Chapter 16 Darwin s Theory Of Evolution
16-1 I. Evolution A. process by which modern organisms have descended from ancient organisms (change over time) II. Charles Darwin A. Sailed around the world on HMS Beagle in 1831
B. Made observations 1. Patterns of diversity: plant/animal well suited to environment 2. Living Organisms and fossils how related 3. Galapagos Islands a. 1,000 Km W of South America b. Close together but very different climates c. Characteristics of animals/plants varied noticeably 4. Hypothesis life changes over time Now a Theory
III. Changing Earth 16-2 A. Hutton and Lyell 1. Earth is many millions of years old 2. The processes that changed Earth in the past are the same processes that operate in the present B. Influence on Darwin 1. If the Earth could change over time, life might change as well
IV. Species Evolve A. Lamarck 1. Proposed a. selective use or disuse of organs, organisms acquired or lost certain traits during their lifetime (acquired characteristics could be inherited) b. These traits could then be passed on to their offspring 2. Hypothesis = WRONG!!!! a. organism s behavior has no effect on its inheritable characteristics
A male fiddler crab uses its front claw to ward off predators and to attract mates. Page 376
Because the front claw is used repeatedly, it becomes larger. This characteristic (large claw) is passed onto its offspring.
V. Population Growth A. 1798, Thomas Malthus noted that babies were being born faster than people were dying 1. reasoned that if the human population continued to grow = insufficient living space and food B. Darwin realized this pertains to plants and animals 1. If all offspring survived for several generations = overrun the world 2. Key to Darwin s explanation of evolution Survival of the Fittest
16-3 VI. Darwin, 1859, published On the Origin of Species A. proposed a mechanism called natural selection B. evolution has been taking place for millions of years and continues in all living things
VII. Artificial Selection (selective breeding) A. Humans select the useful characteristics provided by nature to provide the next generation Ex. Largest hogs and fastest horses VIII. Natural Selection A. The Struggle for Existence 1. organisms compete for resources (water, food, space, mate)
B. Survival of the Fittest 1. Better suited to the environment = fitness (so the organism can survive and reproduce) 2. Adaptations = inherited characteristic that increases an organism's chance to survive a. Mimicry = Enables one species to resemble another species Milk snake Leaf Frog b. Camouflage = Blend into environment Coral snake
C. The traits being selected contribute to an organism's fitness in its environment
D. Descent With Modification 1. Species have descended, with changes, from other species over time 2. Common Descent All living organisms are related to one another
IX. Evidence of Evolution A. Fossil Record 1. compared fossils - determine that life on Earth has changed over time
B. Geographic Distribution of Living Species 1. Existence of similar but unrelated species due to natural selection in similar environments
Similar, but Unrelated Species Page 383
C. Body Structures 1. Homologous Body Structures a. Similar in arrangement and/or function Page 384
2. Analogous Structures a. NOT similar in structure but similar in function b. Two unrelated species solving the same problem example: wings on birds and butterflies
3. Vestigial Structure a. Reduced structure having no known modern day purpose b. Vestige = remnant of the past example: eyes on mole rats and cavefish, appendix in humans, wings on flightless birds
D. Embryology 1. Embryos of vertebrates have cells that develop in the same order and in similar patterns to produce the tissues/organs 2. Tails and gill slits of all developing species
15-1 Darwin's observations in the Galápagos Islands included all of the following EXCEPT A. characteristics of many living organisms did not vary among the different Galápagos Islands. B. many plants and animals were well suited to their environments. C. very different animals inhabited many similar ecosystems. D. though close together, the islands had very different climates.
15-1 What did Darwin learn about the tortoises of the Galápagos Islands? A. Tortoises with dome-shaped shells were found on all of the islands. B. The tortoises resembled fossil remains that were found on the islands. C. The shape of the Galápagos tortoise shells varied with their different habitats. D. Different shaped tortoise shells occupied the same habitats.
15-1 According to Darwin's proposed theory of evolution, species of organisms A. change over time. B. are not related to fossil remains. C. do not vary from one location to another. D. remain unchanged when the environment changes.
15-1 Darwin hypothesized that different-looking mockingbirds from different islands might be descendants of birds that A. belonged to a single species that had originated on the islands B. belonged to a single species from the South American mainland. C. belonged to a different species from similar habitats in South America. D. had been brought to the islands by earlier visitors.
15-1 What role did the evidence gathered by Darwin play in developing his ideas? A. It immediately gave him the idea that organisms evolved. B. It confirmed evolution an idea he had before he left England. C. It confirmed evolution, which he proved on his arrival in the Galápagos. D. It led to considering the possibility of evolution only after he was heading home.
15 2 Hutton and Lyell recognized that geological processes A. of the past differ from those of the present. B. indicate that Earth is many millions of years old. C. operate quickly, often over thousands of years. D. always involve violent events like volcanoes, earthquakes, and floods.
15 2 The discovery of many fossils challenged the idea that A. acquired traits could be inherited. B. Earth is many millions of years old. C. species had never changed over time. D. geological changes are slow.
15 2 Which of the following scientists proposed the hypothesis of selective use and disuse? A. Charles Darwin B. Jean-Baptiste Lamarck C. Thomas Malthus D. Charles Lyell
15 2 The scientist that proposed that Earth is shaped by geological forces that took place over long periods of time is: A. Malthus B. Hutton C. Darwin D. Lamarck
15 2 Darwin s reading of Thomas Malthus made him realize that A. because of overpopulation, human beings cannot avoid extinction. B. all living things must evolve. C. living things produce more offspring than can possibly survive. D. the basic ideas of Lamarck were wrong.
15-3 The scientist who motivated Darwin to publish On the Origin of Species was A. Alfred Russel Wallace. B. Charles Lyell. C. Jean-Baptiste Lamarck. D. Thomas Malthus.
15-3 Differences among individuals of a single species are referred to as A. artificial selection. B. genetic variation. C. survival of the fittest. D. environmental adaptation.
15-3 Changes that increase a species' fitness in its environment over time are due to A. the principle of common descent. B. the geographic distribution of that species C. natural selection. D. habitat selection.
15-3 An inherited characteristic that increases an organism's chance of survival is called a(an) A. homologous structure. B. vestigial organ. C. adaptation. D. analogous structure.
15-3 Evidence used by Darwin to support the idea of evolution included all the following EXCEPT A. fossils that demonstrate change over time. B. the genetic mechanism by which useful traits are inherited. C. the geographic distribution of living things D. the presence of many homologous structures in plants and animals.