Chapter 15 Theory of Evolution

Transcription

1 Chapter 15 Theory of Evolution

2 1. What is Evolution? All the changes that have formed life on earth from its earliest beginnings to the diversity that characterizes it today. A heritable (genetic) change in the characteristics within a population from one generation to the next.

3 Microevolution vs. Macroevolution Microevolution: changes within a subspecies or gene pool of a species. Small scale changes; studies changes in populations over a few generations. These changes may be due to several processes: mutation, natural selection, artificial selection, gene flow, and genetic drift.

4 Microevolution vs. Macroevolution Macroevolution: Large-scale changes over geological era/time. a scale of analysis of evolution in separated gene pools. Studies evolution ranging from thousands to millions of years ago.

5 2. How is theory defined in science? A well-supported explanation for some aspect of the natural world that incorporates many observations, inferences, and tested hypothesis

6 Scientific Law Generalization Empirical statement of something which always appears to be true Scientific Theory Explanation Attempt to explain what has been observed, natural phenomenon Example: the law of gravity tells us the size of the force, but doesn t explain why gravity exists or why it is as strong as it is In every case, male birds are either similar or more colorful than their female counterparts Example: theory of evolution can explain the fossil record and genetic code of all plants, animals, and other forms of life There is a strong connection between nutrition and a variety of cancers

7 3. What were some ideas about Geology in the 1800 s George Cuvier ( ) French Anatomist Catastrophismsudden geologic catastrophes caused the extinction of large groups of animal at certain points in the past.

8 3. What were some ideas about Geology in the 1800 s Charles Lyell ( ) English Geologist Uniformitarianism Geologic processes have changed the shape of the earth s surface in the past and continue to work in the same ways today

9 4. Who was Jean Lamarck? French Scientist ( ) First to propose that similar species descended from a common ancestor

10 4. Who was Jean Lamarck? To explain how species changed he hypothesized that traits acquired during an organisms lifetime as a result of experience or behavior could be passed onto their offspring

11 4. Who was Jean Lamarck? His hypothesis was fiercely attacked and easily disproved But, he was the first to clearly state that types of organisms changed over time and that similar types of organisms are modified descendents of older types.

12 5. Who was Charles Darwin? An English Naturalist ( ) He proposed the hypothesis that species were modified by natural selection

13 Charles Darwin From he was a naturalist on board the H.M.S. Beagle for a 5 year mapping and collecting expedition to South America and the South Pacific. While on board the ship he collected 100 s of specimens and fossils and kept careful records of his observations.

14 When he returned he analyzed his data over a period of 20 years and finally published his work on evolution by natural selection. He wrote a famous book which was published in 1859 called On the Origin of Species

15 6. What were Darwin s two Theories? 1. Descent with Modification every species must have descended by reproduction from existing species and that species must be able to change over time (Describes the process of evolution)

16 Darwin s Theories 2. Theory of Natural Selection - Describes the mechanism or how evolution occurs. - It has five important parts:

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18 Natural Selection c) struggle to survive individuals must compete with each other; some variations improve and others reduce an individual s ability to survive and reproduce.

19 Natural Selection d) Organisms best suited for their environment survive e) Organisms that survive pass their traits on to their offspring

20 6. What are Darwin s two Theories? **The resulting change in the genetic makeup of a population is Evolution. **In an evolving population, a single organism s genetic contribution to the next generation is termed Fitness. A fit individual is one that has offspring that also live long enough to reproduce.

21 Who was Charles Darwin? Charles Darwin was

22 Why was Charles Darwin revolutionary? Charles Darwin was considered revolutionary because

23 What was Charles Darwin s contribution? The contribution that Charles Darwin made was

24 Who is more likely to survive? A B

25 7. How are traits chosen to be favorable? The environment selects the traits that will increase a population. The kinds of traits that are favorable depend on the demands of the environment. A favorable trait is known as an adaptation as it gives an organism an adaptive advantage. Write this in the margin Adaptation: A favorable trait that helps an organism survive.

26 7. How are traits chosen to be favorable? Adaptation is an inherited trait (genetic) that increases an organism s chance of survival. Adaptations can be anatomical, physiological, or behavioral (instinctual) and will happen over many successive generations An acclimation is a short term learned response to an environmental change.

27 Adaptation or Acclimation? Dolphins learn to perform tricks to entertain humans.

28 Adaptation or Acclimation? Leopard sharks have a huge amount of body fat so that they an withstand the cold ocean water.

