1. Date: April 7th, 2017
Aim # 65: How does geographic and reproductive isolation lead to speciation?
HW:
Daily Review of class notes.
Whales in the Making Article
Do Now: Define and give an example of the following…
Homologous structures
Analogous structures
Vestigial structures
How do scientists use DNA and Amino Acid sequences to compare species?

2. Aim #65: How does geographic & reproductive isolation lead to speciation?

3. 1) Speciation
Evolution has lead to the formation of new species from different ancient organisms.
Species- a group of organisms that
share certain characteristics & can
mate with one another, producing
fertile offspring.
Population- all the individuals of a
single species that live in a specific
area.

4. 2) What was Darwin’s explanation for evolution?
NATURAL SELECTION
HOW DOES EVOLUTION REALLY WORK?

5. Natural Selection
According to Darwin nature controls evolution, the environment selects the characteristics best suited for survival in a particular area.

6. 3) Geographic Isolation
The idea that two populations of the same species of organism can evolve separately because of a geographic barrier.
Physical barriers
Mountains
Bodies of water
Lakes

7. Agents of Evolution

8. 4) How does Geographic isolation lead to Speciation?
Those who have an adaptive variation will survive & reproduce in the different environments. This leads to different species with different variations.

9. 5) Darwin’s Finches (An Example of Geographic Isolation)
All came from a common ancestor & due to different environments on each island, new species evolved that were adapted to their particular environment

10. 6) Adaptive Radiation
Evolution of many species from one common ancestor due to natural selection

11. Adaptive Radiation
Each group of finches adapted to its new environment,
and through the process of natural selection, became
different enough that interbreeding became impossible.

12. 7) Reproductive Isolation:
A reproductive barrier keeps similar species from interbreeding.
Timing- two similar species may have different
breeding seasons.
Behavior- two similar species may have different
courtship or mating behaviors.

13. 8) How long does evolution take?
Evolution takes a long time, but if the environment changes suddenly, evolution will be faster

14. Patterns Of Change
Species with SHORT reproductive cycles that produce MANY offspring tend to evolve more quickly than species with LONG life spans and FEW offspring.
Types:
Gradualism – evolution occurs steadily through time (Slow & Continuous) .
Punctuated Equilibrium- species stay the same for long periods of time and then change rapidly.
No Change
No Change
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