THE ORIGIN OF SPECIES

What is a species?

Morphological Species Concept - used in taxonomy and paleontology

Biological Species Concept

REPRODUCTIVE ISOLATION.
Isolating Mechanisms - Table 17.2a and Table 17.2b

     Prezygotic

- Geographic

- Ecological Fig 17.20

- Temporal

- Behavioral - Image

- Mechanical - beetle and genitalia

- Gametic

Postzygotic - Fig 17.21

- Reduced hybrid viability

- Reduced hybrid fertility (Sterility)

SPECIATION MODELS - A comparison - Image

   - Allopatric speciation. - Image Geographic isolation - Image Fig 17.22

Adaptive radiation - Image An example - Image

   - Sympatric Speciation.

TEMPORAL ASPECTS OF EVOLUTION (Image) Fig 17.2

    - Gradualism

    - Punctuated Equilibrium

Micro evolution vs. MACROEVOLUTION   Macroevolution - the Movie!

- Modified versions of older structures - mollusk eyes - Image