29 Adaptation or Acclimation? Chameleons change their skin color to hide in their surroundings

30 Adaptation or Acclimation? A lizard s legs grew longer after they were broken from falling off a tall rock

31 Adaptation or Acclimation? Volcan Darwin tortoises of the Galapagos Islands have domed shells

32 Adaptation or Acclimation? A dog ignores a bee hive because it learned it will get stung

33 Adaptation or Acclimation? Redwood trees have a chemical called tannin that helps keep bugs and fungus away.

34 Adaptation or Acclimation? A stronger baby finch takes food from a smaller sibling

35 Adaptation or Acclimation? A raccoon lost its hair in a fire and now is camouflaged.

36 Adaptation or Acclimation? You put on a rain coat because you notice rain clouds overhead

37 8. Who was Steven Jay Gould American Paleontologist ( ) He developed the theory called Punctuated Equilibrium which describes a pattern of species formation where evolutionary change occurs relatively rapidly followed by comparatively longer periods of evolutionary stability (lack of change).

38 9. What is a fossil? Any evidence of change from the past The remains or traces of long-dead organisms (most are hard parts, such as bones, teeth, shells, and woody stems)

39 10. Where are fossils found? 1. Sedimentary rock layers called strata

40 10. Where are fossils found? 2. Frozen in ice (wooly mammoth)

41 10. Where are fossils found? 3. Stuck in tree sap or amber (insects)

42 10. Where are fossils found? 4. Stuck in tar (saber tooth tigers)

43 11. Fossils are not always body parts, but can be Imprint a film of carbon remains after an organism decays Mold an imprint or impression in a rock of the shape or track of an organism

44 11. Fossils are not always body parts, but can be Cast when sediments or hard minerals fill in a cavity left by a fossil mold; internal mold

45 11. Fossils are not always body parts, but can be Replacement when sediments or hard minerals replace the whole organism (example: petrified wood)

46 12. What do we call Scientists Who Study Fossils

47 13. How do scientists know how old fossils are? Relative Age the fossil s age compared or related to another fossil. Absolute Age can be estimated from surrounding igneous or metamorphic rock that has been directly dated. (numerical age)

48 14. What is Radiometric Dating? Technique used to establish absolute age. The age of certain types of fossils can be determined by measuring the amount of a particular isotope it contains.

49 14. What is Radiometric Dating? This quantity is then compared with the amount of some other substance in the fossil that remains constant over time.

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51 15. What is the Geologic Time Scale? A timeline for the order in which different groups of rocks and fossils were formed; a time scale for the history of the earth

52 Major Geologic Eras Precambrian 4.5 bya-600 mya Paleozoic 600 mya- 225 mya Mesozoic 225 mya-2.5 mya Cenozoic 2.5mya present

53 16. What has the fossil record shown scientists? Fossil-bearing strata show that species of organisms appear, existed for awhile, and then disappear or became extinct

54 16. What has the fossil record shown scientists? The fossil record indicates that there were several mass extinctions, which are brief periods during which large numbers of species disappeared e.g. trilobites disappeared during the Permian extinction 245 million years ago.

55 17. What are some evidences from living organisms to support evolution by natural selection? 1. Common Ancestry Some species have evolved from one common ancestor Ex. finches and tortoises Eastern long neck turtle and desert turtle

56 2. Homologous Structuresanatomical structures that occur in different species that are embryologically and structurally similar, but have different functions ( SAME STRUCTURE, DIFFERENT FUNCTION) ex. Forelimbs of humans, cats, whales, and bats

57 3. Analogous Structures anatomical structures that occur in different species that have similar, but do not come from the same ancestral structure. (DIFFERENT STRUCTURE, SAME FUNCTION) ex. Wings

58 4. Vestigial Structures organs or structures that seem to serve no function but that resemble structures with functional roles in related organisms ex. human tailbone, whale pelvis

59 5. Embryological Similarities some stages of vertebrate embryo development are very alike which may be evidence that they share a common ancestor and have inherited similar stages of development

60 6. Similarities in Macromolecules the greater the similarities in DNA, RNA, and proteins (amino acid sequence) in different species, the more closely related they are assumed to be through a common ancestor.

61 18. What are the different patterns of evolution? 1. Coevolution- the changes of two or more species in close association with each other ex. Predators and their prey Parasites and their host Herbivores and plants Plants and animals that Pollinate (flower and bee)

62 Coevolution Two or more species evolve together

63 18. What are the different patterns of evolution? 2. Convergent Evolution - unrelated species become more and more similar as they adapt to the same kind of envirnoment. ex. sharks and dolphins

64 Patterns of Evolution 3. Divergent Evolution -

65 Patterns of Evolution 3. Divergent Evolution - two or more related populations or species become more and more dissimilar; usually occurs as a response to differing habitats.

66 Divergent Two or more species become more dissimilar

67 Divergent Evolution a. Adaptive Radiation- many related species evolve from a single ancestral species. (finches common ancestory) b. Artificial Selectionhumans choose which organisms to breed based on those that have desired traits. (dogs)

68 19. What is industrial melanism? A preference for the darkness of the skin, feathers, or fur in a population of organisms living in an industrial region where the environment is soot-darkened E.g. moths in England