2. Welcome to the World of Evolution Evolution just means that a species changes over time.

3. Types of Evolution Geographic Evolution – gradual, continuous change in the physical earth over the last 4.5 billion years. Organic Evolution – the gradual, continuous change in living organisms over long periods of time. Evolution attempts to answer the question: “How did life begin and how has it changed into the millions of species living today?”

4. Theory of Evolution Theory: idea supported by scientific evidence over a long period of time. Evolution: Change in a species due to DNA mutation over a long time. Mutations: accumulate as time goes on until a new species is formed.

5. Scientist have collected evidence Six types of evidence: 1. Fossils 2. Comparative anatomy 3. Comparative embryology 4. Comparative Biochemistry 5. Plate Tectonics 6. Adaptations

6. 1. Fossil Evidence: Once living remains of organisms But its Limited: Incomplete record Easily disrupted (erosion) Not all organisms get fossilized.

7. Types of Fossils: 1.Preserved in Amber or Ice 2.Bones 3.Petrifaction 4.Imprints – most abundant kind of fossil.

8. Most fossils are found in sedimentary rock – formed when water flows over land, carrying the sediment (and whatever life form) into a body of water. Over time pressure turns the sediment into rock, preserving what’s inside.

9. Formation of Sedimentary Rock Water carries small rock particles to lakes and seas. Dead organisms are buried by layers of sediment, which forms new rock. The preserved remains may later be discovered and studied. Section 17-1 Go to Section:

10. 2. Comparative Anatomy: comparing body parts in different species. A. Homologous Body Structures – same bone structure but different functions. Example – wing of bird, flipper of whale, human hand. Why? Same ancestors that evolved in different environments.

11. A. Homologous Structures: bone structures are almost identical but used differently.

12. B. A nalogous Body Structures – same function but totally different structure. Example – wing of bat, wing of a butterfly.

13. B. Analogous Structures Different underlying structures because they have different ancestors. Same function because they evolved in similar environments (air)

14. Comparative Anatomy Structures: Analogous: 1.Different ancestors 2.“analogy”=like 3.Different underlying structures 4.Same Function 5.Evolved in Similar Environments Homologous: 1.Same ancestor 2.“homo”=same 3.Same underlying structures 4.Different Functions 5.Evolved in Different Environments

15. C. Vestigial Organs: organs or traces of organs that serve no purpose. Example – hip bone and leg bone in whale

16. Whale evolution

17. C. Vestigial Organs: traces of organs that we evolved away from needing. Example: human tailbone: no longer have tail. Human appendix: was used to digest raw meat

18. 3. Comparative embryology : Similar embryo development between species

19. Human Mouse

20. 4. Comparative Biochemistry Proteins of all living things are made from the same 20 amino acids. All organism have DNA made of the same four bases: GCAT Includes the same sugar-phosphate backbone. Similar Genes /DNA sequences (order of base pairs)

21. 5. Plate Tectonics continents were one large, single land mass called Pangea. explains closely related species on separated continents. Ex. Grizzly Bear and Panda Bear

24. 6. Adaptations: Traits that help them survive is a particular environment Example 1: Inuit people, who live in the extreme cold of the Arctic, have short, thick bodies that hold in heat

25. Masai people who live in the hot, dry lands of Africa have tall, lean bodies that release heat easily.

26. Example 2: Plant Adaptations Venus Fly Trap Captures animals to supplement what is missing from its environment. Acquires minerals needed for photosynthesis

27. Leaf Adaptations: Succulents: found in areas with little rain fall. Thick leaves Store water, to prevent drying out

28. Pine Needles Shed snow Less water loss Tolerate wind

29. Flower Adaptations: Fly pollination: Hair along petals Putrid smell Bee pollination: Smooth petal Sweet smell

30. Example 3: Bird Beak Adaptations

31. DESCENT WITH MODIFICATION: Each species has descended, with changes, from other species over time. All living organisms are related to one another. Similar DNA codes, Similar amino acid sequences, similar body parts and internal structures.

32. Actual tree of life is much more complex that even this. 99.9% of all species that have ever existed are extinct.

33. Common descent – all species – living and extinct – were derived from common ancestors. Humans did not evolve from apes. We have a common ancestor that was neither human nor ape.

