1. Unit 3 Evidence of Evolution and Biodiversity
Part 3
Evolution and Natural Selection

3. Who was Charles Darwin Studied medicine
Hated the sight of blood
Darwin was a Naturalist who studied plants and animals

4. Theory of Evolution
Darwin set sail on the HMS beagle where he studied many different plants and animals
Darwin learned that similar looking species lived close to each other and proposed that species do change over time
The Theory of evolution is based on the idea that species are all related and change over time

5. “Natural Selection” Darwin’s Finches
In The Galapagos Islands, Darwin collected species of finches (13)
Each had a specialized diet and beak structure
These finches all closely resembled a South American finch ancestral species
On the trip Darwin saw things he could only attribute to a process called:
“Natural Selection”

6. Darwin called this process by which populations change in response to their environment:
Natural Selection

7. Darwin’s Finches

8. Natural Selection is based on these inferences:
There is variation within populations
Some variations are favorable
Not all young produced in each generation can survive
Individuals that survive and reproduce are those with favorable variations
Favorable traits will increase in future generations.
Survival of the Fittest

9. Types of Evolution Adaptive Radiation Divergent Evolution Co-Evolution
Convergent Evolution

10. Adaptive Radiation
Evolution of many diverse species from one common ancestor
Ex: famous Galapagos finches discovered by Darwin

11. Divergent Evolution (spread apart)
-Isolated populations evolve independently
Ex: polar & grizzly bears changed independently due to different habitats

12. Coevolution (together)
-Species that interact closely adapt to one another
Ex: Flowers & Pollinators
(Birds, Bees and Butterflies too)

13. Convergent Evolution (come together)
-Unrelated species become more alike because they live in similar environments
Ex: shark & dolphin

14. Speed of Evolution?
2 thoughts

15. Gradualism
The idea that species evolve slowly and continuously over long periods of time, or “gradually”

16. Punctuated Equilibrium
evolution occurs primarily through short bursts followed by lengthy periods of stasis. We see this in fossil data.