Evolution

1. Evolution Textbook chapter 16

2. Such varied Honeycreepers • The misty rain forests on the Hawaiian island of Kauai is home to birds found nowhere else on earth • Why is there such a variation of honeycreepers?

3. Enter Chuck Darwin… • Born in 1809 • Sailed around the world in 1831 on the HMS Beagle • Noted similarities and differences among the finches (birds) and tortoises on Galapagos Islands with those in South America

4. Charles Darwin • Led Darwin to develop what has been called the “Best Idea Anyone’s Ever Had”—his theory of evolution • He hypothesized the animals adapted to local conditions on the islands after their arrival

5. Voyage of the Beagle • Darwin collected many specimens and observations while aboard the Beagle • Darwin came to 3 conclusions: • Species vary globally • Species vary locally • Species vary over time

6. Species Vary Globally • Darwin noticed that different, yet ecologically similar, animal species inhabited separate, but ecologically similar, habitats around the globe • EX. Rheas of South America vs. Ostriches of Africa vs. Emus of Australia

7. Species Vary Locally • Darwin noticed that different, yet related, animal species often occupied different habitats within a local area • EX. Tortoises on Isabela and Hood Islands within the Galapagos

8. Species Vary Over time • Darwin collected fossilsin addition to specimens • Darwin noticed that some fossils of extinct animals were similar to living species • EX. Armadillo vs Glyptodont

9. The Science of Darwin’s Day • Most European’s in the early 1800s believed Earth was only a few thousand years old, and that it hadn’t changed much since • By the mid 1800s, geology provided evidence about the history of Earth • James Hutton and Charles Lyell concluded that the Earth is extremely old and that the processes that changed Earth in the past and the same that operate in the present

10. Hutton & Lyell

11. Lamarck’s Evolutionary Hypotheses • Darwin wasn’t the first to suggest characteristics of a species could change over time, but the ideas on how the changed happened was different • Jean-Baptiste Lamarck suggested that organisms could change during their lifetime by selectively using or not using various parts of their bodies

12. Lamarck’s Evolutionary Hypotheses • He also suggested that these individuals could pass these acquired traits on to their offspring

13. Thomas Malthus • In 1798, Thomas Malthus noted that humans were being born faster than people were dying • Reasoned that if the human population grew unchecked, there wouldn’t be enough living space • Darwin realized that this idea applied more to other organisms than it did to humans

14. Darwin’s findings • Darwin published his book “The Origin of Species” in 1859

15. Natural Variation • Darwin argued that natural variation is found in all types of organisms • To explain this variation, he studied change produced by plant and animal breeders • The breeders would select breeding for only tree that produced the biggest fruit or cows that produced the most milk • Darwin called this artificial selection

16. The Struggle for Existence • Darwin realized that if more individuals are produced than can survive, members of a population must compete for food, living space, and necessities of life (Think Malthus)

17. Variation & Adaptation • Darwin hypothesized that some of the variations (adaptations) seen in a population make the organism better suited to life in their environment

18. Survival of the Fittest • According to Darwin, differences in adaptations affect an individuals fitness • Individuals with adaptations that are well suited to their environment can survive and reproduce have high fitness • The ability of individuals with favorable adaptations surviving and reproducing is what Darwin called “Survival of the Fittest”

19. Darwin’s 4 Postulates • Based on the patterns he observed, Darwin concluded that there were 4 parts (postulates) to the process of natural selection • Overpopulation • Variation • Struggle for Existence • Natural Selection

20. Clearly stated: What is the Evidence for Evolution? Video Worksheet • What are the two claims made by the theory of evolution? 1. All living things on earth are related 2. The evolution of living things is powered by a natural process • List 3 of the lines of evidence for evolution. 1. Comparative anatomy, embryology and development, fossil record 2. Species distribution, evolution observed, predictive process of evolution 3. Nested hierarchy of traits

21. 3. What branch included whales, dolphins, and porpoises? Cetaceans 4. Whales, dolphins, and porpoises evolved from what? 4 legged land mammals 5. What is comparative anatomy? The study of differences and similarities among living things

22. 6. List 3 ways whales are different from fish. 1. Have placentas, warm blooded 2. Give live birth, do not have gills 3. Feed milk to young 7. How many nasal passages do dolphins have? 2 8. What is located in a whale flipper? Arm, wrist, hand and finger bones 9. Do whales have leg bones? Yes

23. 10. What is embryology? The study of how creatures develop before being born or hatching from an egg 11. Both humans and whale embryos have arm buds and leg buds 12. How long ago did Basilosaurid live? 34-30 million years ago 13. Where is Basilosaurid’s nasal opening? In the middle of the skull

