15 Darwin's Theory of Natural Selection 15-1 The Puzzle of Life's Diversity

Transcription

1 15-1 The Puzzle of Life's Diversity Study the photo of leaves... What else do you see? How did the Leaf Mantis come to look like decaying leaves? Define evolution in its simplest meaning? Review the meaning of theory as applied to the theory of evolution? Who was Charles Darwin, generally? Did he discover the theory of evolution? Define natural selection, generally? 1

2 Voyage of the HMS Beagle (1831) Study this map... Identify the significance of the HMS Beagle to our study of evolution, How long was the voyage? What was the primary mission? Why did Darwin go along? What did Darwin do extraordinarily well that was significant? What locations were especially significant? Why? What did Darwin do between stops and how was this significant?... 2

3 Lamarck's Evolution Hypotheses Fig. 1 When did Jean-Baptiste Lamarck live and work in relation to Darwin? What did Lamarck know that was correct? (evolve, descend, adapt) Study the diagrams...what do the arrows represent? Are these 4 different giraffes? What part is missing (Fig. 1)? Explain fully how Lamarck thought species evolved? Define inheritance of acquired characteristics. Why is it also known as use disuse? Was his hypothesis correct? What was he lacking? What did he not know? Has there ever been evidence that, at least in part, supports his hypothesis? Fig. 2 3

4 An Ancient, Changing Earth When did James Hutton work in relation to Darwin? What was Hutton's field of study? What did Hutton observe, theorize and write about? Define gradualism citing one example? How was this important to Darwin's thinking? James Hutton (1795) 4

5 An Ancient, Changing Earth Appalachian Mountains Rocky Mountains When did Charles Lyell work in relation to Darwin? What was Lyell's field of study? Who's work did Lyell's build upon? What did Lyell observe, theorize and write about? Define uniformitarianism citing one example? How was this important to Darwin's thinking? Complete the following: If the Earth has changed over billions of years, then... Charles Lyell (1830) The Grand Canyon 5

6 Population Growth Thomas Malthus (1798) When did Thomas Malthus work in relation to Darwin? What was Malthus's field of study? What did Malthus observe, theorize and write about? Define carrying capacity citing one example? Define limiting factor citing one example? How was this important to Darwin's thinking? If this is true for humans, then... 6

7 Darwin's Observations Grasslands on four different continents What did Darwin observe concerning species living in the same habitat on different continents? Explain why this was unexpected. What did he conclude? What did Darwin observe in fossils? Explain why this was unexpected. What did he conclude? 7

8 Darwin's Observations What did Darwin observe when comparing species on the Galapagos with mainland species? What did he conclude? What did he observe when comparing species on different islands? What did he conclude? What did the combination of observations and acquired knowledge lead him too propose? Give your interpretation of the political cartoon (right). 8

9 Publication of The Origin of Species What did Darwin do on return to England? What did he receive from Alfred Russell Wallace in 1858? Who was Alfred Russell Wallace? What did he discover and where? Give your interpretation of the political cartoon (above, right). What happened next? Why doesn't Wallace get the same recognition? What did Darwin write about?... 9

10 Darwin wrote about Artificial Selection Study the diagram... Explain what it shows in your own words. Define and explain artificial selection. What's with the pigeons? Define domestication and list some domesticated species. Brussels Sprouts Explain how this supports Darwin's natural selection hypothesis. Cauliflower Broccoli Ancestral Species (Brassica oleracea) Kohlrabi Kale 10

11 Darwin wrote about Evolution by Natural Selection List the principles of natural selection that Darwin proposed. Interpret each of these cartoons to identify and explain three misconceptions concerning evolution by natural selection. 11

12 Darwin wrote about Inherited Variation How were differences between individuals of the same species explained before Darwin? How did Darwin view them? Variations in organisms are due to variation in? Identify, list and describe three sources of genetic variation. (mutation (2 types), gene shuffling, horizontal transfer) Did Darwin know this? What did he know? Explain variation as a component of natural selection. 12

13 Darwin wrote about Overproduction Of Offspring Explain overproduction of offspring as a component of natural selection. Review where Darwin got this idea. 13

14 Darwin wrote about The Struggle for Existence Explain how overproduction of offspring can be a problem. What does this lead to or cause? Who might individuals be forced to compete with? (at least 3) 14

15 Darwin wrote about Differential Survival & Reproduction Which individuals survive? Define evolutionary fitness. Study the extreme example above. Define evolutionary adaptation. Identify and explain the adaptations necessary for this moth species to exist in terms of fitness. Explain the cartoon example in terms of fitness. 15

16 Darwin wrote about Descent With Modification Define descent with modification. What is it in contrast to (Lamarck)? Explain the Giraffe example in terms of natural selection and fitness using the terms selected for and selected against. Review what unit changes? What increases in the population? 16

17 Study this phylogenetic tree. Define phylogeny. How much of life is this tree intended to represent? Why are there so many different kinds of life and billions of species? What general trend can be observed from bottom to top? All branches join with other branches and eventually the trunk. What does this represent (at least 3 concepts)? Darwin wrote about Unity and Diversity 17

18 Modern Evidence of Evolution How long has life been evolving? How do we know? List five sources of evidence represented by each of these figures. 18

19 Evidence: The Fossil Record Study this figure representing the fossil record. Define geologic strata. Describe the relationship between strata and time. Does the same always hold true for depth and time? Explain! Generally, what can be inferred about life on Earth from the fossil record? Specifically, observe the fossils in this figure to construct a phylogenetic tree that shows the evolution of the six major animal groups (invertebrates + 5 vertebrates). 19

20 Evidence: Geographic Distribution (AKA Biogeography) Study these figures showing Galapagos finch species? What did Darwin conclude to explain their similarities? What did Darwin conclude to explain their differences? What two inferences can be made concerning species on the same island? Explain how this idea applies to global biogeography (Darwin's realization). 20

21 Evidence: Biogeography Study the figure comparing marsupial and placental mammals? What is it designed to show? (AKA parallel evolution) Study the figure comparing North and South American placental species? What is it designed to show? Define convergent evolution. Define analogous structure. 21

22 Turtle Alligator Bird Mammal Evidence: Homologous Structures Vestigial What's missing? Ancient, lobe-finned fish Which vertebrate group is missing from the phylogenetic tree? What does the color coding suggest about the bone structure of these groups? Define homologous structure. Why is the bone structure not identical? Define divergent evolution. Why does a whale have pelvic bones, snakes have hind claws and humans have an appendix? Define vestigial structure. Contrast with analogous structure. 22

23 Evidence: Similarities in Embryology Study these figures and read the captions. What does this comparisons of embryos appear to show? Ontogeny Recapitulates Phylogeny Translate and contemplate this phrase. Is it true? 23

24 Summary of Darwin's Theory List and explain the four components of natural selection. 1) Variation: Individual organisms differ, and some of this difference is heritable. 2) Overproduction of offspring: Organisms produce more offspring than can survive and reproduce. 3) Struggle for existence: Because more organisms are produced than can survive and reproduce, they compete for limited resources. 4) Differential survival and reproduction: Individuals best suited to their environment (more fit) survive and/or produce more offspring. These organisms pass their adaptive traits to their offspring. Other individuals (less fit) die and/or leave fewer offspring. This process of natural selection causes species to change over time (evolve). It is the primary MECHANISM OF EVOLUTION! 24

25 Summary of Darwin's Theory What does this suggest about all species alive today? 1) They descended with modification from ancestral species. 2) They are united into one tree of life! Is biology the only field of study that supports Darwin's hypotheses? Is evolutionary theory subject to change? Explain! 25