1. Formation of Species 16.3 pp. 309-312
Speciation = formation of new species of organisms by evolving from an ancestor
Morphological Concept:
Morphology = internal & external structure and appearance
Morph = change the look
Plus: Convenient, works with extinct species
Minus: Easy to make mistakes
Populations evolve, individuals do not evolve.

2. Formation of Species 16.3 pp. 309-312
Biological Species concept = individuals of a population can successfully interbreed and cannot interbreed with other populations
Offspring are fertile
Plus: testable for living species; improved by DNA analysis
Minus: can’t apply to non-living organisms
Not this case:

3. Formation of Species 16.3 pp. 309-312
Isolation = populations are separated which may lead to speciation Ways to separate: Geographic isolation = different places Temporal isolation = different times Reproductive isolation = don’t mate

4. Formation of Species 16.3 pp. 309-312
2 categories of Reproductive Isolation:
1. Prezygotic = before fertilization (before a zygote)
Different behavior
Different times (temporal)
Different habitats (geographic)
2. Postzygotic = after fertilization (after a zygote)
Mutation
Infertility of offspring

5. Formation of Species 16.3 pp. 309-312
Rates of Speciation = how fast does a new species evolve
Rough average is 1 every million years but this can vary greatly
Depends on selection pressures in the environment

6. Formation of Species 16.3 pp. 309-312
Rates of Speciation
Gradualism = slowly over time (~ million years)
Mutation
Isolation
2. Punctuated Equilibrium = periods of sudden evolution caused by extreme selection pressures, followed by periods of no evolution
(~ thousands of years)