1. Natural Selection and Evidence to Support Evolution
ACADEMIC ninth grade science

2. Pace of Evolution GRADUALISM: Slow Even pace PUNCTUATED EQUILIBRIUM:
Quick bursts
Many periods of no change

3. Natural Selection Darwin’s Mechanism for Evolution
Overproduction
Inherited variation
Struggle to survive
Successful reproduction
Adaptation of the species

4. Overproduction Too many offspring produced
Many variations -Gene Pool: the total of all alleles (variations) in population
-What is the allele frequency for feather color for this gene pool?

5. 2. Inherited Variation Mutation and random mating make variations
-Mutation: Changes in DNA ****(Darwin was missing this) -Random mating: mixing genes in reproduction
Most birds are blue
Sometimes, one is born green
Sometimes, one is born blueish-green

6. 3. Struggle to Survive Organisms compete for resources (food, shelter, mates, etc.)
Those with better variations survive

7. The birds face the challenge of blending in to survive.

8. Only some will survive and have the opportunity to pass on their successful genes.
Ugh!, so full…
EEP!
Blue-green birds stand out more
Blue-green birds are eaten

9. 4. Successful Reproduction Successful traits are passed to offspring
-More organisms with the successful trait -Fewer organisms with the less successful trait(s)
How has the allele frequency changed in this population?
This is evolution!

10. 5. Adaptation of the Species Adaptation: process by which a species becomes better suited to its environment ?
Hee, hee…

11. Warm up…
1. Use the diagram and explain the process of natural selection.

12. WollyBooger…

13. Examples: Sickle cell Anemia Peppered Moth

15. Evidence to Support Evolution

16. 1. Fossils Any trace of a dead organism
Calcium in bones is replaced with harder elements
Soft tissues don’t often fossilize
Age determined by radiometric dating

17. Fossil Activity

18. 2. Transitional Forms Intermediates between old and new species
Ex: modern horse descended from dog-sized animal with multiple toes

19. 2. Transitional Forms

20. Transitional Forms Activity

21. 3. Homologous Structures
Structures with a common ancestry
Modified versions of structures from other organisms
Ex: bones in appendages

22. 3. Homologous Structures

23. Which is NOT homologous & Why?A
Human
Lizard
Octopus B
Bird
Whale
Grasshopper
Lizard
Human

24. 4. Vestigial Structures Structures with no present function
Remnants of the past;
Previously served a function
Ex: human appendix-may once have been used for digestion
Ex: whale’s pelvis-not needed for swimming, is needed for walking

25. 4. Vestigial Structures

26. Vestigial Structures Activity

27. 5. Comparative Anatomy Vertebrates have similar early stages
Differences accumulate as development continues
New development instructions are added to old instructions inherited from ancestors.

28. 5. Comparative Anatomy

29. Comparative Anatomy Activity

30. 5. DNA and Proteins DNA make an organism’s proteins
DNA sequence holds the evolutionary history
If species changes, their DNA changes
Closely related organisms share more similar DNA
Ex: humans and chimps share 98% DNA

31. 5. DNA and Proteins Human-Human=99.5% similar
Human-Chimpanzee=98% similar
Human-Cat=90% similar
Human-Cow=80% similar
Human-Mouse=75% similar
(90% analogous regions)
Human-Chicken=60% similar
Human-Fruit Fly=60% similar

32. DNA and Proteins Activity
Cytochrome C article???????

33. So…evolution can cause speciation
Speciation: formation of a new species as a result of natural selection

34. Madagascar & Speciation

35. Warm up…
1. Use the diagram and explain the process of speciation.