Patterns in Nature (PDF)

What are we trying to explain? 1 This view of life: Patterns in Nature 1) Organisms seem to “fit” their environments 2) Nested variation – Groups within groups 2 1  Two patterns in Nature Hey!...

What are we trying to explain? 1 This view of life: Patterns in Nature 1) Organisms seem to “fit” their environments 2) Nested variation – Groups within groups 2 1  Two patterns in Nature Hey! Apparent “design” Nested variation What’s the Darwin explained both big idea!!! Design - the subject of the next set of lectures  Inheritance, Natural Selection Nested variation - Following 3 Pattern 1 - “Design” Organisms are complex 4 2  “Design” Organisms are functionally integrated 5 “Design” 6 3  Intelligent Design Natural Theology William Paley 1802 “the watch must have had a maker who comprehended its construction, and designed its use” 7 Intelligent Design Natural Theology This idea still around E.g. Behe, Dembski, etc. Complexity of cellular processes implies intelligent design 8 4  Intelligent Design Natural Theology This idea still around E.g. Behe, Dembski, etc. Complexity of cellular processes implies intelligent design 9 Intelligent Design Natural Theology This idea still around E.g. Behe, Dembski, etc. Complexity of cellular processes implies intelligent design Discovery Institute 10 5  Darwin and “Design” Natural Selection Variation Heritable variation Struggle Differentialreproduction based on heritable variation Changes in characteristics of the population - evolution 11 Darwin and “Design” Natural Selection – Much more to come Leads to adaptation Explains apparent design 12 6  Adaptations vs. Good fit Notall useful features are adaptations for that use. 13 Adaptations vs. Good fit Notall useful features are adaptations for that use. 14 7  Does Natural selection produce perfect adaptations? NO History At best, natural selection is one generation behind Organisms have a history Evolution must tinker with pre-existing “designs” 15 Does Natural selection produce perfect adaptations? NO History Constraint Some great ideas never appear 16 8  Does Natural selection produce perfect adaptations? NO History Constraint Compromise " Ideal design is a lousy argument for evolution...Odd arrangements and funny solutions are proof of evolution.” S. J. Gould 17 Adaptation and Convergence Similar circumstances can lead to similar adaptations independently This is called convergence Convergent characters are said to be analogous Convergence is common 18 9  Adaptation and Convergence 19 Adaptation and Convergence 20 10  Adaptation and Convergence 21 22 11  Nested Variation: Groups nested within Groups Formsthe basis for “God creates, Linnaeus disposes” Linnaean classification Non-evolutionary Groups within Groups 23 Kingdom Animalia Phylum Chordata Class Mammalia Order Primates Family Hominidae 24 12  Groups nested within Groups Darwin explained this pattern very nicely Phylogenetic Tree Patterns within patterns can be explained by recency of shared ancestry! 25 Groups nested within Groups Darwin explained this pattern very nicely Phylogenetic Tree Patterns within patterns can be explained by recency of shared ancestry! 26 13  Groups nested within Groups Darwin explained this pattern very nicely Phylogenetic Tree Patterns within patterns can be explained by recency of shared ancestry! 27 Groups nested within Groups Darwin explained this pattern very nicely Phylogenetic Tree Patterns within patterns can be explained by recency of shared ancestry! 28 14 29 Homology Similarities inherited from a common ancestor are called homologous Fig. 22.15 30 15  Homology vs. Analogy Similarities inherited from a common ancestor are called homologous 31 Homology vs. Analogy Similarities inherited from a common ancestor are called homologous Similarities that are independently evolved are called analogous (or convergent) 32 16  Homology vs. Analogy. Eyes evolved many times, including here and here Platyhelminthes Echinodermata Hemichordata Onychophora Brachiopoda Ctenophora Arthropoda Ectoprocta Nematoda Chordata Mollusca Annelida Cnidaria Porifera Rotifera 33 Summary Patternsare apparent in Nature Organisms are complex, “fit” their environment Design (e.g. a watch) vs. Natural Selection Adaptations arise via Natural selection Not all useful features are adaptations Naturalselection cannot produce perfection History, Constraint, Compromise Convergence is common (analogous structures) 34 17  Summary Groups within groups The basis for Linnean classification Nested groups are branches of the Tree of Life Homologous structures are found in a common ancestor Evolution is a tinkerer, not an engineer 35 Evidence For evolution 36 18  Darwin neatly explained Hey! two patterns in Nature What’s the Apparent “design” Nested variation big idea!!! Darwinhad two major accomplishments 1)Establishedevolution 2)Proposed mechanism for apparent design Strength of support for 1 37 What makes a scientific theory strong? 