1. Evolutionary Evidence
Chapter 1.3

2. Theory
A widely accepted statement based on scientific evidence that help explain a group of facts.
Theories can change if new evidence is found.

3. Three different types of evidence provide a bigger picture of evolution
fossil
genetic
biological

4. Ancestor
An early form of an organism from which later form descended.

5. Fossil
Show that organisms that lived in the past are similar to species living today.
Two species with a common ancestor can develop differently in different locations.

6. Biological: Similarities in Structure
Vestigial Structures
Organs that were fully functional in an ancestral group, but are unused in later species.
Whales and snakes have small leg bones
Similar structures with different functions.
Indicates common ancestor.
Page 31

7. Biological: Similarities In development
The study of embryos shows that animals that appear to be very different as adults are similar during early development.
Page 32

8. Genetic
Scientists can tell how closely organisms are related by comparing DNA.
Compare human gene to a mouse gene.