Evolution Notes BIOL 3303
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This 30 page Class Notes was uploaded by Madeline Abuelafiya on Saturday January 30, 2016. The Class Notes belongs to BIOL 3303 at Southern Methodist University taught by Dr. John Wise in Winter 2016. Since its upload, it has received 88 views. For similar materials see Evolution in Biology at Southern Methodist University.
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Date Created: 01/30/16
11:22 Welcome to Evolution 3303 “It is understandable when a child is afraid of the dark; not so, for a grown man to be frightened of the light” - Plato 1 Biol 3303 Evolution John Wise, Ph.D. • Office: DLS Room 234 • Tel.: 214-768-3426 • Email: email@example.com • Office hours: by appointment • Ask questions! • Come visit me 2 1 11:22 Biol 3303 Evolution The Course T-Th, 8:00 to 9:20 am, DLS 110 • Text: EVOLUTION – MAKING SENSE OF LIFE, 1st Edition by Carl Zimmer and Douglas J. Emlen Roberts and Company Publishers, Inc. Colorado, USA ISBN 978-1-936221-17-2 (hardcover) or ISBN 978-1-936221-36-3 (paperback) • Web pages – – PBS Evolution (a great web site) http://www.pbs.org/wgbh/evolution/ – http://courses.smu.edu – this course 3 Biol 3303 Evolution The Course • Grading: – 2 exams given (100 pts each) – Final (100 points) – Term paper (100 points) – Course grade equals sum of points (total of 400 pts possible) • My Powerpoint file outlines will usually be available on Blackboard 4 2 11:22 Biol 3303 Evolution Term Paper • Suggested topics in syllabus • You may write on your own topic, but you must get the topic “OK’d” by me • 1 page outline due on 3/1/16 • Paper due on 4/5/16 • You must follow the format requirements given in the syllabus (single-spaced, etc.) 5 Biological evolution • Any change in the inherited traits of a population that occurs from one generation to the next – “Descent with modification over generations” THE ORIGIN OF SPECIES (1859) C. Darwin – Driving force “Natural selection” • hereditary variations for those best adapted for reproduction 6 11:22 Evolution explains the diversity of life 7 Understanding evolution has practical implications How do pathogens become drug resistant? What is the source of new pathogens? 8 11:22 Evolution case studies • Whales: mammals gone to sea • Viruses: the deadly escape artists 9 How do we know whales are mammals? • Whales share many characteristics with mammals • Synapomorphies – traits that are “the same” or shared with common ancestors – Mammary glands – Three middle ear bones – Hair (in developing embryos) • Similarities with fish arose through convergent evolution – independent origin of similar traits in separate lineages 10 5 11:22 Fossil whales share synapomorphies with modern cetaceans http://www.pbs.org/wgbh/evolution/library/11/2/e_s_3.html Videos:PBS videos1 / evidenceforevolution/ EvolvingIdeas How Do We KnowEvolutionHappens_e_s_3_300.mov7min D:\Pbs_Videos_2\DeepTime_HistoryofLife\WhaleEvolution_l_034_05_300.mov5 min(startat 4:20) Fossils reveal links to land mammals • Shape of astragalus connects to artiodactyls 12 6 11:22 Fossil sequence documents transition from land to water 13 Documenting the transition from land to water Two types of very strong physical evidence • Isotopic analysis of fossil teeth • Fossil analysis of hindlimb loss Indohyus http://www.newscientist.com/article/dn13110-deerlike-fossil-is-a-missing-link-in- whale-evolution.html#.VLaApCvF_To 14 11:22 Isotopic analysis of fossil teeth • Terrestrial animals drink freshwater; marine animals drink saltwater 18 16 • O/ O ratio higher in saltwater – Higher ratio in teeth of marine animals 15 Fossils document hindlimb loss • Simplification of the pelvis 16 11:22 Changes in gene expression led to hindlimb loss • Hindlimbs begin to form but do not fully develop • Evolution of bodies – changes in development 17 Research gives more clues about whale evolution • Loss of teeth in baleen whales • Evolution of brain size and complexity • Whale diversity over evolutionary time http://www.scientificamerican.com/blog/post/are-whales18marter-than-we-are/?id=are-whales-smarter- than-we-are 11:22 Baleen whales lost teeth • Ancestors of all modern whales had teeth – Also produced small patches of baleen • Baleen completely replaced teeth in Mysticetes – Genes for building teeth disabled 19 Brain size and complexity the result of natural selection • Sociality promoted the evolution of large brains – Form lasting alliances – Competition for mates – Complex communication • Humans and whales – Cultural learning • Orca species teach hunting skills to young 20 11:22 Historical diversity tracks ecological changes to food web • More diatoms – more whale diversity? 