1. EVIDENCE FOR EVOLUTION

2. WHAT IS EVOLUTION? To evolve: to change
A theory stating that all life has changed from simpler life to more complex life
Occurs over LONG periods of time
Evolution often supports that organisms have evolved from a common ancestor

3. FOSSIL EVIDENCE Fossils: remains of organisms that lived in the past
Footprints/bones/teeth/preserved organisms
Tell us about climate of the past
Tell us about what organism ate
Indicate change (see what organism looked like then compared to now; see organisms that lived in past but no longer exist today

4. Older fossils will be deeper in sediment
Layers are deposited over time on top of the older layer
Fossils show that organisms have evolved from SIMPLER organisms (bacteria, invertebrates) in the lower layers to more COMPLEX organisms (vertebrates: fish… reptiles…mammals) in the upper layers
EX: a magnolia (flowering plant)would be younger than a fern
A squid (invert) would be older than a lizard (reptile)

5. EVIDENCE FROM FOSSILS How has the horse changed over time?
How would studying the fossil evidence of the horse support the theory of evolution?
The fossil evidence shows that the horse has changed over time in height, teeth structure,and bone structure

6. What would this fern fossil tell us about climate?
This fossil was found in Antarctica.
How could Antarctica have the type of climate suggested by this fossil evidence?
Antarctica must have been a warmer climate; ferns are tropical plants
If it had been closer to Equator;
Pangaea

7. These two crocodiles were found on different continents

8. STRUCTURAL EVIDENCE

9. HOMOLOGOUS STRUCTURES
Similar in structure; not necessarily similar in function
Suggests common ancestry

10. The structures illustrated above are called HOMOLGOUS Structures
The structures illustrated above are called HOMOLGOUS Structures. Each limb has a similar STRUCTURE, but some of the limbs have different FUNCTION. The similarity of structure is evidence that the animals may have A COMMON ANCESTOR

11. ANALOGOUS STRUCTURES Similar in structure & function;
Not similar in ancestry
Organisms adapt to similar environments;
Therefore, they develop similar characteristics

12. EXAMPLES HOMOLGOUS ANALOGOUS Leg of dog Arm of human Wing of bird
Flipper of whale
All have similar bone structure, but the function is different (leg: walking; arm: carrying; wing: flying; flipper: swimming)
Wing of bird
Wing of bat
Leg of lizard
Leg of cow
These structures are similar in bone structure & function, but are unrelated species…different ancestors

13. VESTIGIAL STRUCTURES Structures present, but have no purpose
Structures that are incomplete
The presence of these structures indicates the structure once had a purpose (support for evolution)
EX: leg bones in whales, snakes

14. Vestigial Structures in Humans

15. EMBRYONIC EVIDENCE EMBRYO: early stage of development of living things
Many organisms look similar very early in their development
More stages similar… the more closely related they are
Suggests common ancestry (note how similar these different organisms are in early stages)

16. BIOCHEMICAL EVIDENCE
BIOCHEMICAL SIMILARITIES OF ORGANISMS
Comparison of Organisms
% substitutions of amino acids in Cytochrome C
Two orders of mammals
5-10 %
Birds vs. mammals
8-12 %
Amphibians vs. birds
14-18 %
Fish vs. Land vertebrates
18-22 %
Insects vs. vertebrates
Algae vs. animals
57 %
BIOCHEMICAL evidence is referring to similarities in DNA, proteins, amino acids, enzymes, etc.
The more similar these compounds are in different organisms, the more closely related they are
Suggests common ancestry

17. We are most similar/ most closely related to chimp
least similar/ closely related to chicken
Hedgehog is most similar to mouse… based on the closeness of the DNA similarities…3% difference