1. Evidence for Evolution

2. FOSSILS
Fossils are preserved parts of animals, plants, and other organisms from the distant past
They show CHANGE OVER TIME

3. Radioactive elements in:

4. Wikipedia Explains….
Most chemical elements are stable: If they are not part of a chemical reaction, they do not change.
Chemical elements are made of atoms. In stable elements, the atom stays the same.
In the 19th century, Henri Becquerel discovered that some chemical elements have atoms that change: During their change they send out a (radioactive)particle.
In 1898, Marie and Pierre Curie called this phenomenon radioactive decay.

5. Fossil Age – Radioactive Decay
The half-life of a substance is the time it takes for half of the substance to decay

6. Vestigial Structures
Structures that have lost their use through evolution
provide evidence for evolution because they suggest that an organism changed from using the structure to not using the structure, or using it for a different purpose
common ancestor!
Ex: Penguins using wings to swim, not fly.
Ex:Appendix, wisdom teeth, tail bone

7. Homologous Structures
structures that occur in different species that originated by heredity from a common ancestor.

8. Evidence from Embryos
Gill slits
Gill slits
Common ancestor!

9. DNA similarities
Molecular clocks are used to determine how closely two species are related by calculating the number of differences between the species' DNA sequences or amino acid sequences.
The fewer the differences, the less time since the species split from each other and began to evolve into different species
Ex: All organisms that use oxygen have the enzyme cytochrome c.

10. Types of Evolution CONVERGENT DIVERGENT
NOT from recent common ancestor
Look similar because evolved to live in the SAME environment.
Came from COMMON ANCESTOR.
Look different because they evolved to live in different environments.