1. Evolution

2. Evolution- the development of new organisms from pre-existing organisms over time.
Why does it happen?

3. Evolution- the development of new organisms form pre-existing organisms over time.
Why does it happen?
So that organisms can survive changing environments (food, shelter, reproduction).

4. Adaptation vs. Acclimatization
Adaptation – Change in a population over time.
Example – whales loosing walking limbs
Acclimatization – Change in an individual in its lifetime.
Example: 40° in the Fall and 40° in the Spring

5. Best Supported Argument: Evolution!
“Thanks so Much! I would just like to thank a few people that made it possible for my explanation…”

6. Georges Cuvier Charles Lyell Observed changes in fossil layers of rock
Surmised that layers were different due to catastrophes (floods, ice ages)
CATASTROPHISM
Charles Lyell
Geologic processes that shaped the Earth’s surface in the past are still at work today.
“we find no vestige of a beginning, no prospect of an end.” - Hutton
UNIFORMITARIANISM

7. Lamarck: Inheritance of Acquired Traits

8. Use and Disuse
Body parts used to get along in the environment get stronger and larger
Those that aren’t used, deteriorate.

9. Inheritance of Acquired Characteristics
Modifications acquired during an organism’s lifetime could be passed on to their offspring.
Example: A weightlifter’s child could be born with a more muscular anatomy.

10. Charles Darwin
Developed the Theory of Evolution by means of Natural Selection and Descent with Modification

11. What is a Scientific theory?
Everyday vs. Scientific Theories
Everyday – an opinion
“My theory is that gas prices are going up because the gas stations are trying to make more money.”
Scientific - An extensively tested, well supported explanation.
“The theory of evolution states that over loooong periods of time, organisms change to fit their environment.”

12. Development of Theory of Natural Selection
Darwin observed 12 species of finches
Noted differences in beaks and how that correlated to food choice

13. Natural Selection
Some individuals are better adapted to their environment.
These individuals survive and reproduce (pass on their genes)

15. Descent with Modification
Supposed that all organisms were related to an ancient ancestor

16. Tree of Life
Common Descent: All organisms on Earth descended from a common ancestor 4 billion years ago.

18. Tree of Life Diagram represented a system of natural history.
Ancestors at the bottom, descendants at the top.
What does this remind you of?

19. Family Pedigree

20. Common Ancestor
An organism that is a shared ancestor (relative) between two or more different species.

21. Cladogram/Phylogenetic Tree
A diagram showing the evolution of species, including common ancestors. A B C

22. Cladogram/Phylogenetic Tree
Where is the common ancestor between crocodiles and birds?
Where is the common ancestor among birds, reptiles, and mammals?
Where is the common ancestor among all of the organisms? A B C

23. Human Evolution

24. Four Main Parts of Evolution by Natural Selection:
1. Overproduction- a population produces more offspring than can survive.
2. Genetic Variation- within a population individuals have different traits.
3. Struggle to Survive- if there is no competition there is no impetus to change.
4. Differential Reproduction- if you are better adapted, you will live longer an reproduce more.

25. Overproduction
Sea Turtles Hatching

26. Genetic Variation The genes within a population contains differences.
Are you exactly the same as the person next to you?

27. Variation exists among members of a species.

28. Again. . . why does variety persist?

29. Allele Frequency
The proportion of gene copies of a given allele in a population.
A change in allele frequency results in small evolutionary changes (microevlolution)

30. Gene Pool
All of the genes of the reproductively active members of a population.

32. Out of the gene pool?

33. Struggle to Survive

34. Struggle to survive
Individuals must compete with each other for resources.
Food, water, mates, etc.
Male Caribou fight for the right to breed with a female Caribou.

36. Differential Reproduction
Only the individuals with the best adaptations to their environment will survive competition.
Only the survivors will be able to reproduce and pass on their genes.

37. Differential Reproduction
Moths who were darker were better adapted to live on sooty trees.

38. Differential Reproduction

40. What supports the Theory of Evolution?
1. Direct Observation
2. Fossil record
3. Homologous structures
4. genetic/and or biochemical similarities

41. Direct Observations
Evolution of drug resistant viruses and antibiotic resistant bacteria
Peppered moths during Industrial Revolution.

43. Fossil Record
Skeletons and other preserved remains that show the changes in species over time.
Superposition- Where the fossil is in the ground help us determine which are older and newer species.

44. Homologous Structures Forelimbs of mammals that are now used for a variety of purposes, such as flying in bats and swimming in whale, but were present and used in a common ancestor for walking.
Homologous Structures have the a similar form, but different functions.

46. Genetic similarities
All life forms use the same genetic language of DNA and RNA.
Example- Amino acid sequences coding for hemoglobin in primate species shows great similarities

49. Types of Natural Selection
Directional
Stabilizing
Disruptive

50. Directional Selection
Natural selection where the most extreme form of a trait is favored and becomes common.
Birds of paradise

52. Stabilizing Selection
Natural selection where the average form of the trait is favored and is more common.

53. Disruptive Selection
Natural selection where two extreme forms of a trait are selected.

54. Artificial Selection
It has led to offspring through successive generations that can be very different in appearance and behavior from their distant ancestors.
Organisms with certain traits are bred repeatedly until population has only that trait
Example- Dogs, Corn, Broccoli, Cows, etc.

55. Artificial Selection

56. These chickens cannot stand or move.

57. Cow selectively bred for extra meat (muscle)
Cow selectively bred for extra meat (muscle). Usually cannot stand for more than a few minutes or walk more than a few steps.

58. Artificial Selection