38 19  Two models in the early 19th century Separate creation vs. Community of descent What would each predict for … Yellow: Presence of nested variation Blue: Presence of nonfunctional features Green: Complexity of older vs. recent life Purple: Presence of intermediate forms 39 Prevailing views before 1800 Species constant The Greeks  Variation not important  Is just imperfection  Influenced by geometry 40 20  Prevailing views before 1800 Species constant The Greeks  Variation not important  Is just imperfection Cuvier and his Ibises  1769-1832  Believed in functional integration  Saw no evidence of change 41 Prevailing views before 1800 Species constant No extinction Young Earth  E.g.6000 years old  Catastrophism Natural Theology  Argument from Design 42 21  Changing World Views Constancy of species Lamarck (and others)  1744-1829  Explicit about evolution “… aided by much time and by a slow but constant diversity of circumstances, [Nature] has gradually brought about in this respect the state of things which we now observe. How grand is this consideration, and especially how remote it is from all that is generally thought on the subject!” Lamarck, 1803 43 Changing World Views Constancy of species Extinction Cuvier  Not an evolutionist, but...  Established extinction as a fact 44 22  Changing World Views Constancy of species Extinction Age of the Earth Hutton and Lyell Uniformitarianism and an old Earth Planted idea of gradual change over long periods of time “ Present as the key to the past” 45 Changing World Views Constancy of species Extinction Age of the Earth Hutton and Lyell Uniformitarianism and an old Earth Planted idea of gradual change over long periods of time 46 23  Changing World Views Constancy of species Extinction Age of the Earth Natural Theology Lamarck  Evolution could explain many curious facts (e.g. fossils, development, vestigial organs)  Darwin, Wallace  And the appearance of design! 47 Darwin’s Accomplishments Established evolution  An old idea, but Darwin provided overwhelming evidence and a very clear argument  Widely accepted after 1859 Proposed a plausible mechanism for evolutionary change and design  Huxley - “How stupid of me not to have thought of that”  Not widely accepted at first We will explore both of these topics in detail 48 24  Yellow: Predictions of Separate Creation vs. Descent with Modification 1. No Nesting vs. Nesting 2. No specific prediction vs. Nesting 3. Nesting vs. Nesting 4. Nesting vs. No Nesting 5. No specific prediction for either 49 Blue: Predictions of Separate Creation vs. Descent with Modification 1. All functional vs. Some vestigial 2. Both predict some would be vestigial 3. Both predict all would be functional 4. No specific prediction for either 50 25  Green: Predictions of Separate Creation vs. Descent with Modification 1. Both models suggest original complexity 2. Original complexity vs. simple first, complex later 3. Simple first, complex later vs. original complexity 4. Both models suggest simple first, complex later 51 Purple: Predictions of Separate Creation vs. Descent with Modification 1. Neither predicts intermediates 2. No intermediates vs. Intermediates present 3. Both predict intermediates 4. No specific prediction for either 52 26  Evidence For Evolution “Groups within Groups” Noprior explanation - God’s plan Make sense as a result of community of descent 53 Evidence For Evolution Homology (a related idea)  Structural similarities under different uses more easily explained by community of descent than design  E.g. morphology, developmental patterns, genes Fig. 24.9 54 27  Evidence For Evolution Homology (a related idea)  Structural similarities under different uses more easily explained by community of descent than design  E.g. morphology, developmental patterns, genes Fig. 24.8 55 Evidence For Evolution Vestigial Structures E.g. Goose bumps 56 28  Evidence For Evolution Vestigial Structures E.g. Goose bumps 57 Evidence For Evolution Vestigial Structures Show evidence