1. Evidence for…

2. Four Types of Evidence A. Fossils B. Transitional Forms
C. Comparison of Organisms
D. Evolution Today

3. A. Fossils Types of Fossils: 1. Actual remains--wolly mammoth, shells
2. Petrification--organic substances replaced by minerals
3. Molds--”hollow” left after decay
4. Cast--filled in mold
5. Traces--footprints, scat, tools (often found in lava, sediments, ice)

4. B. Transitional Forms Intermediate stages between old & new forms
Ex: whales, birds/reptiles (Ex: archaeopterix), amphibians/fish
Evolution- How Do We Kn#1713B99

5. Comparison of Organisms--similar structures which give support for evolution
Homologous Structures-- structures that are biologically similar in different species, but have changed through time
Ex: fin, arm, wing, hand

10. C. Comparison of Organisms cont…
B. Vestigial Structures --structures that are inherited but are now unused (without function)
Ex: tail bone & ear muscles in humans, whale pelvis, hip & leg bones in a snake

11. C. Comparison of Organisms cont…
Embryo Comparisons
--Similar embryonic development
Ex: vertebrate embryos look very similar (all have gill pouches & tails)
YouTube - What Can Embr#1713AE9

12. Embryo Comparison Pictures

13. C. Comparison of Organisms cont…
DNA Comparison -all living organisms have DNA with the same 4 bases (A, T, C, G)
All have similar amino acids (only 20 different a.a.)
Chimps & humans have 98.6% DNA relatedness

14. C. Comparison of Organisms cont…
Selective Breeding -humans have bred dogs over hundreds of years to obtain new breeds; seedless oranges

15. D. Evolution Occurs Today
Evolution is happening today, as we speak!
Ex: antibiotic resistant bacteria, new strains of viruses (flu)

16. Key Concepts Can you define………..? Fossils
Vestigial and homologous structures
Embryo
Selective and artificial breeding
DNA Comparision