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1 Evolution Diversity of Life copyright cmassengale.

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1 1 Evolution Diversity of Life copyright cmassengale

2 Why did you pick the candy you did? Why did you pick the candy you did? What are some reasons you didn’t pick certain candy? What are some reasons you didn’t pick certain candy? What candy “survived” What candy “survived” copyright cmassengale2

3 Natural Selection Process by which populations change in response to their environment as individuals better adapted to the environment leave more offspring than those individuals not suited to the environment Process by which populations change in response to their environment as individuals better adapted to the environment leave more offspring than those individuals not suited to the environment Adaptations are the changes that occur in a species that results in organisms being better suited to its environment Adaptations are the changes that occur in a species that results in organisms being better suited to its environment copyright cmassengale3

4 Natural Selection All species have genetic variation. All species have genetic variation. The environment presents many different challenges to an individuals ability to reproduce. The environment presents many different challenges to an individuals ability to reproduce. Organisms tend to produce more offspring than their enviornment can support Organisms tend to produce more offspring than their enviornment can support copyright cmassengale4

5 Natural Selection Individuals within a population that are better able to cope with the challenges of their environment tend to leave more offspring than those less suited to the environment. Individuals within a population that are better able to cope with the challenges of their environment tend to leave more offspring than those less suited to the environment. The traits of individuals best suited to a particular environment tend to increase in a population over time. The traits of individuals best suited to a particular environment tend to increase in a population over time. copyright cmassengale5

6 Evolution Change in the genetic makeup of a population or species over time Change in the genetic makeup of a population or species over time Four major points that support the theory of Evolution Four major points that support the theory of Evolution copyright cmassengale6

7 Theory of Evolution Variation exists within the genes of every population or species (result of random mutation) Variation exists within the genes of every population or species (result of random mutation) In particular environment, some individuals of a population or species are better suited to survive (as a result of variation) and have more offspring In particular environment, some individuals of a population or species are better suited to survive (as a result of variation) and have more offspring copyright cmassengale7

8 Evolution Over time, the traits that make certain individuals of a population able to survive and reproduce tend to spread in the population. Over time, the traits that make certain individuals of a population able to survive and reproduce tend to spread in the population. There is clear proof from fossils and many other sources that living species evolved from organisms that are extinct. There is clear proof from fossils and many other sources that living species evolved from organisms that are extinct. copyright cmassengale8

9 9 “Nothing in biology makes sense EXCEPT in the light of evolution.” Theodosius Dobzhansky Evolution Charles Darwin in later years copyright cmassengale

10 10 History of Evolutionary Thought copyright cmassengale

11 11 Charles Darwin the Naturalist copyright cmassengale

12 12 Voyage of the Beagle Charles Darwin Born Feb. 12, 1809 Born Feb. 12, 1809 Joined Crew of HMS Beagle, 1831 Joined Crew of HMS Beagle, 1831 Naturalist Naturalist 5 Year Voyage around world 5 Year Voyage around world copyright cmassengale

13 13 HMS Beagle’s Voyage copyright cmassengale

14 14 Evidence for Evolution – The Fossil Record copyright cmassengale

15 15 The Galapagos Islands Finches on the islands resembled a mainland finch from South American Finches on the islands resembled a mainland finch from South American More types of finches appeared on the islands where the available food was different (seeds, nuts, berries, insects…) More types of finches appeared on the islands where the available food was different (seeds, nuts, berries, insects…) Finches had different types of beaks adapted to their type of food gathering Finches had different types of beaks adapted to their type of food gathering copyright cmassengale

16 16copyright cmassengale

17 17 Lamarck’s Theory of Evolution Jean-Baptiste Lamarck, 1809 Jean-Baptiste Lamarck, 1809 One Of First Scientists To Understand That Change Occurs Over Time One Of First Scientists To Understand That Change Occurs Over Time Stated that Changes Are Adaptations To Environment acquired in an organism’s lifetime Stated that Changes Are Adaptations To Environment acquired in an organism’s lifetime Said acquired changes were passed to offspring Said acquired changes were passed to offspring copyright cmassengale

18 18 Lamarck’s Theory of Evolution Idea called Law of Use and Disuse Idea called Law of Use and Disuse If a body part were used, it got stronger If a body part were used, it got stronger If body part NOT used, it deteriorated If body part NOT used, it deteriorated copyright cmassengale

19 19copyright cmassengale

20 20 Lamarck’s Theory of Evolution Inheritance Of Acquired Traits Inheritance Of Acquired Traits –Traits Acquired During Ones Lifetime Would Be Passed To Offspring Clipped ears of dogs could be passed to offspring! copyright cmassengale

21 21 Darwin’s Conclusion Production of more individuals than can be supported by the environment leads to a struggle for existence among individuals Only a fraction of offspring survive each generation Survival of the Fittest copyright cmassengale

