi and plant roots
      5. gut bacteria and ruminants
      6. gut protozoan and cockroach / termite

This is not intended to be an exhaustive transcript of everything discussed in class; however, major topics not listed here will not be covered on the exam. It is intended as a guide to help in your preparation for the exam. When in doubt about the details, look first to your class notes, then check out the index at the back of your textbook(s).

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