Darwin and Evolution

1. “There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.” -Charles Darwin, On The Origin of Species, 1859

2. Darwin and Evolution

3. Do NOW! What happens when specific traits are passed down through many generations?

4. Charles Darwin • Born February 12, 1809 • Died on April 19, 1882

5. Darwin's Importance • Darwin’s father decided his son should study for the clergy at Cambridge - a very respectable profession in the early 1800's. • Beetle collecting during his time at Cambridge taught Darwin many vital scientific skills, which included: how to identify species, the proper manner of cataloguing specimens, methods of comparative anatomy, and how to work efficiently in the field.

6. Darwin's Importance • 1831-1836 sailed on H.M.S. Beagle - Originally the ship's geologist, eventually also naturalist (studied living things & environments)

7. The struggle for survival… • 1838 OctoberDarwin read a book by the famous economist, Revd. • Thomas Malthus, titled "Essay on the Principle of Population." • the economic theory that as human populations grow and resources become scarce the weak die off in a struggle for existence. • What Malthus saw in economics, Darwin saw in nature.

8. To publish or not to publish? • 1842Darwin made an outline of reasons not to published his transmutation ideas - [1] Fellow naturalists would never accept his ideas. [2] animal breeders would find a huge treatise too boring to read. [3] the trouble making atheists would use it for their evil agendas. [4] the church would scorn him. [5] he did not want to be labeled an atheist. [6] he would betray his friends and family

9. 1854 DecemberAt last Darwin figured out how populations split off into separate species. • Using the industrial revolution as a metaphor, he saw that populations of animals, like industry, expand and specialize to fit into niches with competition acting as the driving force. • He saw nature as the ultimate "factory.“

10. 1860 January The repercussions of Origin of Species were mixed. Thomas Huxley and Joseph Hooker thought very highly of it and soon became stronger allies with Darwin. Huxley soon became a ruthless defender of evolution, even going so far as to suggest that mankind was a transmuted ape!

11. Richard Owen was outraged by the Origin. He saw the ideas expressed in the book as being dangerous to society. Most readers, however, simply did not understand how natural selection worked. They could not see who or what was doing the selecting. Many assumed god was the selector.

12. Darwin wondered:Why were these animals different? Why would they have these obviously different characteristics if they were similar organisms?

13. Differences in Similar Organisms • Darwin observed similar organisms on mainland South America and the Galapagos Islands Examples: Cormorants: on the mainland, these could fly, but the species that lived on the islands was flightless

14. Tortoises: each island had a species of giant tortoise, but the shape of their shells varied on each island; Darwin could identify which island the tortoises came from just by looking at their shells.

15. Iguanas: on mainland they had small claws to climb trees and ate cactus & flowers while island iguanas could swim, had long claws to grip rocks and ate seaweed

16. Adaptations • These differences are called adaptations • In order to survive in different places, the original organism had to change • This change was not a choice, but through genetic diversity

17. Cormorants: no predators, everything they needed was close to the ground, therefore, they lost the ability to fly Loss of flight is an adaptation.

18. Warm UP: Darwin's Finches Finches on different islands have different beaks. Why???? Beak type depends on the food available. Finches that are adapted to eat the available food on their island will survive long enough to reproduce. This will pass the trait for the beak that is best suited for survival in that area.

19. Natural Selection the idea that animals that are better adapted for a particular environment will survive, reproduce and pass on these desirable attributes to the next generation

20. Darwin was not the first naturalist to think of evolution…

21. Jean-Baptiste Lamarck • Change through use and disuse • When environments changed, organisms had to change their behavior to survive. If they began to use an organ more than they had in the past, it would increase in its lifetime. Meanwhile organs that organisms stopped using would shrink.

22. If a giraffe stretched its neck for leaves, for example, a "nervous fluid" would flow into its neck and make it longer. Its offspring would inherit the longer neck, and continued stretching would make it longer still over several generations.

24. Natural Selection • overproduction-producing many more offspring than will survive

25. Natural Selection • competition- "fighting" for available resources (food, shelter, mates). Those that are not successful will die, those that are will reproduce.

