### process | phylogeny:

Speciation
* Most speciation increases biological diversity
* Most speciation occurs in geologic time
  - over time
  - produces diversity
* Some speciation occurs in cycads.
* also can occur when geographic boundaries split populations from one another.
* can also occur when a subpopulation migrates into a new niche.
* can occur in only a single generation
  - when two populations occupy different habitats
  - result from isolation
* common occurance in nature.
* explains evolutionary branching and diversification.
* generally requires barriers to gene flow.
* happens almost on a daily basis
  - to populations
* involves changes to more than one gene
  - many mutations leading to significant changes
* is an absolute necessity for evolution to be valid.
* is an evolutionary event that gives rise to new species
  - process in which one species splits into two or more species
  - extension of evolution
  - incredibly important edict of evolution
  - ongoing process that has resulted in a spectacular diversity of flora and fauna
  - at the boundary between microevolution and macroevolution
  - different from evolution
  - evidence of evolution
  - how a new kind of plant or animal species is created
  - often the result of environmental adaptation
  - one of the most basic processes in evolution
  - responsible for the great diversity of species in our nature
* is the attainment of reproductive isolation
  - development of a new species
  - division of one species into two different species
  - formation of new species from older species
  - mechanism by which different species are created from the same ancestral species
  - name for the process by which one species branches into two or more new species
* is the process by which new biological species arise
  - species are formed
  - of evolution by which new species form
  - where daughter species evolve from the parental species
  - separation of one lineage into two
  - very important in evolutionary biology
* leads to the creation of two independent populations.
* means reproduction can only take place between members of the same species.
* occurs at the periphery of the population
  - because of reproductive isolation
  - several stages
  - naturally over a very long time
  - through changes in chromosome number resulting in reproductive isolation
* occurs when one population is isolated from another population
  - two populations become reproductively isolated
* phenomena in birds.
* processes in the adaptive radiation of Hawaiian plants and animals.
  - the diversity that phylogenetic biologists document
* requires reproductive isolation
  - selective mating, which result in a reduced gene flow
* results from selections
  - sexual selections
  - in two species derived from a single progenitor species
* takes place in geographically overlapping populations.
* tends to be favored by catastrophic events on earth.

### process | phylogeny | speciation:

Allopatric speciation
* Most allopatric speciation produces diversity.
* begins when a population becomes geographically separated.
* is especially common on island chains
  - suggested to be the major mode of speciation in the clade
  - the easiest to understand, particularly on oceanic islands
* needs a geographical barrier separating populations.
* takes place when two populations are geographically isolated.

Peripatric speciation
* critical underpinning of the theory of punctuated equilibrium.
* subset of allopatric speciation.