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EVOLUTION

EVOLUTION. Chapters 15, 16, and 17. 15.1 The Puzzle of Life ’ s Diversity. I. Evolutionary Theory A. Evolution – a change (in a kind of organism) over time; a process by which modern organisms have descended from ancient organisms. 15.1 The Puzzle of Life ’ s Diversity.

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EVOLUTION

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  1. EVOLUTION Chapters 15, 16, and 17

  2. 15.1 The Puzzle of Life’s Diversity I. Evolutionary Theory A. Evolution – a change (in a kind of organism) over time; a process by which modern organisms have descended from ancient organisms.

  3. 15.1 The Puzzle of Life’s Diversity B. Theory – a well-supported testable explanation of phenomena that have occurred in the natural world.

  4. 15.1 The Puzzle of Life’s Diversity C. Darwin’s voyage of the Beagle 1. Darwin made numerous observations and collected evidence that led him to propose a revolutionary hypothesis about the way life changes over time. 2. That hypothesis has become the theory of evolution.

  5. 15.1 The Puzzle of Life’s Diversity II. Darwin’s Observations A. Patterns of Diversity 1. Darwin observed that plants and animals seemed to be well suited to their environment. 2. He observed the different way organisms survive and reproduce. 3. He also observed how similar ecosystems on different continents had different species rather than similar species.

  6. 15.1 The Puzzle of Life’s Diversity B. Living Organisms and Fossils 1. fossils – preserved remains of ancient organisms. 2. Darwin collected living organism and fossils. 3. Darwin observed how some fossils look similar to organisms still alive and others looked like nothing he had ever seen.

  7. 15.1 The Puzzle of Life’s Diversity C. The Galapagos Islands 1. The Galapagos Islands influenced Darwin’s studies the most. 2. The climate of each Island differed even though they are close together. 3. Darwin noted that the land tortoises and marine iguanas varied in predictable ways from island to island. Ex. The shape of the tortoise’s shell.

  8. Giant Tortoises of the Galápagos Islands Pinta Tower Marchena Pinta IslandIntermediate shell Hood Island Saddle-backed shell James Fernandina Santa Cruz Isabela Santa Fe Floreana Hood Isabela Island Dome-shaped shell

  9. 15.1 The Puzzle of Life’s Diversity III. The Journey Home A. On the journey home, Darwin studied the animals he collected and his findings. B. He noticed that mockingbirds collected from different islands looked different from each other.

  10. 15.1 The Puzzle of Life’s Diversity C. Darwin’s observed that the characteristics of many animals and plants varied noticeably among the different islands of the Galapagos. 1. He wondered if animals on different islands had once been members of the same species.

  11. 15.1 The Puzzle of Life’s Diversity 2. He concluded that these separate species would have evolved from the original South American species after becoming isolated from one another.

  12.  Darwin’s Voyage

  13. 15.2 Ideas that Shaped Darwin’s Thinking I. Lamark’s Evolution Hypotheses A. Lamark was one of the first scientists to recognize that living things change over time, all species were descended from other species, and organisms are adapted to their environment.

  14. 15.2 Ideas that Shaped Darwin’s Thinking B. Lamark’s hypothesis – that by selective use or disuse of organs, organisms acquired or lost certain traits during their lifetime. These traits could then be passed on to their offspring. Over time, this process led to changes in a species.

  15. 15.2 Ideas that Shaped Darwin’s Thinking 1. Tendency toward Perfection Organisms are continually changing and acquiring features that help them live more successfully in their environment.

  16. 15.2 Ideas that Shaped Darwin’s Thinking 2. Use and Disuse Organisms can alter the size and shape of organs by using their bodies in new ways or by not using particular organs. 3. Inheritance of Acquired Traits If an organism alters a body structure, those altered traits can be inherited.

  17. Lamarck’s Theory of Evolution

  18. 15.2 Ideas that Shaped Darwin’s Thinking C. Evaluating Lamark’s hypothesis 1. Lamark did not know how traits were inherited. 2. He did not know an organism’s behavior had no effect on its heritable traits. 3. Lamark was one of the first to develop a hypothesis of evolution and realized organisms adapt to their environments.

  19. 15.2 Ideas that Shaped Darwin’s Thinking II. Population Growth (1798) A. Malthus reasoned that if human population continued to grow unchecked, sooner or later there would be insufficient livingspace and food. B. Forces that work against growth were war, famine, and diseases.

  20. 15.3 Darwin Presents His Case I. Inherited Variation and Artificial Selection A. Inherited Variation 1. Darwin observed variation in species existed in nature and on farms. 2. Some of these variations were heritable, meaning the can be passed from parents to offspring.

  21. 15.3 Darwin Presents His Case 3. Breeders used heritable variation to improve crops and livestock. B. Artificial Selection – selection by humans for breeding of useful traits from natural variation among different organisms.

