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

2. Evidence for evolution in Darwin’s time came from several sources.
Fossils
Geography
Embryology
Molecular Biology
Anatomy

3. Fossils
Fossils – preserved remains or markings left by organisms that lived in the past
Fossils provide evidence of evolution.
Fossils in older layers are more primitive than those in the upper layers.

4. Fossils
Fossil record – the chronological collection of life’s remains in sedimentary rock layers.

5. Transitional forms are links between modern animals and ancient.
Mesonychilds are the
hypothesized link
between modern
whales and hoofed
mammals.

6. Geography
The study of geography provides evidence of evolution.
Island species closely resemble nearest mainland species
Populations show variation from one island to another
Different plants, climates, and predators favored different traits in the population

7. Embryology provides evidence of evolution.
Identical larvae, different adult body forms
Similar embryos, diverse organisms
Larva
Adult barnacle
Adult crab

8. Embryology
Embryology provides evidence of evolution.
Embryos of fish, birds, reptiles, and mammals are all similar
They all have gill slits which develop into gills in adult fish and ears and throat in mammals
Molecular Biology
DNA and protein sequences are similar between related organisms

9. Anatomy
The study of anatomy provides evidence of evolution.
Homologous structures are similar in structure but different in function.
Homologous structures are evidence of a common ancestor.

10. The study of anatomy provides evidence of evolution.
Analogous structures have a similar function.
Analogous structures are not evidence of a common ancestor.
These species evolved separately
They faced similar environmental challenges and developed similar solutions
Human hand
Bat wing
Mole foot
Fly wing

11. Vestigial structures are remnants of organs or structures that had a function in an early ancestor.
Ostrich wings are examples of vestigial structures.
Examples in humans- appendix and coccyx (tail bone)