1. Evidence of Evolution

2. Bellwork
Explain the difference between a scientific theory and a hypothesis.
Give an example of a scientific theory and a hypothesis.

3. Objectives
Explain how the various disciplines of biology support the Theory of Evolution

4. Key Terminology All support Darwin’s idea of descent with modification
Biogeography
Fossil record
Comparative anatomy
Homologous structures
Vestigial Organs
Comparative embryology
Molecular Biology
All support Darwin’s idea of descent with modification

5. Evolution is a Scientific Theory not an Educated Guess
Definition of a Scientific Theory
A well-tested explanation that unifies a broad range of observations collected from hundreds of experiments

6. Criteria to be a scientific theory
More general than hypothesis
General explanation of important natural phenomena
Derived from inductive reasoning
make specific observations  draw generalizations
Supported by empirical data
Theory continually tested
If Data contradict the theory
Modify the theory to satisfy all the data

7. PROPERTY OF PIMA COUNTY JTED, 2010
Think-Pair-Share
Identify whether the following is a scientific theory or educated guess?
Hannah will wear a polka dotted bikini to the beach in July.
All living things are made of cells
Infectious diseases are caused by different microorganisms called germs
It will be 100°F in Tucson by May 15th.
3. Think-pair-share
teacher presents a question
teacher gives wait time for student to form answer
teacher instructs students to share their answer with a partner
teacher calls on non-volunteers to share with the class
PROPERTY OF PIMA COUNTY JTED, 2010 3

8. Biogeography Definition: Geographic distribution of species
Key observations
Species on islands more closely related to species on nearest mainland than a distant mainland
Example: Organisms found on the Galapagos Islands more closely related to organisms on the South American coastline than the African coastline
Conclusion: Modern species evolved from geographical regions nearby their current residence

9. Fossil Record Definition of a fossil
Preserved remains of once living organisms
Scientists who study fossils are paleontologists
Fossils created:
Organisms become buried in sediment
Calcium in bone and other hard tissue mineralize
Surrounding sediment hardens and forms rock

10. Process of fossilization a rare event- Why?
Animal/plant life decay or are eaten before fossilization can begin
Fossils occur in rocks inaccessible to scientists
Destroyed by erosion or other natural processes before collected
Result: We have fossils for only a fraction of Earth’s organisms

11. Fossil Record
Sufficient evidence from fossil record to show evolution over time
From fossil record shown:
Bacteria appeared on Earth 3.5 billion years ago
Plants/animals appeared 500 million years ago
Chronological appearance of vertebrates
Fish  amphibians  reptiles  birds  mammals

13. PROPERTY OF PIMA COUNTY JTED, 2010
Think-Pair-Share
Why is the fossil record considered
evidence of Evolution?
Why are the gaps in the fossil record
not a good argument against Evolution?
PROPERTY OF PIMA COUNTY JTED, 2010 3

14. Comparative Anatomy Homologous structures
Definition: similar bones with different functions
Ex. forelimb of vertebrates
Conclusion: Vertebrates evolved from a common ancestor .

15. Comparative Anatomy (cont)
Vestigial Structures
Structures that have no modern function but did have function in presumed ancestor
Example
Vampire bat
has molar teeth

16. Pelvic Bone in whales

17. Comparative Anatomy Embryology Conclusion: Vertebrates
similar early embryo anatomy in vertebrates
Conclusion: Vertebrates
descended from a common ancestor

18. PROPERTY OF PIMA COUNTY JTED, 2010
Think-Pair-Share
How do Homologous Structures, Vestigial Organs and Embryos support the idea that vertebrates descended from a common ancestor?
PROPERTY OF PIMA COUNTY JTED, 2010 3

19. Comparative Biochemistry
Examine evolution at a molecular level
Macromolecules often compared between different organisms include
DNA
RNA
Protein

20. Comparative Biochemistry
Number of mutations determines how closely related:
Close relative
sequence of nucleotides or amino acids similar
very few or no mutations
Diverged more recently
Distant relative
Sequence of nucleotides
or amino acids different
more mutations
Diverged long ago

21. Molecular Connections

22. 3 Minute Summary
The various disciplines of biology all support the Theory of Evolution. Why is this stronger than if only one discipline supported Evolution?