1 Evolution Diversity of Life copyright cmassengale

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

3 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

4 Lamarck’s Theory of Evolution Inheritance of Acquired Characteristics Inheritance of Acquired Characteristics Proposed That By Selective Use Or Disuse Of Organs, Organisms Acquired Or Lost Certain Traits During Their Lifetime Proposed That By Selective Use Or Disuse Of Organs, Organisms Acquired Or Lost Certain Traits During Their Lifetime These Traits Could Then Be Passed On To Their Offspring These Traits Could Then Be Passed On To Their Offspring Over Time This Led To New Species Over Time This Led To New Species copyright cmassengale

5 Lamarck’s Theory of Evolution Use & Disuse - Organisms Could Change The Size Or Shape Of Organs By Using Them Or Not Using Them Use & Disuse - Organisms Could Change The Size Or Shape Of Organs By Using Them Or Not Using Them Blacksmiths & Their Sons (muscular arms) Blacksmiths & Their Sons (muscular arms) Giraffe’s Necks Longer from stretching) Giraffe’s Necks Longer from stretching) copyright cmassengale

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7 Lamarck’s Mistakes Lamarck Did NOT Know how traits were inherited (Traits are passed through genes) Lamarck Did NOT Know how traits were inherited (Traits are passed through genes) Genes Are NOT Changed By Activities In Life Genes Are NOT Changed By Activities In Life Change Through Mutation Occurs Before An Organism Is Born Change Through Mutation Occurs Before An Organism Is Born copyright cmassengale

8 Charles Darwin the Naturalist copyright cmassengale

9 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 Astounded By Variety of Life Astounded By Variety of Life copyright cmassengale

10 A reconstruction of the HMS Beagle sailing off Patagonia. Darwin’s Voyage of Discovery copyright cmassengale

11 The Galapagos Islands Small Group of Islands 1000 km West of South America Small Group of Islands 1000 km West of South America Very Different Climates Very Different Climates Animals On Islands Unique Animals On Islands Unique »Tortoises »Iguanas »Finches copyright cmassengale

12 The Galapagos Islands Volcanic islands off the coast of South America Volcanic islands off the coast of South America Island species varied from mainland species & from island-to- island species Island species varied from mainland species & from island-to- island species Each island had long or short neck tortoises Each island had long or short neck tortoises copyright cmassengale

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14 The Galapagos Islands Finches on the islands resembled a mainland finch Finches on the islands resembled a mainland finch 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

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16 Darwin’s Observations & Conclusions Developing the Theory of Evolution copyright cmassengale

17 Darwin’s Observations Patterns of Diversity were shown Patterns of Diversity were shown Unique Adaptations in organisms Unique Adaptations in organisms Species Not Evenly Distributed Species Not Evenly Distributed »Australia, Kangaroos, but No Rabbits »S. America, Llamas copyright cmassengale

18 Darwin’s Observations Both Living Organisms & Fossils collected Both Living Organisms & Fossils collected Fossils included: Fossils included: »Trilobites »Giant Ground Sloth of South America This species NO longer existed. What had happened to them? copyright cmassengale

19 Evidence for Evolution – The Fossil Record copyright cmassengale

20 Definition Evolution is the slow, gradual change in a population of organisms over time copyright cmassengale

21 Darwin’s Observations Left unchecked, the number of organisms of each species will increase exponentially, generation to generation In nature, populations tend to remain stable in size Environmental resources are limited copyright cmassengale

22 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

23 Darwin’s Observations Individuals of a population vary extensively in their characteristics with no two individuals being exactly alike. Much of this variation between individuals is inheritable. copyright cmassengale

24 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

25 The unequal ability of individuals to survive and reproduce leads to a gradual change in a population, with favorable characteristics accumulating over generations (natural selection)The unequal ability of individuals to survive and reproduce leads to a gradual change in a population, with favorable characteristics accumulating over generations (natural selection) New species evolveNew species evolve Darwin’s Theory of Evolution copyright cmassengale

