Allopatric speciation is when a fraction of a population is geographically isolated and speciates.  Sympatric speciation is speciation in the midst of no geographic barrier.  A subpopulation diversifies while coexisting with the parent population.

What favorably affects allopatric speciation?

1. founder effect (a small population is not representative of the parent population).
2. genetic drift (the neutral allelic combinations might become stable by chance).
3. natural selection (a peripherally isolated subpopulation is facing different environmental stresses).

The hybrid zone is where two allopatric species when they are not isolated anymore.

The Recognition Concept of Species.

Molecular, morphological, and behavioral characteristics of a species are maximized for success reproduction within their population.

The Cohesion Concept of Species.

Hybrid speciation occurs because of different environmental stresses within the hybrid zone.

Two types of evolution are anagenesis (slurring) and cladogenesis (branching).

Punctuated equilibrium = a bunch of primates then "POOF" a humanoid!

Allometric growth is the difference of the relative rates of growth of each body part that helps shape the organism.  Paedomorphosis is a creation of a sexually mature adult keeping features that were juvenile structures of its ancestors due to developmental timing.  This change in the developmental rate and timing is called heterochrony.  Heterochrony is a major part of homeosis.  Homeosis is the development of the organism as coordinated by the homeobox.  The homeobox is a group of genes and gene families that control heterochrony and spatial patterns (the placement of body parts).

Species Selection.

The species that endures the longest and generates the greatest number of new species determines the direction of evolutionary trend - where "new species" equals the birth of an individual and the "extinction of a species" is the death of an individual.

How can phylogeny be determined molecularly?

Assuming the rate of mutation per organism is constant, proteins evolve at different rates but for some proteins (e.g. cytochromes) their evolution is proportional to time.  Therefore, the more time the passes the greater the evolution, difference between the species; and DNA (e.g. restriction mapping, sequencing, chromosome painting) and proteins can determine - relatively speaking - how long ago 2 species diverged.

Next:  "Taxa, Cladistics, Systematics."