1. Evidence of Evolution
Chapter 6 Section 2

2. Does natural selection occur today?
YES!
Cockroaches in a building…

3. Interpreting the Evidence
Fossils
Patterns of early development
Similar body structures

4. Similarities in Early Development
Fossils
Organisms that lived in past were different from organisms alive today
Similarities in Early Development
How are these organisms similar?

5. Similarities in Body Structure
Scientists began to compare body structures of living species to look for clues about evolution
Body structure: how its bones are arranged
Fish, amphibians, reptiles, birds, and mammals all have similar structures….
VERTEBRATE

6. Homologous Structures
similar body structures that related species have inherited from a common ancestor

8. Inferring Species Relationships
Scientists are now able to use more than just fossils, embryos, and body structures to determine how species are related…
TODAY…
DNA
Protein Structure
Fossils
Early Development
Body Structures

9. Similarities in DNA
Recently, scientists have begun to compare the genes of different species
The more similar the DNA sequence, the more closely related the species are
elephants and elephant shrews…

10. Combining Evidence
Evidence from DNA and protein structure have confirmed conclusions
Dog
Wolf
Scientists do sometimes change their hypothesis about species relationships…

11. Branching Tree
A diagram that show how scientists think different groups of organisms are related

12. How Do New Species Form?
When a group of individuals remains isolated from the rest of its species long enough to evolve different traits
River, Volcano, Mountain Range