34. Theories of Evolution: Lamarck Malthus Darwin

35. Jean-Baptiste Lamarck One of the first to try to describe why things change over time AKA evolution Two ideas 1.Use & Disuse 2.Inheritance of Acquired Traits Both are INCORRECT

36. 1.USE and Disuse – use of a body part would make it evolve, disuse (no use) would make it disappear. 2.Ex. USE – Birds use front limbs for flying - grows wings. Ex. DISUSE – If birds stopped using wings, – they would decrease in size and disappear over time. INCORRECT

37. Lamark said “ Use of structure results in evolution When a giraffe stretches its neck for this high leaves, it grows bigger from parent to offspring.

38. USE AND DISUSE

39. 2. INHERITANCE Of ACQUIRED TRAITS: Lamarck claimed that if a body part was altered then it would be passed on to the offspring. Ex. If you work out and gain muscle mass – your offspring will be just as big. Disproved by Weisman – he cut off the tails of mice and mated them. Babies born with tails.

40. Thomas Malthus’s talked about population This influenced Darwin big time. 1798 said that babies were being born faster than people were dying. The population explosion would lead to competition for food and space. Famine, war and disease are our only threats.

41. Malthus’s Contribution to Darwins: Populations grow to a maximum level Food and land become scarce leading to competition. Fit animals out- compete the less fit

42. Charles Darwin’s explanation: Natural Selection: “Survival of fit” 1.Fit: best traits for certain area 2.Fit out compete others food, space and mates 3.they reproduce and babies have same traits: best fit 4.Best adapted species survive 5.Less fit die: starve, predators, illness

43. How did he come up with natural selection? 1831 set sail on H.M.S. Beagle to voyage around the world. He made many observations, collected samples, and made many hypothesis's about changes in life over time = evolution His explanation is called NATURAL SELECTION.

44. VOYAGE OF THE BEAGLE 1831-1836 VOYAGE OF THE BEAGLE 1831-1836

45. DARWIN’S VOYAGE DARWIN’S VOYAGE In 1835 he landed in the Galapagos Islands. What he observed and recorded, along with the specimen he took, changed the world

46. WHAT DID DARWIN SEE? In the Galapagos Islands he noticed the diversity of life on Earth. Many, many different types of animals Some were similar to animals on the mainland of South America

47. PATTERN’S OF DIVERSITY Saw different species with similar traits. All of the islands were close together but were very different. Tropical, marine, jungles, and mountainous. Finches were in all of these places but each looked a little different.

48. Ground Finches have crushing beaks, They lived in environments with seed. Crushing beaks could easily break the shell seed.

49. The Warbler Finch has a probing beak. It good at digging into trees and catching insects They are a different species but similar

50. Darwin noticed similarities and differenced on other animals as well Tortoises Iguanas

51. Marine iguanas: long slender tails for swimming. Eat mostly food in the water and have to swim to catch it

52. Tree iguanas: short tails, climbing feet. Ate food in trees Each had traits best for their environment Tree iguana could not feed easily in the ocean Marine Iguana might struggle in the tree They are a different species but similar.

53. Darwin began to wonder if all the finches were part of the same species at one time The tortoises and iguanas too. And the environment must play some role.

54. His conclusion: animals have different traits such as the finch beaks because they adapted to a changing environment. They were at one time, part of the same species. They branched out to different environments and changed over time, as the environment changed. Those birds with well adapted beaks to a specific environment survived those without died.

55. IDEAS THAT SHAPED \ DARWIN’S THINKING During this time Darwin was seen as a radical for his views. Europeans thought that robins always looked as the do and never changed

56. DARWIN PRESENTS HIS CASE (not in notes) 1858 he received an essay from Alfred Russel Wallace (naturalist) He summarized what Darwin was doing for 25 years and was going to publish his own findings.

57. PUBLICATION OF ON THE ORIGIN OF SPECIES (not in notes) Darwin wanted to beat him and published his works (1859). He said evolution had been taking place for millions of years & continues. He proposed the theory of NATURAL SELECTION. Wasn’t received well by the nonscientific community.

58. Natural selection: The environment is always changing. It selects which traits will allow an organism to be successful and survive to pass on those traits. Those organisms with the most beneficial traits are the “most fit” to their environment Individuals with low levels of fitness = die Individuals with high levels of fitness = live

59. 5 parts of Natural Selection 1.Overproduction 2.Competition 3.Variations 4.Adaptations 5.Speciation

60. 1.Overproduction: more individuals are born than the environment can support Resources such as food, water, and space are limited. This leads to competition. Some species reproduce so fast, and would overpopulate the earth. Some must die.

