1. KEY CONCEPT Evidence of common ancestry among species comes from many sources.

2. NGSSS
SC.912.L.15.1* Explain how the scientific theory of evolution is supported by the fossil record, comparative anatomy, comparative embryology, biogeography, molecular biology, and observed evolutionary change. (HIGH)

3. Evidence for evolution in Darwin’s time came from several sources.
Fossils provide evidence of evolution.
Fossils in older layers are more primitive than those in the upper layers.

4. The study of geography provides evidence of evolution.
island species most closely resemble nearest mainland species
populations can show variation from one island to another

5. Embryology provides evidence of evolution.
identical larvae, different adult body forms
similar embryos, diverse organisms
Larva
Adult barnacle
Adult crab

6. Comparative embryology:
Similar embryo development in closely related species

7. Homologous structures are evidence of a common ancestor.
Homologous structures are similar in structure but different in function.
Homologous structures are evidence of a common ancestor.
Human hand
Bat wing
Mole foot

8. Homologous Structures:
The study of anatomy provides evidence of evolution.
Homologous Structures:
Same underlying structures, different functions, different environments & common ancestor
Bird Wing
Porpoise Flipper

9. Comparative Anatomy: Structural similarities link related species

10. The study of anatomy provides evidence of evolution.
Analogous structures have a similar function.
Human hand
Bat wing
Mole foot
Fly wing
Analogous structures are not evidence of a common ancestor.

11. Structural patterns are clues to the history of a species.
Vestigial structures are remnants of organs or structures that had a function in an early ancestor.
Ostrich wings are examples of vestigial structures.
For example, humans have a tailbone at the end of the spine that is of no apparent use. Some snakes have tiny pelvic bones and limb bones, and some cave-dwelling salamanders have eyes even though members of the species are completely blind. Such seemingly functionless parts are called vestigial organs or structures. Vestigial organs are often homologous to organs that are useful in other species. The vestigial tailbone in humans is homologous to the functional tail of other primates. Thus vestigial structures can be viewed as evidence for evolution: organisms having vestigial structures probably share a common ancestry with organisms in with organisms in which the homologous structure is functional.

12. Comparative Biochemistry
Similar DNA sequences=
Similar Gene segments of the DNA
Code for similar traits
In closely related species