  22. 15.3 Darwin Presents His Case II. Evolution by Natural Selection A. The Struggle for Existence 1. Darwin was convinced that artificial selection worked in nature.

  23. 15.3 Darwin Presents His Case 2. Struggle for existence – members of each species compete regularly to obtain food, living space, and other necessities of life. 3. The biggest, strongest, faster, better camouflaged, or better protected were able to survive.

  24. 15.3 Darwin Presents His Case B. Survival of the Fittest 1. A key factor in the struggle for existence was how well suited an organism is to its environment. 2. Fitness – the ability of an individual to survive and reproduce in its specific environment.

  25. 15.3 Darwin Presents His Case 3. Adaptation – any inherited characteristic that increases an organism’s chance of survival. 4. Adaptations can be anatomical or structural, physiological processes or functions, and behavior.

  26. 15.3 Darwin Presents His Case 5. Survival of the fittest – Individuals of a species that are better suited to their environment survive and reproduce most successfully. 6. Natural Selection – Darwin referred to survival of the fittest as natural selection. 7. Over time, natural selection results in changes in the inherited characteristics of a population. These changes increase a species’ fitness in its environment.

  27. 15.3 Darwin Presents His Case III. Evidence of Evolution A. Darwin argued that living things have been evolving on Earth for millions of years. Evidence for this process could be found in the fossil record, the geological distribution of living species, homologous structures of living organisms, and similarities in early development, or embryology.

  28. 15.3 Darwin Presents His Case B. Fossil Record 1. Fossils – remains of ancient life. 2. Scientist compare fossils in older rock layers with fossils in younger rock layers and could document how species changed over time.

  29. 15.3 Darwin Presents His Case C. Geographic Distribution of Living Species 1. Darwin observed entirely different species on different continents. 2. Yet, these continents had similar environments and the different species had similar anatomical structures and behaviors.

  30. 15.3 Darwin Presents His Case 3. Because of the similar ecological conditions, these species are exposed to similar pressures of natural selection. Because of these similar pressures, different animals ended up evolving similar features.

  31. Geographic Distribution of Living Species Beaver Beaver Muskrat Beaver andMuskrat Coypu Capybara Coypu andCapybara NORTH AMERICA Muskrat Capybara SOUTH AMERICA Coypu

  32. 15.3 Darwin Presents His Case D. Homologous Body Structures 1. Homologous structures – structures that have different mature forms but develop from the same embryonic structures. Ex. The forelimbs of vertebrates.

  33. 15.3 Darwin Presents His Case 2. Homologous structures provide strong evidence that all four-limbed vertebrates have descended, with modifications, from common ancestors. 3. Similarities and differences help biologists group animals according to how recently they last shared a common ancestor.

  34. Homologous Body Structures Turtle Alligator Bird Mammal Ancient lobe-finned fish

  35. 15.3 Darwin Presents His Case 4. vestigial organs – organs that are reduced in size that they are just vestiges or traces, of homologous organs.

  36. 15.3 Darwin Presents His Case E. Similarities in Embryology 1. Many species look similar during the early stages of development. 2. Some groups of embryonic cells develop in the same order and in similar patterns to produce tissues and organs of all vertebrates. 3. These common cells and tissues produce the homologous structures discussed earlier.

  37. The fossil record Geographic distribution of living species Homologous body structures Similaritiesin early development Physical remains of organisms Common ancestral species Similar genes Similar genes Concept Map Evidence of Evolution includes which is composed of which indicates which implies which implies

  38. 15.3 Darwin Presents His Case IV. Summary of Darwin’s Theory A. Individual organisms differ, and some of this variation is heritable. B. Organisms produce more offspring than can survive, and many that do survive do not reproduce.

  39. 15.3 Darwin Presents His Case C. Because more organisms are produced than can survive, they compete for limited resources. D. Individuals best suited to their environment survive and pass their heritable traits to their offspring. E. The process where diverse species evolved from common ancestors, unites all organisms on Earth into a single tree of life.

  40. 15.3 Darwin Presents His Case V. Strengths and Weaknesses of Evolutionary Theory A. Evolutionary theory offers vital insights to all biological and biomedical sciences, from infectious-disease research to ecology. Evolution is called the “grand unifying theory of the life sciences.” B. Evolution theory is continually changing as new data are gathered and new ways of thinking arise.

  41. CH. 16.3 THE PROCESS OF SPECIATION I. Speciation A. Speciation - the formation of new species. B. Species - is a group of organisms that breed with one another and producefertileoffspring.

  42. CH. 16.3 THE PROCESS OF SPECIATION 1. This means that individuals in the same species share a common gene pool. 2. A genetic change that occurs in one individual can spread through the population. 3. If the genetic change increases fitness, that allele will eventually be found in many individuals of that population.

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