1. Evidence for Evolution

2. Changing Environments Select for Specific Genetic Phenotypes
Before the Industrial Revolution the trunks of certain trees were a light color. The lighter peppered moths had an advantage over the darker moths. The lighter moths were more likely to survive and reproduce so there were more of them in the population. However, with the Industrial Revolution came pollution. The trees turned dark. Now the darker moths had the advantage. Adaptations are dependent upon the environment.

3. Fossils The Fossil record shows patterns of development
It demonstrates that species have physically changed over long periods of time and diverged from common ancestors

4. Law of Superposition
Fossils found in the lower rock strata are older than those found closer to the top.

5. 2. Vestigial Structures
These are structures still present in an existing species.
However, they are reduced in size or function even to the point of serving no function whatsoever. (ex. wisdom teeth and appendix in humans, wings in flightless birds)

6. Vestigial Structures continued
Vestigial structures support the theory of evolution by showing that species adapt to changing needs, leaving unnecessary organs behind.

7. 3. Homologous Structures
Homologous structures refer to anatomical similarities in different species, despite the function of the structure.
Example: A bat’s wing and a human’s arm serve very different purposes, however, they share an almost identical bone structure.

8. Homologous Structures continued

9. Homologous Structures continued
Homologous structures support the theory of evolution because they demonstrate that different species often share a common ancestor

10. 4. Analogous Structures
Analogous structures share similar functions but have very different anatomy.
Example: A bat’s wing and a bird’s wing serve the same purpose: flight. However, the bone structure of a bat’s wing is more similar to a human arm than a bird’s wing.

11. Analogous Structures continued

12. Analogous Structures continued
Analogous structures support the theory of evolution by demonstrating that very different species will form similar adaptations in the face of similar environmental pressures.

13. 5. Embryology
The earliest stages of embryonic development show astonishing similarities between species.
This shows that the activated genes are very similar. This is corroborated by genetic sequencing.

15. Embryology continued
Embryology supports the theory of evolution by showing that the genes activated earliest in an organism’s development have remarkably similar effects regardless of the species.

16. The tree of life has branched in countless different directions
The tree of life has branched in countless different directions. However, we all came from the same roots.