1. Chapter 16 Darwin’s Theory of Evolution

3. Game
If you got lost on an island who would you rather be stuck on the island with?
The island is completely remote and you will be the only two on the island.
Goal is to survive!
Pbs.org evolution

4. Left or Right?
Bear Grylls

5. Left or Right?

6. Left or Right?

7. Left or Right?
Your mom or dad?

12. If you are on fire, what do you do?

13. Is this evolution?

14. 16.1 Darwin’s Voyage of Discovery
What is evolution?
Change over time.

15. Story
In 1831, a young man at 22 years old volunteered to set sail on a voyage to visit different countries.
The ship was meant to charter the South American coastline for the British navy.
This man did not want to fight or be in the navy.
He wanted to observe nature.
Who am I talking about?
Charles Darwin

16. Darwin’s observations
Large # of species
Organisms are well adapted to their environments
Organisms do not necessarily appear in same ecosystems / locations
Collected fossils
Galapagos Islands
Each island had different climate and vegetation
Observed different but similar species on the different islands
EX: tortoises, finches, marine iguanas

17. Depending on the location, Darwin noticed variations in tortoises and finches.
Some tortoises had long necks (eat tall shrubs) while other had short necks ( eat food off the ground).
Some finches had long beaks ( eat bugs), while others had short beaks (eat nuts).

18. Giant Tortoises of the Galapagos
Pinta Island
Hood Island
Isabela Island

19. Darwin’s Finches

20. In 1844 after doing further research and support from other scientists, Darwin wrote a 200 page essay that outlined his ideas, but did not release it to public.
After gathering more research in 1859 he released his book The Origin of Species.
Why did Darwin wait so long to release his book?
Didn’t want to slander his fathers name, going against the church.

21. Darwin’s Patterns of Biodiversity
1. Species vary globally
2. Species vary locally
3. Species vary over time

22. Species Vary Globally
Darwin noticed that different, yet ecologically similar, animal species inhabited separated, but ecologically similar, habitats around the globe.

23. Species Vary Locally
Darwin noticed that different, yet related, animal species often occupied different habitats within a local area.
Which specie of turtle will survive?

24. Species Vary Over Time
Darwin noticed that some fossils of extinct animals were similar to living species.
Fossils:
Preserved remains or traces of ancient organisms.

28. 16.2 Ideas That Shaped Darwin’s Thinking
There were two theories about life before Darwin.
1. Species were all fixed, or permanent. (Creationism)
2. The Earth is only 10,000 years old and still not changing.
Which do you agree with, are they correct?

29. Hutton and Lyell
Hutton and Lyell concluded that the Earth is extremely old and that the processes that changed Earth in the past are the same processes that operate in the present.
Proved that Earth is old by understanding geology and the rock layers.

30. True or False
Kangaroos powerful hind legs were the result of ancestors strengthening their legs by jumping and then passing the acquired leg strength to their offspring.
False
Giraffes physically stretched their necks to be able to reach tall trees for food.

31. Jean Baptiste Lamarck
In the 1800s, Jean Baptiste Lamarck proposed that life evolves.
He thought that by using certain body parts, organisms develop certain characteristics, and these characteristics would be passed to offspring.
Lamarck’s principles were incorrect.

32. Thomas Malthus
Malthus noted that humans were being born faster than people were dying, causing overcrowding.
Believed that if the human population grew unchecked, there wouldn’t be enough living space and food for everyone.

33. Artificial selection:
Selective breeding of plants animals to promote the occurrence of desirable traits in offspring.
Farmers would select and breed the trees that produce the largest fruits or cows the produce the most milk

34. 16.3 Darwin Presents His Case
In order for natural selection to occur, these three things have to happen.
1. The Struggle for Existence
2. Variation and Adaptation
3. Survival of the Fittest

35. Darwin’s Idea of Natural Selection
All species tend to produce excessive numbers of offspring, called overproduction.
As we produce more offspring, resources become limited.
This leads to a struggle of existence.
The best adapted organisms will survive and reproduce. This is called survival of the fittest.
What makes organisms different is called variation.

36. What does it mean to be fit?
Fitness:
How an organism can survive and reproduce.

37. If you are the biggest, strongest animal in your specie, are you always going to be fit?
Remember even if the biggest, strongest, lion in the jungle has zero fitness if it is sterile.

38. What is natural selection?
Process by which organisms with variations most suited to their local environment survive and leave more offspring.

39. Natural Selection Giraffes

40. Natural Selection College

41. Common Descent
Darwin believed that all animals came from a common ancestor.
All species, living and extinct, are descended from a common ancestor.

42. 16.4 Evidence of Evolution What are some evidence for evolution?
Fossil Record
Geographic Distribution
Similarities in Structure
Similarities in Development
Molecular Biology

43. Biogeography:
Study of where organisms live now and where they and their ancestors lived in the past.

44. FOSSIL RECORD Modern Whale Transitional Forms Common Ancestor
If evolution is slow and steady, we'd expect to see the entire transition, from ancestor to descendent, displayed as transitional forms over a long period of time in the fossil record
Common Ancestor

45. Comparing Anatomy and Embryology
Homologous structures:
Similar structures in species sharing a common ancestor, but with different function.

46. Comparing Anatomy and Embryology
Analogous structures:
Different structure but similar function.

47. Comparing Anatomy and Embryology
Vestigial structure:
Remnants of important structures from ancestral species, but serve no current function.

48. Similarities in Development
Many embryos of vertebrates look very similar during certain stages of development.

49. (At Left): For examples of the early stages of development in vertebrate embryos. Unlike Haeckel's drawings, these photographs are absolutely accurate and have been taken at similar stages of development.
Top: a Fish Embryo Next: a Chick Embryo Next: a Pig Embryo Bottom: a Human Embryo
All of these photomicrographs were taken by the Swedish biophotographer Lennart Nillson, and can be viewed directly at the Odyssey of Life website (part of the NOVA science series on Public Broadcasting)

50. Which is more closely related?

51. Molecular Biology
DNA/Protein in closely related species are more similar.
Humans /chimps – Only 1 amino acid difference (Closely related)
Humans /dogs – 11 amino acid differences
Humans /rattlesnakes – Approx. 20 amino acid differences (Distant relatives)

52. What are some abiotic things that have gone extinct? Why?