1. Evolution and Natural Selection
How species change over time

2. Evolution and Natural Selection
Genetic variations are passed on through reproduction
Evidence for evolution illustrates how organisms are related
Natural selection leads to evolution
Our understanding of evolution has changed over time

3. Evolution
The theory that organisms today developed from more simple life forms and have changed (evolved) over time.

4. Natural Selection
The theory that states that those organisms best adapted to their environment have a better chance of surviving and reproducing.

5. What was Darwin’s hypothesis?
Darwin hypothesized that organisms had a common ancestor, but had adapted to their particular environments and changed over time.
Darwin published his
research in 1859

6. Natural Selection
For natural selection to occur, there must be at least two varieties of a species.
For example: the peppered moth

7. Peppered Moths
At the beginning of the Industrial Revolution in England, coal burning produced soot that covered the countryside in many areas

8. What do you think happened?

9. Evolution/Natural Selection
White moths became easier to see, while the black moths became harder to see. The black moths were more likely to survive and pass on the gene for dark color to their offspring.
Over time, the black moths
have become more common.

10. Evidence for Evolution: Common Ancestry
Common Ancestry: If species evolved from a common ancestor, then they should share common anatomical traits
Hawaiian Honeycreeper: family of
birds in Hawaii that have similar
skeletons and muscles, indicating
they are closely related.
Over time, their common ancestor evolved
into several species, each with a specialized bill for eating certain foods. Just like Darwin’s finches on the Galapagos!

13. Evidence for Evolution: Homologous Structures
If animals evolved from a common ancestor, then they should share common structures – and they do!
These are called
homologous structures

14. Evidence for Evolution Embryo Development
What do you notice? List 2 observations

15. Evidence for Evolution: Vestigial Organs
Some organisms have structures or organs that no longer have a useful function.
These structures or organs may have been useful to the ancestors of a species, but over time have evolved into what we term vestigial organs.

16. Examples of Vestigial Organs
Kiwi (flightless bird)
Whales (hind leg bones)
Humans (tailbone, appendix)

17. Evidence for Evolution Fossils
Fossils provide a look
into the past
Scientists can trace how
a species has evolved
by studying fossils

18. Wrap Up the Evidence Common Ancestry Homologous Structures
Vestigial Organs
Embryonic Development
Fossils

19. Natural Selection Rests on 4 Premises:
There is variation in the traits of individuals within a population

20. Natural Selection Rests on 4 Premises:
There is variation in the traits of individuals within a population

21. Natural Selection Rests on 4 Premises:
There is variation in the traits of individuals within a population

22. Natural Selection Rests on 4 Premises:
There is differential survival and reproduction, i.e., some individuals survive and reproduce, some don’t

23. Natural Selection Rests on 4 Premises:
There is differential survival and reproduction, i.e., some individuals survive and reproduce, some don’t

24. Natural Selection Rests on 4 Premises:
There is differential survival and reproduction, i.e., some individuals survive and reproduce, some don’t

25. Natural Selection Rests on 4 Premises:
There is differential survival and reproduction, i.e., some individuals survive and reproduce, some don’t

26. Natural Selection Rests on 4 Premises:
Traits have a genetic basis, or are inherited from parents

27. Natural Selection Rests on 4 Premises:
Traits have a genetic basis, or are inherited from parents

28. Natural Selection Rests on 4 Premises:
Advantageous traits, which allows organisms to have more offspring, will become more common in the population over time.

29. Examples of Natural Selection: The Evolution of The Polar Bear
Our story begins with the Polar Bear’s closest living relative – the Brown Bear

30. The Evolution of The Polar Bear
Around 300,000 years ago a small group of Brown Bears became reproductively isolated from the rest of the population

31. The Evolution of The Polar Bear
This small founding population of Brown Bears were able to survive and reproduce living in the Arctic Tundra. After MANY generations, a random genetic mutation occurred

32. The Evolution of The Polar Bear
Because of the genetic mutation, a litter of Brown Bears exhibited WHITE coloration

33. The Evolution of The Polar Bear
How do you think the white fur color affected these bears chances of surviving long enough to have cubs of their own?

34. REMEMBER: Natural Selection Rests on 4 Premises:
There is variation in the traits of individuals within a population

35. REMEMBER: Natural Selection Rests on 4 Premises:
There is differential survival and reproduction, i.e., some individuals survive and reproduce, some don’t

36. REMEMBER: Natural Selection Rests on 4 Premises:
There is differential survival and reproduction, i.e., some individuals survive and reproduce, some don’t X X X X

37. REMEMBER: Natural Selection Rests on 4 Premises:
Traits have a genetic basis, or are inherited from parents

38. REMEMBER: Natural Selection Rests on 4 Premises:
Advantageous traits, which allows organisms to have more offspring, will become more common in the population over time. X X X X

40. X X X X X

42. X X X X X

44. X X X X X

46. X X X X X

48. X X X X X

50. What Happened?

51. Through Reproductive Isolation and Natural Selection
Through Reproductive Isolation and Natural Selection One Species Evolved Into Another New Species By Adapting To Its New Environment

52. We see this trend again and again in the Animal Kingdom
We see this trend again and again in the Animal Kingdom Speciation by means of Reproductive Isolation & Natural Selection!

54. Discussion Topic
Echidna and Platypus belong in the animal kingdom and in the Phylum Mammalia, though both Echidna and Platypus have characteristics that can be categorized in the mammal, reptile or avian phylum. If you were the scientist to change the taxonomy, would you change their classification or keep it the same? Give evidence and logical response. 

56. Activity Go to the following website and answer the worksheet.
You will need to download Java to play this.