1. Change Over Time

2. Evolution
A cumulative change in the characteristics of organisms or populations from generation to generation
Slow process
Many small changes collect to form a new species
Species - group of the same organism, organisms that can breed together

3. Charles Darwin Natural Selection
Observed the main mechanism of evolution on his travels around the world.
Natural Selection

4. Galapagos Islands Island chain off the coast of Peru
Islands vary in terrain and vegetation
Darwin studied finches on several of the islands

5. Galapagos Finches Many different species are found on the island
Each finch is well adapted to their island habitat
How? Why?

7. Darwin’s Theory of Evolution by Natural Selection (OCVSRS)
(Potential for) Overpopulation - Unchecked reproduction causes exponential population growth.

8. Darwin’s Theory of Evolution by Natural Selection (OCVSRS)
Competition - for resources occurs because resources are limited (space, clean water, food, etc…)
Ex. Predator Prey relationship

9. Darwin’s Theory of Evolution by Natural Selection (OCVSRS)
Variation with in a population.
Some organisms may be…
faster or slower,
stronger or weaker,
more resistant to a disease
Blend in with surroundings better
Etc.

10. Darwin’s Theory of Evolution by Natural Selection (OCVSRS)
Selection - some variations increase the chance of survival because they
Out run a predator
Hide from a predator
Find clean water
Use different food sources
Etc..

11. Darwin’s Theory of Evolution by Natural Selection (OCVSRS)
Reproduction - organisms that are selected for survival can pass on their traits
Over time the frequency of favorable traits will increase in the population

12. Darwin’s Theory of Evolution by Natural Selection (OCVSRS)
Speciation - Process of forming a new species
Over time many changes accumulate
If populations are different enough that they can no longer mate with each other. The two populations are considered different species.