of past function, but no longer used Strong evidence against intelligent design Make sense in terms of evolutionary history Tinkering with pre-existing “ designs” 58 29  Evidence For Evolution Vestigial Structures E.g. Whale teeth Whale pelvis 59 Evidence For Evolution Vestigial Structures E.g. Whale teeth Whale pelvis Cave organisms 60 30  Evidence For Evolution Vestigial Structures E.g. Whale teeth Whale pelvis Cave organisms Vestigial wings 61 Evidence For Evolution Vestigial Structures E.g. Whale teeth Whale pelvis Cave organisms Vestigial wings Pseudogenes See pp. 368 62 31  Evidence For Evolution Vestigial Structures E.g. Whale teeth Whale pelvis Cave organisms Vestigial wings Pseudogenes “Lesbian” lizards 63 Evidence For Evolution Fossil record Earth is old (as measured by various methods) Extinction has occurred General pattern  Simpler organisms first, then more complex  No “ Fossil rabbits in the Precambrian” 64 32 Evidence For Evolution Fossil record Earth is old (as measured by various methods) Extinction has occurred General pattern  Simpler organisms first, then more complex  No “ Fossil rabbits in the Precambrian” See Fig. 27.8 65 Evidence For Evolution Fossil record Earth is old (as measured by various methods) Extinction has occurred General pattern Law of Succession  Living species usually preceded by similar fossil forms in the same area  E.g. Marsupials 66 33  Evidence For Evolution Fossil record Earth is old (as measured by various methods) Extinction has occurred General pattern Law of Succession Transitional forms  Linking closely related species - Humans 67 Evidence For Evolution 68 34  Evidence For Evolution Fossil record Earth is old (as measured by various methods) Extinction has occurred General pattern Law of Succession Transitional forms  Linking closely related species - Humans  Documenting major transitions - Origin of whales 69 Evidence For Evolution "Darwinists rarely mention the whale because it presents them with one of their most insoluble problems.... A land mammal that was in the process of becoming a whale would fall between two stools. It would not be fitted for life on land or at sea, and would have no hope for survival.” Haywood, 1985, Creation and Evolution 70 35  Evidence For Evolution 71 Evidence For Evolution Fossil record Earth is old (as measured by various methods) Extinction has occurred General pattern Law of Succession Transitional forms - Mosaics and intermediates  Linking closely related species - Humans  Documenting major transitions - Origin of whales  Linking major groups - origin of birds, mammals 72 36  Evidence For Evolution 73 Evidence For Evolution 74 37  Evidence For Evolution Biogeography Small scale E.g.  Cave organisms usually related to nearby non- cave organisms, rather than cave dwellers in other parts of the world 75 Evidence For Evolution Biogeography Small scale E.g.  Galapagos finches related to South American birds of very different habits and appearance 76 38  Evidence For Evolution Biogeography Small scale Larger scale Communities may be similar, flora and fauna differ  E.g. placental/marsupial 77 Evidence For Evolution Biogeography Small scale Larger scale Huge scale - fauna show history of continental drift  Wegener  E.g. Close relationship of fossil and living organisms on Africa, South America 78 39  Evidence For Evolution Biogeography Small scale Larger scale Huge scale - fauna show history of continental drift  Wegener  E.g. Close relationship of fossil and living organisms See Fig. 27.10 on Africa, South America 79 Evidence For Evolution 80 40  Evidence For Evolution RIP 81 Remember … what are we trying to explain? http://biology.stackexchange.com/questions/34521/is-batesian-mimicry-more-important-for-females 82 41  Evidence For Evolution Direct observation or strong inference of evolutionary change  Evolution of disease resistance  Finches See Fig. 24.17 83 Evidence For Evolution Direct observation or strong inference of evolutionary change  Evolution of disease resistance  Finches  Artificial breeding 84 42  Evidence For Evolution 85 Evidence For Evolution Direct observation or strong inference of evolutionary change  Evolution of disease resistance  Finches  Artificial breeding 86 43  Summary Evolution is a testable hypothesis Evolution is supported by a vast array of independent types of data  Comparative anatomy, genetics  Development  Vestigial organs  Fossils  Biogeography, Geology  Observation and strong inference 87 44