1. Journal #3- Darwin described natural selection in his book, On the Origin of Species, in the following way: “I have called this principle by which each slight variation, if useful, is preserved, by the name Natural Selection.” -What did Darwin mean by the terms variation and preserved? *Illustrate: Adaptation, Survival of the Fittest, and Natural Selection

2. 15-3 Darwin Presents His Case (Interactive 378-386)

3. Darwin's Findings
The Galapagos “mockingbirds” were actually 3 different species found nowhere else
The brown birds were all finches. (Darwin thought they were wrens, warblers, and blackbirds)
The island animals found on the Galapagos looked a lot like the ones found on the South American Mainland, but were different species

4. Publication of On the Origin of Species
Darwin waited over 20 years to publish his findings
1858 Alfred Russel Wallace wrote a short essay on Evolutionary change
1859 Darwin published On the Origin of Species
Explained how evolution occurs through natural selection
Very controversial at the time/ Now???

5. Inherited Variation & Artificial Selection
Heritable or Genetic variation is used to improve crops or livestock
Artificial Selection
Nature provides the variation
Humans select those that are useful to produce

7. Evolution by Natural Selection
Struggle for Existence
High Birth rates
Competition for resources
Survival of the Fittest
The ability to survive and reproduce in the given environment
Result of adaptations that increase survival
Organisms with these adaptations live to produce more offspring while those that do not have them die or have few offspring

8. Natural Selection cont...
Results in changes in the inherited characteristics of a population
These changes increase a species' fitness in it's environment
Descent with modification
Over long periods
Species change features as a result of occupying new habitats
Each descended from other species

10. Common Descent
The theory that all organisms descended from a common ancestor
Tigers, panthers, cheetahs
Farther back: a single tree of life that links all living things

11. Evidence of Evolution Fossils
Showed life on earth has changed over time
Distribution of Living Things around the world
Animals in similar environments in different parts of the world had similar features
Homologous (similar) body structures
ex. the arms, wings, legs, fins of reptiles, birds, and mammals are all constructed from the same basic bones
Similarities in Embryology
Embryos of varying life forms look very similar during development

12. Fossil Evidence

13. Geographic Distribution

14. Homologous Body Structures

15. Similar Embryonic Development

16. Darwin's 5 Points Populations have variations (individual differences)
Some variations are favorable (best suited to their environment)
Organisms produce more offspring than can survive, and they must compete for resources
Those that survive have favorable traits and produce more offspring to carry the trait or traits
A population will change over time