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Continuity Through Evolution

Continuity Through Evolution. Chapter 16 . LEARNING OBJECTIVE 1. Discuss the historical development of the theory of evolution. Jean Baptiste de Lamarck. First scientist to propose that organisms undergo change over time as a result of some natural phenomenon rather than divine intervention

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Continuity Through Evolution

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  1. Continuity Through Evolution Chapter 16

  2. LEARNING OBJECTIVE 1 • Discuss the historical development of the theory of evolution

  3. Jean Baptiste de Lamarck • First scientist to propose that organisms undergo change over time as a result of some natural phenomenon rather than divine intervention • Thought organisms could pass traits acquired during their lifetimes to their offspring

  4. Charles Darwin • Theory of evolution based on his observations while voyaging on HMS Beagle • Tried to explain similarities between animals and plants of arid Galápagos Islands and humid South American mainland

  5. Voyage of HMS Beagle

  6. Plants and Animals of Galápagos Islands

  7. Fig. 16-2a, p. 314

  8. Fig. 16-2b, p. 314

  9. Fig. 16-2c, p. 314

  10. Fig. 16-2d, p. 314

  11. LEARNING OBJECTIVE 2 • Define evolution • Explain the four premises of evolution by natural selection as proposed by Darwin

  12. KEY TERMS • EVOLUTION • Accumulation of inherited changes within populations over time • ADAPTATION • An evolutionary modification that improves an organism’s chances of survival and reproductive success

  13. KEY TERMS • NATURAL SELECTION • Mechanism of evolution in which individuals with inherited characteristics well suited to the environment leave more offspring than do individuals that are less suited to the environment

  14. Darwin’s Premises of Evolution by Natural Selection (1) Overproduction: • Each species produces more offspring than will survive to maturity (2) Inherited variation: • Individuals in a population exhibit inheritable variation in their traits

  15. Darwin’s Premises of Evolution by Natural Selection (3) Limits on population growth: • Organisms compete with one another for food, space, water, light, other resources needed for life

  16. Darwin’s Premises of Evolution by Natural Selection (4) Differential reproductive success: • Offspring with the most favorable combination of characteristics are most likely to survive and reproduce, passing those genetic characteristics to the next generation

  17. LEARNING OBJECTIVE 3 • Compare the modern synthesis with Darwin’s original theory of evolution

  18. Darwin’s Theory of Evolution • Darwin could not explain how traits were passed from one generation to another or why individuals vary within a population

  19. KEY TERMS • MODERN SYNTHESIS • A comprehensive, unified explanation of evolution based on combining previous theories, especially of Mendelian genetics, with Darwin’s theory of evolution by natural selection

  20. LEARNING OBJECTIVE 4 • Briefly discuss the evidence for evolution obtained from the fossil record

  21. KEY TERMS • FOSSIL • A part or trace of an ancient organism, usually preserved in sedimentary rock

  22. Fossils • Provide • a record of earlier plants and animals • understanding of where and when they lived • an idea of their lifestyles • Fossils of organisms of different geologic ages trace lines of evolution that gave rise to those organisms

  23. Plant Fossils

  24. LEARNING OBJECTIVE 5 • Summarize the evidence for evolution derived from comparative anatomy

  25. KEY TERMS • HOMOLOGOUS FEATURES • Dissimilar structures with an underlying similarity of form and development that occur in different species with a common ancestry • Indicate evolutionary ties between the organisms possessing them

  26. Homologous Features

  27. Tendril Spine Leaflet Leaf petiole Stipule Stem (b) The tendrils of the garden pea (Pisum sativum) are also modified leaves. Leaves of the garden pea are compound, and the terminal leaflets are modified into tendrils that are frequently branched. Note the leafy stipules at the base of the leaf; the stipules in the garden pea are often larger than the leaflets. (a) The spines of the fishhook cactus (Ferocactus wislizenii) are modified leaves. Fig. 16-4, p. 319

  28. KEY TERMS • HOMOPLASTIC FEATURES • Structures in unrelated species that are similar in function and appearance but not in evolutionary origin • Are the result of convergent evolution

  29. KEY TERMS • CONVERGENT EVOLUTION • Independent evolution of similar adaptations in unrelated speciesliving in similar environments

  30. Homoplastic Features

  31. Shoot (develops from axillary bud) Thorn (develops from axillary bud) Spine (midrib of leaf) Leaf scar (a) A spine of Japanese barberry (Berberis thunbergii) is a modified leaf. (In this example, the spine is actually the midrib of the original leaf, which has been shed.) (b) Thorns of downy hawthorn (Crataegus mollis) are modified stems that develop from axillary buds formed during the previous year's growth. Fig. 16-5, p. 320

  32. Convergent Evolution

  33. KEY TERMS • VESTIGIAL STRUCTURE • An evolutionary remnant of a formerly functional structure • Occasionally present as an ancestral species adapts to a different mode of life

  34. Vestigial Structure

  35. Stamens Sepal Reduced petal Fig. 16-7, p. 321

  36. Mimicry

  37. LEARNING OBJECTIVE 6 • Define biogeography

  38. KEY TERMS • BIOGEOGRAPHY • Study of the geographic distribution of living organisms and fossils • Geographic distribution affects organism’s evolution • Areas isolated for a long time have plants and animals unique to those areas

  39. LEARNING OBJECTIVE 7 • Describe how scientists make inferences about evolutionary relationships among organisms from the sequence of amino acids in specific proteins or the sequence of nucleotides in particular genes

  40. Biochemistry and Molecular Biology • Amino acids in common proteins • Such as cytochrome c • Sequence is more similar in closely related species than in remotely related species • Sequence of nucleotides in DNA • Greater proportion identical in closely related organisms than in remotely related organisms

  41. Experiment: Pollinator Preferences

  42. Wild-type M. lewisii Fig. 16-9a, p. 324

  43. Animation: The Galapagos Island CLICKTO PLAY

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