26. Natural Selection • variation- differences among individuals in the same species or group.

27. Natural Selection • Differential survival and reproduction -Over generations the character of a population changes as the frequency (how often it is available) of a trait increases or decreases

28. Can you Spot the moths?

29. Adaptations work by mutations. If a mutation in an individual helps it to survive, it will survive and reproduce, passing the gene for the mutation on to its offspring. Species have three “choices”: Go extinct in that area. Move to another area (emigrate). Adapt to survive the stress.

30. Darwin wondered:So what is evolution anyway? What evidence suggests this process?

31. Evolution • Many generations of natural selection lead to permanent changes in a species. • This is called evolution and occurs gradually over time.

32. The central ideas of evolution • that life has a history—it has changed over time • that different species share common ancestors. • are represented in “family trees,” and affects biological classification.

33. The central ideas of evolution • Fitness • describes the ability to both survive and reproduce, • is equal to the average contribution to the gene pool of the next generation that is made by an average individual of the specified genotype or phenotype.

34. Coevolution • The term coevolution is used to describe cases where two (or more) species reciprocally affect each other’s evolution. • Coevolution is likely to happen when different species have close ecological interactions with one another. These ecological relationships include: • Predator/prey and parasite/host • Competitive species • Mutualistic species Example:

35. Convergent evolution • A kind of evolution wherein organisms evolve structures that have similar (analogous) structures or functions in spite of their evolutionary ancestors being very dissimilar or unrelated. Example:

36. Divergent evolution • The process of tracing back two or more species to their common ancestor that indicate how they have diversified and diverged. Example:

37. Adaptive radiation • The diversification of several new species from a recent ancestral source, each adapted to utilize or occupy a vacant niche Example:

38. WHAT TO DO: • Complete the packet using your notes from today’s information. • Using the data table from Friday. Calculate the total number of each color of “worm” collected. (I placed 23 of each color outside). Create a bar graph of how many of each were “captured”. • Figure the percent of color “captured”. • Which color had the highest percent of capture? Which one the least? Why? • How does this activity relate to natural selection and evolution? Which color would begin to increase it’s population size? Why?

39. WARM UP: • What are the four types of evolution? • What are the central ideas of evolution?

40. Evidence of Evolution: Fossils Fossil records of past creatures & plants...we can examine them and compare them to organisms living today to look for similarities Sloths- Darwin found fossil sloths in South America, but they were MUCH larger than the living specimens he saw in the jungles Sharks- aside from being smaller, sharks haven't changed much in the last 100 million years...we know this from fossil evidence:)

41. Evidence for Evolution: Anatomy Analogous Structures • have the same function, but not the same structure. • The bird wing and insect wing are analogous structures.

42. Evidence for Evolution: Anatomy Examples: Homologous structures- structures that share similar bone arrangements and/or function in organisms that share ancestors

43. Evidence for Evolution: Anatomy • Vestigial structure: a body structure in a present-day organism that no longer serves it’s original purpose, but was probably useful to an ancestor

44. Evidence of Evolution: Biochemistry • Every organism has a specific DNA sequence • The more closely related organisms are the more similar their sequence is. • For example a human’s DNA sequence is more similar to a chimp’s than to a frog’s so we are more closely related to chimps than frogs.

45. Evidence for Evolution: Embryology

46. Phylogeny vs. Ontogeny • Phylogeny: the connections between all groups of organisms as understood by ancestor/descendant relationships • Ontogeny: a purely biological unfolding of events involved in an organism changing gradually from a simple to a more complex level

47. Two major hypothesis on how evolution takes place • Gradualism: the slow and constant change of an organism

48. Two major hypothesis on how evolution takes place • Punctuated equilibrium: species evolved rapidly, then stayed the same for longer periods of time

49. Activity: Examining the Fossil Record • Follow the directions in the packet. • Answer the analysis questions.

50. Natural Selection Evolution Warm Up! Explain the diagram above… what does it mean? New Species