week 8 notes
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This 10 page Class Notes was uploaded by Katelyn Scott on Friday September 11, 2015. The Class Notes belongs to BIOL-L 105 at Indiana University taught by T.J. Sullivan in Summer 2015. Since its upload, it has received 15 views. For similar materials see Introduction to Biology in Biology at Indiana University.
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Date Created: 09/11/15
Ch 24 Evolution by natural selection 102414 102414 4 What is evolution IThe process that explains the patterns we see in the natural world IUnifying theory of biology 1 What is a theory I Defines a large group of observations I Makes predictions I unprovable but falsifiable 102414 4 Scientific theories I The formal scientific definition of theory is quite different from the everyday meaning of the word It refers to a comprehensive explanation of some aspect of nature that is supported by a vast body of evidence Many scientific theories are so well established that no new evidence is likely to alter them substantially For example no new evidence will demonstrate that the Earth does not orbit around the sun heliocentric theory or that living things are not made of cells cell theory that matter is not composed of atoms or that the surface of the Earth is not divided into solid plates that have moved over geological timescales the theory of plate tectonics One of the most useful properties of scientific theories is that they can be used to make predictions about natural events or phenomena that have not yet been observedquot National Academy of Science 102414 4 What is evolution I Important predictions Species are not static over time 4 2 Species are related not independent 102414 102414 Process of evolution I How can we measure change over time generation to generation I Genetic changes over time Population level measurement not individual Individuals don t evolve populations do I Population Interbreeding group of individuals 102414 Example with kitties 102414 Example with kitties 102414 History of evolutionary thought Aristotle and others proposed that species u were organized into a Humans sequence based on increased size and complexity with Livebearing humans at the top vertebrates L Eggbearing vertebrates 4K Invertebrates Higher plants Lower plants lnanimate atter 3939362 I Hierarchy of living things I Species and the living world are static 102414 102414 H History of evolutionary thought 102414 13 H L US History of evolutionary thought I Jean Baptiste de Lamarck 1809 I Species change over time due the inheritance of shared characteristics 102414 H E j H History of evolutionary thought I Jean Baptiste de Lamarck 1809 I Species change over time due the inheritance of shared characteristics 102414 H E j H Growing evidence from geology a 180millionyearold I Lots of fossil gathering by the mid1800s I Sedimentary and volcanic rocks are formed in layers I Fossils could be organized by age 102414 Growing evidence from geology I Fossils probably weren t just from species that hadn t been discovered yet I 99 of all species are extinct now 102414 102414 Growing evidence from geology IAs more fossils were found more transitional forms were discovered J1 xsr w Eusthenopteron 385 mya l 17 102414 Vestigial traits a The human tailbone is a vestigial trait b Goose bum r lt vestigial trait tail used 39 for balance and locomotion Human coccyx IVestigial traits reduced or incompletely developed structure Human goose bump mo aaaaaaaaaaaaaaaa llnc lEvidence for relatedness 102414 Vestigial traits lWings on ostriches amp kiwis lMuscles to your ears IPelvic structures on boas and pythons lEyes on cave dwelling species IPseudogenes L gulonolactone oxidase 102414 102414 Homology ILiving things share many many things in common I Genetic homology Gene Amino acid sequence singleletter abbreviations Aniridia Human LORNRTSFTGEQIEALEKEFERTHYPDVFARERLAAKIDLPEARIQVWFSNRRAKWRREE eyeless Fruit fly LQRNRTSFTNDQIDSLEKEFERTHYPDVFARERLAGKIGLPEARIQVWFSNRRAKWRREE Only six of the 60 amino acids in these sequences are different The two sequences are 90 identical mu mam Education Inc 102414 Genetic homology I Can move genes between species and they ll still work Fly leg I Mouse gene for eye formation in Drosophila 102414 Structural homology i Humerus Radius and ulna Carpals Metacarpals Phalanges Turtle Human Horse Bird Seal mm P 102414 Developmental homology Gill pouch Gill pouch Gill pouch hick House cat mom Pearson Educauon m 102414 How we use homology ITesting drugs in nonhuman organisms ITesting toxins in nonhuman organisms IIdentifying unknown sequences 102414 102414 TABLE 241 Evidence for Evolution Prediction 1 Species Are Not Static but Change through Time 0 Most species have gone extinct 0 Fossil extinct species frequently resemble living species found in the same area 0 Transitional features document change in traits through time o Vestigial traits are common The characteristics of populations can be observed changingtoday Prediction 2 Species Are Related Not Independent 0 Closely related species often live in the same geographic area Homologous traits are common and are recognized at three levels 1 genetic gene structure and the genetic code 2 developmental embryonic structures and processes 3 structural morphologicaltraits in adults The formation of new species from preexisting species can be observed today Process of evolution I How can we measure change over time generation to generation I Genetic changes over time Population level measurement not individual Individuals don t evolve populations do I Population Interbreeding group of individuals 102414 102414 27 Darwin s theory a natural selection 1 There is variation between individuals 2 Some of this variation is heritable 102414 102414 Darwin s theory of natural selection 3 More offspring are born than can be supported generation Not all offspring will reproduce themselves 102414 Are more offspring born than can be supported Elephants 19 million in 750 years Aphis fabae an aphid houseflies Mycophila speyeri a fly Staphylococcus aureus Starfish 102414 Darwin s theory of natural selection I Start with 2 African elephants They have 4 offspring total Probably 6 offspring total I Generation time 25 years I How many elephants after 30 generations 750 years 102414 Darwin s theory of natural selection I After 1 generation 4 elephants I After 10 generations 2048 elephants I After 30 generations 2147483648 elephants 102414 q Darwin s theory of natural selection I How many African elephants are on Earth 700000 100 years ago 3 5 million 102414 102414 4 Are more offspring born than can be supported Elephants 19 million in 750 years Aphis fabae an aphid 524 billion in 1 year houseflies Mycophila speyeri a fly Staphylococcus aureus Starfish 102414 a Are more offspring born than can be supported Elephants 19 million in 750 years Aphis fabae an aphid 524 billion in 1 year houseflies 191 x 1018 in 5 months Mycophila speyeri a fly 20000 square foot in 35 days Staphylococcus aureus Starfish 102414 4 Are more offspring born than can be supported Elephants 19 million in 750 years Aphis fabae an aphid 524 billion in 1 year houseflies 191 x1018 in 5 months Mycophila speyeri a fly 20000 square foot in 35 days Staphylococcus aureus Layer over the Earth 7 feet deep in 48 hours Starfish 102414 Are more offspring born than can be suppo ed Elephants 19 million in 750 years Aphis fabae an aphid 524 billion in 1 year houseflies 191 x 1018 in 5 months Mycophila speyeri a fly 20000 square foot in 35 days Staphylococcus aureus Layer over the Earth 7 feet deep in 48 hours Starfish 1079 in 16 years 102414 102414 Darwin s theory of natural selection 3 More offspring are born than can be supported generation 4 Some individuals have a higher chance of survival and reproduction than others pass on these traits to their offspring fitness 102414 What is required for natural selection IHeritable genetic variation I Environmental variation IUnequal reproductive success related to the genetic variation I Natural selection requires interaction with the environment 102414 Adaptations IAdaptation Modification in structure function or behavior that provides an advantage in the Lient environment White fur is a great trait in the arctic but terrible in the tropics IReproductive success depends on interaction between your genotype and the present environment I Bunny time 102414 102414 How does evolution impact my life 102414 4 Public health 102414 q Evolutionary biology Antigenic drift IF Fitch W M at al PNAS19979477127718 Ional Academy of Sclences of the USA 102414 10
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