Warm Up

1. Warm Up Complete the Karotyping worksheet from last class.

2. Changes Over Time SOL: BIO 8 a-e

3. Theory of Evolution • Science is made up of many ideas, theories, and laws. Many of these ideas have gone through many changes throughout the years. • Our job as life-long learners is to examine all the evidence concerning a particular topic. • Evolution is part of the Core Knowledge curriculum for Biology. • The origin of life is a sensitive subject for many people. There are many theories concerning the change in things over time. • You may hold a different view than what will be presented as part of the Core Knowledge curriculum. • Out goal is to explore the theory of evolution from a scientific standpoint, not to discount any other theories on the origin of life.

4. Charles Darwin The Father of Evolution

5. History • During Darwin’s Time(1809 - 1875) most people believed the Earth was only a few thousand years old. • They also believed that neither the planet nor it’s living species had changed over that thousand years • Darwin’s ideas were shocking and radical

6. HISTORY • Darwin was influenced by many explorers and great thinkers who were starting to challenge views about the world • Some new ideas that were influential to Darwin’s discoveries were: • Taxonomy of Carolus Linnaeus • Lyell’s “Principles of Geology”

7. Binomial System of Nomenclature Carolus Linnaeus (1707 – 1778) Believed in the “Fixity of Species” or that all species have remained unchanged throughout the history of the Earth.

8. Charles Lyell • Father of Geology • Suggested that layers of rock form slowly and are moved up by the forces beneath Earth • His theories suggested that the Earth is millions of years old.

9. Suggests that sedimentary rock is very old – therefore the species that are represented in this rock must also be old. • Most fossils are found in sedimentary rock. • Older fossils will be found below younger fossils.

10. Charles Lyell • How did his ideas influence Darwin? • If the Earth could change over time, might life change as well? • The changes (evolution) Darwin would later suggest would have been possible only if the Earth were extremely old

11. Knowledge Check Who was Linnaeus? Who was Lyell? If Lyell looked at fossils in a cross section of sediment, would the fossils more towards the surface be older or younger than those below? Why?

12. Charles Darwin At the age of 22, he joined a 5 year expedition aboard the HMS Beagle to map the coast of South America

13. The voyage of the Beagle

14. Darwin’s Voyage • Darwin explored and collected specimens whenever The Beagle landed ashore • He noticed the diversity of organisms as he traveled and noticed how animals and plants seemed remarkably suited for their environment

15. One stop that was important to the development of Darwin’s theories was the Galapagos Islands • These islands are just west of South America and were particularly interesting because although they are very close together, they have dramatically different climates • Because they were formed by volcanoes, they range from barely at sea level to 1500m above sea level

16. Darwin’s Observations Land Tortoises • Shell shape varied from one island to another • Hood Island Tortoise: Long neck and curved shell allows this tortoise to reach the high vegetation

17. Isabela Island Tortoise: Dome shaped shell and short neck as vegetation is closer to the ground

18. Through his observations made in the Galapagos Islands, Charles Darwin formulated a theory of how species change over time, called natural selection.

19. Charles Darwin’s Theory of Evolution by Natural Selection

20. 1. Heritable Variation: Members of a population have heritable variations.(Inheritance of traits)

21. 2. Overpopulation: In a population, more individuals are produced than the environment can support. They compete for food and shelter. (overpopulation- struggle for survival).

22. 3. Survival of the Fittest: Some individuals have adaptive characteristics that enable them to survive and reproduce better than other individuals (survival of the fittest). Fitness: Ability of an organism to survive and reproduce

23. 4. Adaptation: An increasing number of individuals in succeeding generations have these adaptive characteristics

24. Darwin described his theory in the form of a long essay which he called “On the Origin of Species”.

25. Concerned about the public’s response to his ideas(remember what happened to Galileo) Arranged to publish his work … AFTER HIS DEATH !!

26. He finally decided to publish his essay, “On The Origin of Species” in 1859

27. Charles Darwin At age 50 (1859) At age 65 (1874)

28. Charles Darwin Before publication After publication

29. Knowledge Check What was the name of Darwin’s book? On what islands did Darwin make observations that lead him to develop his ideas about natural selection? Explain how natural selection can be observed in a population.

30. How does Evolution work? • Evolution is governed by the principles of genetics • It is a change in successive generations of organisms, due to: • random mutation • Adaptation • Natural selection • Extinction

31. MUTATIONS • Genetic mutations and variety produced by sexual reproduction allow for diversity within a given population.

32. Mutations are inheritable changes because a mutation is a change in the DNA code

33. Mutation • Mutations are important in how populations change over time because they result in genetic changes to the gene pool.

34. A mutation may result in change that is: 1.Favorable; improves a species’ ability to exist in its environment

35. 2. Unfavorable; does not improve a species’ ability to exist in its environment.

36. 3. Neutral; neither harms nor helps the species.

37. Adaptation • Adaptations are structures, functions, or behaviors that enable a species to survive.

38. Adaptation • Depending on the rate of adaptation, the rate of reproduction, and the environmental factors present, structural adaptations may take millions of years to develop.

39. Natural Selection • the survival and reproduction of the individuals in a population that exhibit the traits that best enable them to survive in their environment. • The Survival of the Fittest

40. Natural Selection • Populations produce more offspring than the environment can support.

41. Natural Selection • This leads to competition for resources and individuals with certain genetic variations will be favored to survive and pass their variations on to the next generation.

42. These five canine species evolved from a common ancestor through natural selection Jackal African wilddog Wolf Coyote Fox Thousands tomillions of yearsof natural selection Ancestral canine

43. When humans choose organisms with specific characteristics as breeding stock, they are performing the role of the environment • This is called “artificial selection” Example of artificial selection in plants: five vegetables derived from wild mustard

44. Artificial Selection in Animals: Dog Breeding German shepherd Yorkshire terrier English springerspaniel Mini-dachshund Golden retriever Hundreds tothousands of yearsof breeding(artificial selection) Ancestral dog

45. Extinction • If a species does not include traits that enable it to survive in its environment or to survive changes in the environment, then the species may become extinct.

46. Individuals die, and eventually the species becomes extinct.

47. WARM UP • Explain how each process below can lead to evolutionary change. • Heritable Variation • Overpopulation • Survival of the Fittest • Adaptation

48. EVIDENCE FOR EVOLUTION

49. Darwin argued that living things have been evolving on earth for millions of years, and evidence could be found in: • the fossil record, • the geographical distribution of species • homologous structures of living organisms • Similarities in early development (embryology)

50. Fossil Record • Darwin saw fossils as a record of the history of life on Earth • By comparing fossils from older rock layers with fossils from younger layers, scientists could document the fact that life on Earth has changed over time.