61. 2. Competition: members of a species must compete for limited resources to live. A STRUGGLE FOR EXISTENCE Members of each species compete regularly for food, space, sunlight, mates etc Faster deer to escape predators. Animals hide using camouflage? Beak shaped for food.

62. 3. Variation: differences found in individuals of the same species. Example: finch beaks, insect colors Much variation is found in nature. Some variations make organisms better able to survive in their environments. Put those same organisms in another environment and they die They get out competed by other organism better adapted to that environment.

63. 4. Adaptation: because of the variations or differences, some organisms are better adapted to their environment. Ex: crushing beaks are good in areas with seeds, long slender tails are good in areas with water. Fitness – the ability of an individual to survive and reproduce in it’s environment due its traits Survival in nature – live long enough to pass genes on to offspring. Traits that make organisms successful are passed to the next generation

64. 5. Speciation: a new species is created when enough time has passed. over time, variations that make a species successful accumulate Eventually, the entire species is different than it was. the changes become so great, a new species is formed.

65. SUMMARY OF DARWIN’S THEORY Individual organisms differ from on another. Organisms produce more offspring than could survive. Members of each species must complete for limited resources. Organisms have different advantages in the struggle for existence. Individuals best suited for their environment survive. Species change over time. Species alive today have descended with modifications. All organisms have a common ancestor.

66. MODERN THEORY OF EVOLUTION – Darwin’s theory was correct, but he couldn’t explain “WHY” evolution was. He didn’t know about DNA

67. Where do variations come from? Variations - Differences in traits They come from mutations in DNA (genes) They are Random Must occur in sex cells to be passed on to future generations

68. POPULATION GENETICS Evolution happens to populations, not individuals. Population – organisms of the same species living together in a given region that can breed. As individuals reproduce and die, the genetic makeup of the population changes. As the genes of a population changes from generation to generation, the population EVOLVES.

69. Sources of Variation in a population 1.Mutations: mutations are the reason for genetic change and therefore evolution. Darwin did not know about DNA 2.Sexual reproduction: new combinations of DNA bring about new traits. 3.Migration: individuals moving in & out of a population.

70. What is a species? To be part of the same species, organisms must: Show similar characteristics Successfully interbreed Producing fertile offspring Donkey + Horse= Mule (infertile)

71. Geography and Speciation Speciation: creation of a new species. It can occur naturally over a long period of time. Each species is found in a certain range. In different parts of the range, characteristics of the species can vary. The organisms must be able to adapt to the particular conditions in which they live. Differences may include: body size, coloration, behaviors.

72. How long does evolution take? 2 theories: 1.Gradualism 2.Punctuated equilibrium

73. 1. Gradualism Small gradual changes over a long period of time

74. gradualism

75. 2. Punctuated Equilibrium Large changes that happen rapidly Followed by long periods of no change

76. Punctuated equilibrium

77. Graphs showing time frame of Evolution: Gradualism: Punctuated Equilibrium Time #SPECIES#SPECIES #SPECIES#SPECIES

80. Adaptive Radiation: the process by which species evolve into a # of different species, each occupying a different niche or living area. “radiation”= branching from one source “adaptive”= traits which promote survival

81. One species branches out to different environments and over many generations, each changes in its own way. Each eventually becoming its own unique species. (they will be different species, but share traits in common). Example – Darwin’s finches

82. Common Ancestor: all living organisms have a common ancestor and all life can be traced back to one original cell. Common ancestor mean that living things can be traced back to a common relative. Example: Humans did not evolve from Apes but had a common ancestor with them 5 to 8 million years ago.

83. This organism was neither human nor ape. In its attempt to survive, this common ancestor branch out (adaptive radiation/divergent evolution. It ended up in different places where one group evolved into a human and another an ape Descent with modificationDescent with modification: organisms are modified and vary from their decedents.

84. Common ancestry

85. Make a list of adaptations that make these animals successful in their environments. Snow leopard cheetah

87. Adaptations of the Snow Leopard STRONG LEGS: jump long distances. BIG PADS ON FEET To help travel on the rocky surfaces and not sink into the snow. GREY, WHITE, SPOTTED FUR Camouflage to sneak up on prey. DOUBLE-LAYERED COAT Insulated warmth from the cold climate. LONG TAIL: balanced on top of the mountains. COMPACT BODY To keep insulated from the cold. BIG LUNGS To breathe in the high altitudes of the Himilayas.