1. EVIDENCE THAT SUPPORTS EVOLUTION

2. Definition of Evolution
Evolution: Change in heritable traits of biological populations over successive generations.
“Descent with modification”

3. Phylogenetic Tree: A diagram that depicts the lines of evolutionary descent of different species, organisms, or genes from a common ancestor.

4. Pillar #1: The Fossil Record

5. What is a fossil? The remains or evidence of an organism
Fossilized bone, wood, shell, or dung
Casts, imprints, or molds
Amber or tar entrapments
Imprints of footprints or borings

6. Organism trapped in amber
Original Remains
Replacement
Organism trapped in amber
Recrystallization
Carbonization

7. Original Remains preserved by ice
Footprints are Trace Fossils

8. Fossil Facts Most are found in sedimentary rock.
The fossil record shows that life has changed over time.
The fossil record is very incomplete.
Fossils give us a glimpse into the morphology of organisms now extinct.
Show Whale Video Clip and Do Whale exercise

9. Interpreting Fossil Evidence
Relative Dating – the age of a fossil is estimated by comparing it to other fossils in rock layers
Rock layers form in order of age – the oldest layers are on the bottom

13. Interpreting Fossil Evidence
Radioactive Dating – using radioactive decay to assign absolute ages to fossils
A half-life is the length of time required for ½ of the radioactive atoms in a sample to decay

17. Step 2: What do you want to solve? Underline the question.
If 100 g of Carbon-14 decays until only 25 g of carbon is left after 11, 460 years, what is the half-life of carbon-14?
Step 1: Pull out what you know from reading:
Step 2: What do you want to solve? Underline the question.
Step 3: Solve

18. Thallium-208 has a half-life of 3. 053 minutes
Thallium-208 has a half-life of minutes. How long will it take for 120 g to decay to 7.5 g?
Step 1: Pull out what you know from reading:
Step 2: What do you want to solve? Underline the question.
Step 3: Solve

19. Step 2: What do you want to solve? Underline the question.
Gold-198 has a half-life of 2.7 days. How much of a 96g sample will be left after 8.1 days?
Step 1: Pull out what you know from reading:
Step 2: What do you want to solve? Underline the question.
Step 3: Solve

20. Archaeopteryx (late Jurassic- 150 MYA)

21. Transitional Whale Fossils
~60 mya
~50 mya
~45 mya
~35-45 mya

22. Pillar #2: Structural Similarities Among Organisms

23. Homologous Structures
Structures that have similar characteristics but may or may not have similar functions.
Ex: forearms of vertebrates

24. Homologous : Similar structures, NOT similar functions

25. Vestigial Structures
Structures that are diminished in size and/or function.
Ex: eyes of moles
Ex: human appendix

26. Whale Vestigial Structure: Pelvis, Femur, leg bones.

27. Homologous & Vestigial structures give evidence of DIVERGENT EVOLUTION.
They suggest that descendants DIVERGED (became different) as the distance from the common ancestor increased.

28. Analogous Structures
Structures with the same function in organisms that are not closely related.
Ex: the wings of birds and the wings of insects.
Ex: thorns of the rosebush and the quills of the porcupine.

29. Analogous structures suggest CONVERGENT EVOLUTION.
Organisms did not descend from a common ancestor, they independently evolved similar adaptations to survive in similar environments.

30. Pillar #3: Biogeography The Geographic Distribution of Organisms

31. What is biogeography? The study of. . .
Where species live on earth and why
How organisms are adapted to their environment
Considers plate tectonics – shifting and movement of tectonic plates

36. Pillar 4: Embryological Similarities

37. Scientists study the
Biological development from time of conception (i.e. morphology of Embryo)
The fate of particular embryonic tissue

39. Pillar #5: Molecular Similarities

40. All organism have… The same “Genetic Code” 4 DNA nucleotides
Same 64 mRNA codons that code for the same amino acids
Ribosomes as the site of protein synthesis
ATP as the energy currency
Plasma membranes that consist of a phospholipid bilayer w/ imbedded proteins
Unity of composition suggests common descent

41. Compare common proteins
Count and compare how many of the amino acids differ
Compare the nucleotide sequences of DNA
the closer the DNA sequences, the more closely related the organisms are.
Show hemoglobin phylogenetic tree.

42. Molecular Comparisons

43. Pillar #6: Direct Observation

44. Examples of OBSERVED Natural Selection
Example 1: DDT Resistant Mosquitoes
Example 2: Antibiotic Resistant Drugs
Example 3: Darwin’s Finches

45. resistant to insecticide
Example 4: Insects
resistant to insecticide