Evolution

1
Evolution

• Natural Selection and Evidence
• Ch. 15.1

2
Definition

• Evolution the change in populations over time

3
Evidence

• How do we know that evolution happened?
• Adaptations
• Fossils
• Anatomy
• Embryology
• Biochemistry

4
Evidence

• Fossils
• Show changes through time
• Not complete, but gives the overall picture

5
Evidence

• Anatomy
• Homologous structures
• Similarity in form of major body parts
• Indicates that the species had a common ancestor

6
Evidence

• Homologous structures
• See p. 409 in book

7
Evidence

• Vestigial structures
• Body structure that has no function
• Probably was useful in an ancestor
• Ex. Appendix in humans, wings in ostrich, leg
  bones in snakes

8
Evidence

• Embryology
• Study of the earliest stages of growth
• Can see similarities in embryos that you dont
  see in adult forms
• Suggests they evolved from a common ancestor

9
Evidence

• Embryology

10
Evidence

• Embryology

11
Evidence

• Embryology

12
Evidence

• Embryology

13
Evidence

• Biochemistry
• All living things share same biochemistry
• Closely related organisms have more similar DNA
  sequences
• Can use comparisons of DNA to determine
  relationships between species

14
Evidence

• Can see it happening in species with short
  generation times
• Bacteria
• Insects
• Yeast