Evolution

1. Evolution Chapters 16,17, 26

2. 16.1 Darwin’s Voyage of Discovery • Big Idea: Darwin developed a scientific theory of biological evolution that explains how modern organisms evolved over long periods of time through descent from common ancestors.

3. What is evolution? • An orderly succession of changes. • Process of change over time.

4. Charles Darwin (a.k.a. Chucky-D) • 1809-1882 • Proposed that species were modified by natural selection.

5. Describe Darwin’s background before his voyage on the beagle. • He first attended medical school and was grossed out by the sight of blood • Then he enrolled in school to be a clergy man, but was unable to council people. • After failing at both he did not know what he wanted to do . • Then he was offered the voyage of a lifetime……

6. H.M.S. Beagle • He was a naturalist for the expedition • It was a 5 year mapping and collecting expedition. • Toured South America and South Pacific.

7. What three patterns of biodiversity did Darwin note? • Species Vary Globally: Darwin noticed that different, yet ecologically similar, animal species inhabited separated, but ecologically similar, habitats around the globe. • Example. Grasslands produce varied species around the globe. • Australia: kangaroos • Europe: rabbits • Africa: gazelle • Why are there no kangaroos in Europe?

8. What three patterns of biodiversity did Darwin note? Cont. • Species Vary Locally: Darwin noticed tat different, yet related, animal species often occupied different habitats within a local area. • There were different Giant Land Tortoises on each of the Galapagos Islands.

9. What three patterns of biodiversity did Darwin note? Cont • Species Vary Over Time: Darwin noticed that some fossils of extinct animals were similar to living species. • He collected fossils of extinct organisms. • Why are these animals extinct? • Noticed that some are versions of current organisms. • EX: Glyptodant vs. armadillo

10. Jean Baptiste Lemark(1744-1829) • A encyclopedia author. • Developed the word invertebrate. • Was the first to propose a unifying hypothesis of species modification

11. What was Lamarck’s theory? • Similar species descended from a common ancestor- thus, living species were descended from similar extinct species evident in the fossil record.

12. Explain an acquired trait. • Is a trait that is not determined by genes. • It arises during an organism’s lifetime as a result of the experiences or behaviors. • Ex. He believed that the webbed feet of shore birds resulted from the repeated stretching of the feet, not from an inherited gene.

13. What part of Lamarck’s theory is useful today? • He was the first to state that organisms change over time and that new types of organisms are modified descendants of older organisms.

14. What is Artificial Selection? In artificial selection, nature provides the variations, and humans select those they fine useful. Example Mustard Family

15. What are the three major parts of the Evolution by natural selection theory? • The Struggle for Existence. • Variation and Adaptation • Survival of the Fittest

16. What is “the struggle for survival”? • More individuals are produced than can survive. • Members of a population must compete to obtain food, living space, and other limited necessities of life.

17. What is variation and adaptation? • Populations contain individuals with natural variations among their inheritable traits. • Some of the variations are better suited to life in a particular environment than others. • Example: Members of a predatory species are faster or have longer claws are able to catch more prey.

18. What is an adaptation? • Any heritable characteristic that increases an organism’s ability to survive and reproduce in its environment. • Examples: body structures, biological functions and behaviors • Camouflage • Mimicry • Photosynthesis • Avoidance strategies

19. What is fitness? • An individual with high fitness is well adapted to its environment and reproduces more successfully than an individual with low fitness.

20. What is “Survival of the Fittest”? • Individuals that have trait (adaptations) that are well suited for the environment can survive and reproduce in its environment. • These organisms are said to have high fitness. • Individuals with traits that are not well suited to the environment either die without reproducing or produce little offspring. • The difference in the rates of survival is “survival of the fittest”.

21. What is Natural Selection? • Mechanism for evolution • The process by which organisms with variations most suited to their local environment survive and leave more offspring.

23. When does natural selection occur? • Natural Selection occurs in any situation in which more individuals are born than can survive (struggle for existence ); there is natural heritable variation (variation and adaptation); and there is variable fitness among individuals (survival of the fittest.)

24. Give two reasons why the following statement is false.“ The goal of natural selection is to produce perfect organisms.” • Because natural selection is a natural process; it cannot have goals. • Natural selection could never produce perfect organisms because environments change and no organism is “better” or more perfect than any other at adjusting to future changes.

25. What does Darwin’s mechanism for evolution suggest about living and extinct species? • All species- living and extinct- are descended from ancient common ancestors. • Natural selection depends on the ability of organisms to reproduce and leave descendants. • Therefore, every organism alive today is descended from parents who survived and reproduced and so forth back in time.

26. How does the distribution of species support evolution? • Patterns in the distribution of living fossil species tell us how modern organisms evolved from their ancestors. • Closely Related but Different: biogeography of Galapagos species suggested that population on the island had evolved from mainland species. Over time, natural selection on the islands produced variations that resulted in different, but closely related island species. • Distantly Related but Similar: Similar habitats produce organisms that are similar and distantly related. Example: the ground-dwelling birds of grasslands.

27. What is biogeography? • The study of where organisms live now and where they and their ancestors lived in the past.

28. How do fossils support evolution? • Many recently discovered fossils form series that trace the evolution of modern species from extinct species. • Evolution takes a long time, and life on earth must be old. (4.6 Million)

29. Example: Whales

30. Define homologous. • Similar features that originated in a shared ancestor • Example: beaks of birds; forelimbs of animals.

31. What are homologous structures? • Structures that are shared by related species and that have been inherited from a common ancestor.

32. How do homologous structures support evolution? • Organisms that share homologous structures have descended with modification from a common ancestor. • Similarities and differences among features of organisms can support.

34. Define analogous (features). • Serve the same function and look some what alike. They derive from differ in development.

35. The wings of humming birds and humming bird moths. Give one example.

36. Define vestigial feature. • Apparently useless features, that no longer serve a function

37. Whale of a tale • Whales have pelvic bones

38. Give two examples. • Human tail bone, and appendix • Snakes have limb bones

39. What clues do vestigial structures provide? • Whales probably descend from a land animal that had legs. • These structures show body parts which function is no longer necessary for reproductive success (survival).

40. What is the significance of embryological studies in evolution? • Ontogeny recapitulates phylogeny • Embryological development repeats a evolutionary history. • In the EARLY stages all vertebrate embryos look alike.

41. How does embryology support evolution? • Similar patterns of embryological development provide further evidence that organisms have descended from a common ancestors.

46. What evidence of evolution comes from molecular biology? • At the molecular level, the universal genetic code and homologous molecules provide evidence of common descent.

47. Explain one similarity in macromolecules. • Closely related organisms have similar macromolecules like DNA, RNA and the protein hemoglobin

48. What about the genetic code supports evolution? • The genetic code is the same for all life forms. The genetic code performs in the same way. • DNA – RNA – Proteins

49. How fast does evolution take place? • Evidence shows that evolution has often proceeded at different rates for different organisms at different times over the long history of life of Earth.

50. What is gradualism? • A slow and steady change. • The idea that organisms have changed gradually over time.