1. Ch 16.3 (Pg. 460-464): Darwin Presents His Case

2. Darwin and Alfred Russel Wallace
Alfred Russel Wallace was a naturalist working in Malaysia, who also had similar ideas about evolution
In 1858 Darwin and Wallace co- presented their theory to the Linnaean Society of London
In 1859 Darwin published his book, On the Origin of Species

3. Darwin’s Case for Evolution
Struggle for Existence
More individuals are produced than can survive, and must compete with each other
Variation and Adaptation
Some variations are better suited to the environment than others
Inherited variations that increase an organism’s ability to survive and reproduce are adaptations

4. Darwin’s Case for Evolution
“Survival of the Fittest”
Differences in adaptations affect an individual’s survival
Organisms that are best adapted to their environment survive and reproduce better than others, and have the highest fitness

6. Darwin’s Case for Evolution
Natural Selection
Occurs when:
More individuals are born than can survive
There is natural heritable variation
There is unequal fitness between individuals

8. Descent with Modification
Means that all organisms are descended from a common ancestor
Many generations must pass on traits with slight modifications to create new species