1. Daily Warm-up February 25th What do you think defines a species
Daily Warm-up February 25th What do you think defines a species? HW: Read Turn in: Pre-registration form

2. Species Two types What is a species?
Members of a population that are able reproduce fertile offspring
Speciation: process whereby some members of a population change so much that they can no longer produce fertile offspring
Reproductively isolated
Two types

3. Prezygotic Isolation
Prevent reproduction by making fertilization unlikely
Behavior, ecological, geographical, timing
ecological isolation
temporal isolation
geographic isolation
behavioral isolation
mechanical isolation
gametic isolation

4. Postzygotic Isolation
When fertilization occurs but a hybrid offspring cannot develop or reproduce

5. Speciation If reproductively isolated for long enough time…speciation
Allopatric speciation
Physical barrier separates a population into two or more populations
Sympatric speciation
Evolves into a species without a physical barrier

7. Geographic isolation Species occur in different areas physical barrier
Ammospermophilus spp
Species occur in different areas
physical barrier
allopatric speciation
Harris’s antelope squirrel inhabits the canyon’s south rim (L). Just a few miles away on the north rim (R) lives the closely related white-tailed antelope squirrel

8. Patterns of Evolution Speciation is a long process
Evidence of speciation is visible in patterns of evolution
Adaptive radiation
Coevolution
Species evolve in close relationship with another species
Convergent evolution
Unrelated species evolve similar traits because of a similar climate even though in far away places.

9. Adaptive Radiation
New habitat leads to rapid speciation

10. Coevolution
Two species evolving in close relationship with other species.
Might be so close that the evolution of one species affects the evolution of other species.
Mutualism, parasitism

11. Rates of Speciation Punctuated Equilibrium
Gradualism
Punctuated Equilibrium
gradual accumulation of small changes over long time
rapid bursts of change mixed with long periods of little or no change