Chapter 15 Evolution. Think About It? What is evolution? What is evolution? Why does it happen? Why does it happen? How does it happen? How does it happen?

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Slide 1Chapter 15 Evolution Slide 2 Think About It? What is evolution? What is evolution? Why does it happen? Why does it happen? How does it happen? How does it happen? Slide 3 What is evolution? Change in a population over time Change in a population over time at genetic level at genetic level mutations mutations Slide 4 Mutations Change in DNA code Change in DNA code can affect phenotype can affect phenotype Slide 5 REVIEW: From Gene to Protein Slide 6 The Darwin Dude 5 year voyage on Beagle (1831-36) 5 year voyage on Beagle (1831-36) Naturalist: surveyed coast of S.A. Naturalist: surveyed coast of S.A. Wrote Origin of Species Wrote Origin of Species Slide 7 Collected: Collected: Rocks Fossils Plants Animals Charles Lyells Principles of Geology proposed Earth was millions of years old! Charles Lyells Principles of Geology proposed Earth was millions of years old! The Darwin Dude Slide 8 Explained marine life at high elevation in the Andes Explained marine life at high elevation in the Andes Giant fossil versions of smaller living mammals Giant fossil versions of smaller living mammals Earthquakes could lift rocks great distances very quickly. Earthquakes could lift rocks great distances very quickly. Lyell: Slide 9 Galapagos Island Facts Part of Ecuador Part of Ecuador 13 main volcanic islands 13 main volcanic islands Formed between 5 - 10 MYA Formed between 5 - 10 MYA Slide 10 Darwin & Galapagos Organisms adapted to their environment Organisms adapted to their environment Darwins Finches Darwins Finches Gould (ornithologist) finches were separate species not found any where else. Mechanism for evolution = Natural Selection Mechanism for evolution = Natural Selection Slide 11 Darwin believed new species appear gradually through small changes in ancestral species. Darwin believed new species appear gradually through small changes in ancestral species. Breeders can promote specific traits by selecting and breeding organisms that have the most exaggerated expressions of those traits. Breeders can promote specific traits by selecting and breeding organisms that have the most exaggerated expressions of those traits. Known as Artificial Selection! Artificial Selection: Slide 12 If humans could change species by artificial selection, the same process could work in nature! If humans could change species by artificial selection, the same process could work in nature! Given enough time this process could produce new species ! Given enough time this process could produce new species ! Inference: Slide 13 Artificial Selection: Slide 14 Noteworthy Species Slide 15 Darwins Finches Adaptive Morphology Slide 16 Why do species change? Variations & adaptations help organisms survive Variations & adaptations help organisms survive Slide 17 Slide 18 Camouflage Slide 19 Slide 20 Human population, if unchecked, would eventually outgrow its food supply, leading to a competitive struggle for existence. Human population, if unchecked, would eventually outgrow its food supply, leading to a competitive struggle for existence. Darwin believed Malthuss ideas could be applied to the natural world. Darwin believed Malthuss ideas could be applied to the natural world. Some competitors are better equipped for survival than others! Thomas Malthus: Slide 21 Natural Selection Organisms with favorable traits survive & reproduce Organisms with favorable traits survive & reproduce Variation is key Variation is key Slide 22 Natural Selection (cont.) Struggle for existence Struggle for existence Species become better fit for their environment Species become better fit for their environment If not they could DIE! If not they could DIE! Slide 23 Natural Selection (cont.) 4 Main Principles (pg 421): 1. Variation 2. Heritability 3. Overproduction 4. Reproductive Advantage Slide 24 Individuals in a population differ from one another. Individuals in a population differ from one another.Example: 1. Variation: Slide 25 2. Heritability: Variations are inherited from parents. Variations are inherited from parents.Example: X Slide 26 3. Overproduction: Populations produce more offspring than can survive. Populations produce more offspring than can survive.Example: 48 white tiger litters produces 148 cubs 105 of them died without reproducing71% Slide 27 4. Reproductive Advantage: Some variations allow the organism that possesses them to have more offspring than the organism that does not possess them. Some variations allow the organism that possesses them to have more offspring than the organism that does not possess them.Example: White tigers have powerful jaws & teeth, very strong sense of smell, sharp eyesight, and excellent swimmers! Slide 28 Slide 29 Types of Natural Selection 1. Stabilizing Selection: Average phenotype favored Ex. Human baby weight Slide 30 Stabilizing Selection Slide 31 Types of Natural Selection 2. Directional Selection: increases extreme versions of traits Ex. Peppered Moth, Darwins finches Slide 32 Peppered Moth: Natural Selection Slide 33 Directional Selection Slide 34 Types of Natural Selection 3. Disruptive Selection: splits populations into 2 groups Both extremes favored Both extremes favored Ex. Marine & Land Iguanas Ex. Marine & Land