26 Population Growth Darwin Realized Plants & Animals Produce Far More Offspring Than Can Be Supported Darwin Realized Plants & Animals Produce Far More Offspring Than Can Be Supported –Most Die –If They Didn’t – Earth Would Be Overrun copyright cmassengale

27 Natural Variation and Artificial Selection Natural Variation Natural Variation –Differences Among Individuals Of A Species Artificial Selection Artificial Selection –Selective Breeding To Enhance Desired Traits Among Stock or Crops copyright cmassengale

28 Natural Variation and Artificial Selection Key Concept: In Artificial Selection, Nature Provided The Variation Among Different Organisms, And Humans Selected Those Variations That They Found Useful copyright cmassengale

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30 Origin of Species Concepts and Controversy copyright cmassengale

31 Evolution By Natural Selection Concepts The Struggle for Existence (compete for food, mates, space, water, etc.) The Struggle for Existence (compete for food, mates, space, water, etc.) Survival of the Fittest (strongest able to survive and reproduce) Survival of the Fittest (strongest able to survive and reproduce) Descent with Modification (new species arise from common ancestor replacing less fit species) Descent with Modification (new species arise from common ancestor replacing less fit species) copyright cmassengale

32 Survival of the Fittest Fitness –Ability of an Individual To Survive & Reproduce Adaptation –Inherited Characteristic That Increases an Organisms Chance for Survival copyright cmassengale

33 Survival of the Fittest Adaptations Can Be: – –Physical »Speed, Claws, Quills, etc. »Mimicry and Camouflage –Behavioral »Solitary, Herds, Packs, Activity, etc. copyright cmassengale

34 Survival of the Fittest Is Central To The Process Of Evolution Fitness Is Central To The Process Of Evolution Individuals With Low Fitness Individuals With Low Fitness –Die –Produce Few Offspring Survival of the Fittest AKA AKA Natural Selection copyright cmassengale

35 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

36 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

37 Descent With Modification Takes Place Over of Time Takes Place Over Long Periods of Time Natural Selection Can Be As Changes In Natural Selection Can Be Observed As Changes In –Body Structures –Ecological Niches –Habitats copyright cmassengale

38 Descent With Modification Species From Their Ancestors Species Today Look Different From Their Ancestors Each Living Species Has Each Living Species Has –Descended –With Changes –From Other Species –Over Time copyright cmassengale

39 Descent With Modification copyright cmassengale

40 Descent With Modification Implies Implies –All Living Organisms Are Related –Single Tree of Life »DNA, Body Structures, Energy Sources Common Descent –All Species, Living & Extinct, Were Derived From Common Ancestors copyright cmassengale

41 Theory of Evolution Today Supporting Evidence copyright cmassengale

42 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 –The Geographical Distribution of Living Species –Similarities In Early Development copyright cmassengale

43 Fossil Record Earth is Billions of Years Old Earth is Billions of Years Old 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

44 Homologous Body Structures Scientists Noticed Animals With Backbones (Vertebrates) Had Similar Bone Structure Scientists Noticed Animals With Backbones (Vertebrates) Had Similar Bone Structure May Differ In Form or Function May Differ In Form or Function Limb Bones Develop In Similar Patterns Limb Bones Develop In Similar Patterns »Arms, Wings, Legs, Flippers copyright cmassengale

45 Homologous Structures copyright cmassengale

46 Homologous Body Structures Not All Serve Important Functions Not All Serve Important Functions –Vestigial Organs »Appendix In Man »Legs On Skinks –Analogous Structures »Can be used for same purpose but are not inherited from common ancestor »Wing of an eagle and wing of a beetle copyright cmassengale

47 Similarities In Early Development Embryonic Structures Of Different Species Show Significant Similarities Embryonic Structures Of Different Species Show Significant Similarities Embryo – early stages of vertebrate development Embryo – early stages of vertebrate development copyright cmassengale

48 Evidence for Evolution - Comparative Embryology Similarities In Embryonic Development copyright cmassengale

49 Human Fetus – 5 weeks copyright cmassengale

50 ChickenTurtle Rat copyright cmassengale

51 The End copyright cmassengale