24. 14. List 2 ways we know Maiacetus was a whale? 1. Skeleton found among sea creature fossils 2. Short legs, long fingers and toes suggests a strong swimmer 15. Maiacetus is called a walkin whale 16. DNA contains chemical codes 17. Whales closest living DNA match is a hippopotamus

25. 18. About how long ago did the whale/hippo common ancestor live? 54 million years ago 19. Whales and hippos share what characterisitics? Special shaped ankle bones, give birth and nurse underwater Multi-chambered stomachs, missing coat of fur Have internal testes 20. Bird wings are modified arms and legs

26. History of Life

27. The Fossil Record • Paleontologists use fossils to infer what past life forms were like—the structure of the organisms, what they ate, what ate them, and the environment in which they lived

28. Sue the Dinosaur • Discovered in 1990 • Largest, best preserved, & most complete T. rex specimen • More than 90% complete • Auctioned in October 1997 for $7.6 million to the Field Museum • Highest ever paid for a dinosaur fossil

29. Fossil Record • The fossil record provides evidence about the history of life on earth • Also shows how different groups of organisms have changed over time

30. 17-2 Review • What substances probably made up Earth’s early atmosphere? • Hydrogen Cyanide, Carbon Dioxide, Carbon Monoxide, Nitrogen, Hydrogen Sulfide, & Water • According to the endosymbiotic theory, how might chloroplasts and mitochondria have originated? • Prokaryotes that performed photosynthesis & Prokaryotes that performed cellular respiration joined with anaerobic prokaryotes and remained there as organelles

31. Precambrian time • Almost 90% of Earth’s history occurred during Precambrian time • Anaerobic forms • Photosynthetic forms • Aerobic forms • Eukaryotes • Multicellular life forms

32. Paleozoic Era • Rich fossil evidence shows that early in the Paleozoic Era, there was a diversity of marine life • Broken down into: • Cambrian Period • Ordovician and Silurian Periods • Devonian Period • Carboniferous and Permian Periods

33. Cambrian Period • “Cambrian Explosion” • For the first time, many organisms had hard parts—Shells & outer skeletons • The first known representatives of most animal phyla evolved • Jellyfishes, worms, sponges, brachiopods, trilobites

34. Ordovician & Silurian Periods • Ancestors of many octopi & squids appeared • Many aquatic arthropods • Jawless fish • The first land plants evolved from aquatic ancestors

35. Devonian Period • Plants adapted to drier areas • Insects appeared on land • Often called “Age of Fishes”—most had jaws, bony skeletons, & scales • Vertebrates began to invade the land • Some of these early 4-legged organisms evolved into the first amphibians

36. Carboniferous & Permian Periods • Life expanded over Earth’s continents • Reptiles evolved from certain amphibians • Winged insects evolved • Giant ferns and other plants formed swampy forests

37. Permian Period • At the end of the Paleozoic many organisms died out • The mass extinction at the end of the Paleozoic affected both plants and animals on land and in the seas. • As much as 95% of the complex life from the oceans disappeared

38. Mesozoic era • Events during the Mesozoic include the increasing dominance of dinosaurs. • The Mesozoic is marked by the appearance of flowering plants • Broken into: • Triassic Period • Jurassic Period • Cretaceous Period

39. Triassic Period • Organisms that survived the Permian Period became the main forms of life early in the Triassic • Important organisms—fishes, insects, reptiles, cone-bearing plants • “Age of Reptiles” • ~225 million years ago—first dinosaurs appeared • Mammals first appeared (small—about the size of a mouse)

40. Jurassic Period • Dinosaurs became the Dominant animals on land • “Ruled” the Earth for about 150 million years • One of the first birds, Archaeopteryx, appeared

41. Cretaceous Period • Reptiles were still the dominant vertebrates • Dinos like the T. Rex controlled the land, while flying reptiles ruled the skies • New forms of life—leafy trees, shrubs, small flowering plants • At the end of the Cretaceous, another mass extinction—more than 50% of all plant and animal groups were wiped out

42. Cenozoic Era • During the Cenozoic, mammals evolved adaptations that allowed them to live in various environments—on land, in water, and even in the air • Broken into: • Tertiary Period • Quaternary Period

43. Tertiary Period • Earth’s climates were generally warm and mild • Whales and Dolphins evolved • Flowering Plants and insects flourished • Grasses evolved • Some mammals became very large

44. Quaternary Period • Earth’s climate cooled—causing a series of ice ages • Continental glaciers advanced and retreated over parts of Europe and North America • ~20,000 years ago Earth’s climate began to warm (causing glaciers to melt)

45. Quaternary Period • Algae, Coral, Mollusks, Fishes & Mammals thrived in oceans • Insects and Birds shared the skies • Mammals (bats, cats, dogs, cattle, mammoths) became common • Early human ancestors appeared about 4.5 million years ago • First Homo sapiens about 200,000 years about in Africa