22 22 The Struggle for Existence Malthus’ Influence and Key Associations- Darwin’s key association was that individuals that have physical or behavioral traits that better suit their environment are more likely to survive and reproduce than those that do not have such traits. Darwin’s key association was that individuals that have physical or behavioral traits that better suit their environment are more likely to survive and reproduce than those that do not have such traits. copyright cmassengale

23 23 Darwin’s Conclusion Individuals who inherit characteristics most fit for their environment are likely to leave more offspring than less fit individuals Called Natural Selection copyright cmassengale

24 24 Publication of “On The Origin of Species” He Refused To Publish Until He Received An Essay From Alfred Wallace He Refused To Publish Until He Received An Essay From Alfred Wallace –Fellow Naturalist –Independently Developed The Same Theory –After 25 Years, Someone Else Had Come To The Same Conclusions From Their Observations Of Nature copyright cmassengale

25 25 Survival of the Fittest Key Concept Over Time, Natural Selection Results In Changes In The Inherited Characteristics Of A Population. These Changes Increase A Species Fitness In Its Environment copyright cmassengale

26 26 Natural Selection Cannot Be Seen Directly Cannot Be Seen Directly It Can Only Be Observed As Changes In A Population Over Many Successive Generations It Can Only Be Observed As Changes In A Population Over Many Successive Generations –Radiation –Fossil Record copyright cmassengale

27 27. Major Problem in Darwin’s Theory No mechanism to explain natural selection How could favorable variations be transmitted to later generations? With the rediscovery of Mendel’s work in the first half of the 20th century, the missing link in evolutionary theory was found copyright cmassengale

28 28 Opposition to Evolution The upheaval surrounding evolution began with Darwin’s publication of On the Origin of Species By Means of Natural Selection The debate continues nearly 150 years later copyright cmassengale

29 Isolation Process by which two populations of the same species cannot breed with one another. Process by which two populations of the same species cannot breed with one another. Geographically species populations become separated, and change independently over time. Geographically species populations become separated, and change independently over time. At some point they are so different they can no longer breed and are two distinct species. At some point they are so different they can no longer breed and are two distinct species. copyright cmassengale29

30 30 Theory of Evolution Today Supporting Evidence copyright cmassengale

31 31 Evidence of Evolution Key Concept Darwin Argued That Living Things Have Been Evolving On Earth For Millions of Years. Evidence For This Process Could Be Found In: –The Fossil Record –Homologous Structures of Living Organisms –Protein and DNA similarities –Similarities In Early Development copyright cmassengale

32 32 Fossil Record Provide the most direct evidence that evolution has taken place Provide the most direct evidence that evolution has taken place Fossils In Different Layers of Rock (sedimentary Rock Strata) Showed Evidence Of Gradual Change Over Time Fossils In Different Layers of Rock (sedimentary Rock Strata) Showed Evidence Of Gradual Change Over Time copyright cmassengale

33 33 Homologous Body Structures Scientists Noticed Animals With Backbones (Vertebrates) Had Similar Bone Structure Scientists Noticed Animals With Backbones (Vertebrates) Had Similar Bone Structure Similar structures in different organisms are from a Similar structures in different organisms are from a Common ancestor Common ancestor »Arms, Wings, Legs, Flippers copyright cmassengale

34 34 Homologous Structures copyright cmassengale

35 35 Similarities in DNA Sequence copyright cmassengale

36 36 Cytochrome c is a protein that is involved in cellular respiration in all eukaryotic organisms. Human cytochrome c contains 104 amino acids. The following table compares human cytochrome c with cytochrome c from a number of other organisms. OrganismNumber of cytochrome c amino acids that differ from human cytochrome c amino acids Chickens18 Chimpanzees0 Dogs13 Rattlesnakes20 Rhesus Monkey1 Yeasts56

37 37 Similarities In Early Development Embryonic Structures Of Different Species Show Significant Similarities Embryonic Structures Of Different Species Show Significant Similarities Embryo – 3 structures Embryo – 3 structures –Tail –Buds that become limbs –Pharyngeal pouches copyright cmassengale

38 38 Human Fetus – 5 weeks copyright cmassengale

39 39 ChickenTurtle Rat copyright cmassengale

40 Gradualism vs punctuated equilibrium Gradualism – gradual change over a long period of time lead to species formation Gradualism – gradual change over a long period of time lead to species formation Punctuated equilibrium- periods of rapid change in species are separated by periods of little or no change Punctuated equilibrium- periods of rapid change in species are separated by periods of little or no change copyright cmassengale40

41 Industrial Melanism copyright cmassengale41

42 Industrial melanism RA807djLc RA807djLc RA807djLc RA807djLc Hypothesis- dark peppered moths are camouflaged on the soot-darkened bark and so are not eaten by the birds. Light moths, on the other hand would stand out against the dark background and would be preyed upon. Hypothesis- dark peppered moths are camouflaged on the soot-darkened bark and so are not eaten by the birds. Light moths, on the other hand would stand out against the dark background and would be preyed upon. copyright cmassengale42


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