Iguanas Slide 35 Disruptive Selection Slide 36 V = Variation: All life forms vary genetically within a population. It is this genetic variation upon which selection works. I = Inheritance: Genetic traits are inherited from parents and are passed on to offspring. S = Selection: Organisms with traits that are favorable to their survival get to live and pass on their genes to the next generation. T = Time: Evolution takes time. Evolution can happen in a few generations, but major change, such as speciation, often takes long periods of time. Slide 37 Evidence of Evolution 1. Fossil Record Fossils: preserved evidence Fossils: preserved evidence Found in Sedimentary rock Found in Sedimentary rock Slide 38 Provides record of species that lived long ago. Provides record of species that lived long ago. Some similar to current ones! Some similar to current ones! Some species unchanged! Some species unchanged! Evidence of Evolution Slide 39 Similar fossil forms: Glyptodon & Glyptodon &Armadillos Slide 40 Species unchanged: Horseshoe Crab! Horseshoe Crab! Slide 41 Fossil Record (cont) A. Soft parts dont fossilize B. Specific conditions are needed to form fossils C. Hundreds of transitional fossils found Slide 42 Slide 43 Classes of Traits: Two major classes of traits while studying transitional fossils: Two major classes of traits while studying transitional fossils: Derived traits: newly evolved features Ancestral traits: more primitive features that appear in ancestor forms. Slide 44 2. Homologous Structures: Anatomically similar structures Anatomically similar structures Evidence of common evolutionary origin Evidence of common evolutionary origin Evidence of Evolution Slide 45 Homologous Structures Slide 46 Slide 47 Slide 48 Slide 49 Analogous Structures: Can be used for same purpose and can be superficially similar in construction but are not inherited from a common ancestor. Can be used for same purpose and can be superficially similar in construction but are not inherited from a common ancestor. Slide 50 Analogous Structures: Slide 51 3.Embryology: similarities in embryos similarities in embryos Evidence of Evolution Slide 52 Embryology: Embryo early, pre-birth stage of an organisms development. Embryo early, pre-birth stage of an organisms development. Vertebrate embryos exhibit homologous structures during certain phases of development. Vertebrate embryos exhibit homologous structures during certain phases of development. Slide 53 Slide 54 4.Compararative Biochemistry: Organisms have similar DNA, genes and enzymes Evidence of Evolution Slide 55 Slide 56 Comparative Biochemistry: The more closely related the species are, the greater number of amino acid sequences they will share. The more closely related the species are, the greater number of amino acid sequences they will share. Ex. Chimpanzees and Humans share 96% similar sequences! Slide 57 Humans & Chimpanzees: Human genome is 96% similar to great ape species. Human genome is 96% similar to great ape species. Pan troglodytes (species of chimp) used in study Pan troglodytes (species of chimp) used in study The number of genetic differences between humans and chimps is ten times smaller than that between mice and rats. Slide 58 Pan troglodytes (common Chimp) Slide 59 5. Vestigial Structures: reduced in size, no longer have function reduced in size, no longer have function Evidence of Evolution Slide 60 Slide 61 Formation of new species Formation of new species Become genetically different Become genetically different What is Speciation? Slide 62 What are Species? Group of organisms that can interbreed & produce fertile offspring Group of organisms that can interbreed & produce fertile offspring Slide 63 Infertile Species Horse + Donkey = Mule 64 ch. + 62 ch. = sterile Slide 64 Liger http://www.youtube.com/watch?v=WdTl n4QwexQ&feature=related Slide 65 Species Loop Hole Not a perfect definition Not a perfect definition Used for classification Used for classification Some different species can produce fertile offspring Some different species can produce fertile offspring Slide 66 Grizzly Bear & Polar Bear Pizzly or Grolar Pizzly or Grolar Slide 67 Rate of Speciation Gradualism: Evolution occurring at slow rate Gradualism: Evolution occurring at slow rate Punctuated Equilibrium: Evolution occurring at irregular rates Punctuated Equilibrium: Evolution occurring at irregular rates Slide 68 Slide 69 Cause of Speciation 1. Geographic Barriers Mountains, Rivers, etc. Mountains, Rivers, etc. 2. Environment Changes Slide 70 3. Reproductive Isolation Examples: Examples: mating at different times birds mating with others who sing a particular song. Cause of Speciation Slide 71 1. Adaptive radiation (divergent evolution) 2. Coevolution 3. Convergent evolution Patterns of Evolution: Slide 72 Relatively short period of time Relatively short period of time 1 species gives rise to many 1 species gives rise to many Usually occurs after mass extinctions Usually occurs after mass extinctions 1. Adaptive Radiation: Slide 73 Evolution of 1 species affects the evolution of another species. Evolution of 1 species affects the evolution of another species. 2. Coevolution: Slide 74 Unrelated species evolve similar traits Unrelated species evolve similar traits Under same environmental Under same environmental pressures pressures 3. Convergent Evolution:

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