1. How Scientists Determined that Living Things Change Over Time
4/6/2017
Evidence of Evolution
How Scientists Determined that Living Things Change Over Time
Video #3 – “How Do We Know Evolution Happens?”
Printed off Blackboard

2. Fossil Record Fossil = remains of any living things or their prints
Fossils include:
Bones
Casts or molds
Impressions
Top left – impression of a worm; center – cast of a mollusk; right – humerus bone of a turtle
“Becoming a Fossil” – 2:34

3. Comparative Anatomy- body parts
Comparing the structures of organisms
Similarities indicate evolutionary relationships.

4. Comparative Anatomy, cont’d
Homologous structures – have similar insides
these have a similar structures and may or may not have a similar function
indicate common ancestry:

5. Comparative Anatomy, cont’d
Analagous structures – have similar outsides
these have a different structure but similar function
indicate common environmental pressures:

6. Comparative Anatomy, cont’d
Vestigial structures – seem to have little or no importance in modern organisms
Indicates that the structures were useful (a long time ago)
The pelvis (and femur) of a whale is a vestigial structure;
it suggests that ancestors of whales had four legs
Humans also have vestigial structures
Tonsils & Appendix
Whale Evolution – 5:09

7. Comparative Embryology
Closely related organisms appear to go through similar stages as embryos
“Common Past, Different Paths” – 1:36

8. Comparative Biochemistry / Molecular Biology
There is a common genetic code DNA
Analyzing and comparing DNA sequences and proteins can show a relationship among species.
“The Common Genetic Code” – 4:20

9. The genetic similarities between humans and primates indicates that we share a common ancestor – NOT that humans came from apes!
Humans are more similar (genetically) to chimpanzees than to gorillas or orangutans. This suggests that humans and chimpanzees split / branched off from our common ancestor more recently than gorillas and orangutans.
“Human Chromosome 2” – 3:27