1. The main lines of evidence of evolution are:
Fossil Record
Homologous Structures
Vestigial Structures
Embryology
Similarities in DNA

2. Fossil Record
It is possible to find out how a particular group of organisms evolved by arranging its fossil records in a chronological sequence
Provides evidence of changes in species over time

4. Formation of Fossils
Fossils form when an organism dies and becomes buried in sediment
With a lack of oxygen, the organism does not decay and the minerals in the sediment replace the organic materials of the organism
This turns the dead organism into solid rock
Also why fossils are almost always only found in layers of sedimentary rock

6. Types of Fossils Molds and Casts Most common
Molds leave hollow impression
Casts are a solid copy of the organism

7. Types of Fossils Petrified Fossils
Minerals replace part or all of the organism
Ex- petrified wood

8. Types of Fossils Trace Fossils
Provide evidence of a once living organism
Ex- footprints, burrows, dun

9. Types of Fossils Preserved Remains
A process that preserves an organisms with little of no change
Ex- amber, ice, tar

10. Homologous Structures
Similar structures in different organisms that develop from the same embryonic tissue
Provides evidence of a common ancestor

11. Vestigial Organs
A structure in an organism that has lost all or most of its original function over the course of evolution.
Provides evidence of changes in a species over time

13. Comparative Embryology
The study of similarities and differences in the early development of plants and animals
Similarities (like tails and gill slits of vertebrates) provides evidence of a common ancestor

14. Similarities in Early Development

15. Similarities in DNA
Species that are closely related have very similar sequences in DNA
Provides evidence of a common ancestor

16. So we have the evidence, we know species adapt, we know nature selects those that are most fit to survive, but how does a species change?
One mutation at a time!

17. A mutation is a change in the DNA base sequence of a gene.

18. Changes in DNA may change an organism’s physical appearance.

19. Mutations Harmful mutations hurt the success of the individual.
Provide an example of a harmful mutation.
Beneficial mutations help the success of the individual
Provide an example of a beneficial mutation.
Neutral mutations do not help or harm the success of the individual.
Provide an example of a neutral mutation.

20. Speed of Evolution
Gradualism- evolution happens gradually over many generations and long periods of time
What types of events or circumstances do you think would make gradual changes in a species?

21. Speed of Evolution
Punctuated Equilibrium- evolution that happens quickly over just a few generations
What types of events or circumstances do you think would make quick changes in a species?

23. The End