21 Small populations put some cetaceans at risk of extinction 22 11:22 2009 H1N1 Flu Outbreak • Spread worldwide in a matter of weeks – First noticed in Mexico • 16,000 deaths in U.S. • Evolutionary biologists helped solve the mystery of its appearance 23 Flu life cycle 24 11:22 • Eight RNAs Vaccine design – 11 genes Part of flu vaccine; primes immune system5 antigenic sites on hemagglutinin 25 Why do new flu vaccines need to be made each year? • Mutations may be harmful or beneficial • Some mutations allow the virus to escape immune system memory cells 26 13 11:22 Viral strains with beneficial mutations increase in frequency through natural selection - Viral strain no longer recognized by immune system - Requires new vaccine 27 • Experiments with mice demonstrate viral evolution 28 14 11:22 Viral reassortment can lead to devastating consequences • Shuffling of the 8 RNAs – Can occur when one cell is infected by >1 virus – Rare • Immune system cannot recognize new surface proteins • New strains can cause significant mortality • Pandemic flus: – Spanish flu (1918) • 50-100 mio dead / 50% lethality – Asian Flu (1957-58) – Hong Kong Flu (1968-69) 29 The 2009 outbreak was the result of reassortment • Pig infected by bird, swine and human flu • New infection with Eurasian avian • New reassortment with Eurasian N1 New H1N1 flu 30 11:22 • Molecular clock suggests virus went undetected for months • May not have originated in Mexico 31 Evolution in the HIV system Four steps: 1. Reverse transcriptase errors produce variation in the HIV population (mutations). 2. Mutations are inherited by following virusesions of 3. treatment, some mutations (in RT) reproduce; others fail to reproduce. 4. With AZT present, RT mutations conferring resistance persist while sensitive strains die out 32 16 11:22 Another example: Multidrug-resistant tuberculosis http://www.pbs.org/wgbh/evolution/library/11/2/e_s_6.html • Now_e_s_6_300.mov 6.5 minvolution matters\Evolving Ideas Why Does Evolution Matter 33 Common misconceptions about evolution 34 17 11:22 Evolution is “just” a theory • Scientific theories backed by multiple lines of evidence – Provide overarching explanation for major aspects of natural world • Other scientific theories – Gravity – Plate tectonics – Germ theory • Evolutionary theory overwhelmingly accepted by scientists 35 Evolutionary biologists understand everything about the history of life • Not everything is known • Biologists continually discover new aspects of life – So far, all evidence fits within context of evolution 36 11:22 Evolution explains the origin of life • Evolution deals with how life has changed after it originated • Other scientific fields address the origin of life Google: – Prebiotic evolution – Origin of life research – Black smokers 37 Evolutionary biologists search for missing links • Biologists expect the fossil record to be incomplete – Finding direct ancestors is unlikely • Available evidence strongly supports relationships between current and past species – Relationships shed light on how traits evolved 38 11:22 Evolution violates the second law of thermodynamics • Holds that disorder increases in closed systems – Earth is not a closed system – Sun provides constant input of energy 39 Evolution is natural selection • Natural selection is a mechanism of evolutionary change • Other mechanisms: – Genetic drift – Sexual selection 40 11:22 Evolution is entirely random • Evolution includes random and non-random components – Mutations are random – Selection is the non-random spread of particular mutations • Convergent evolution demonstrates that evolution is non-random – Phenotypes are predictable when environments are similar 41 Organisms evolve adaptations they “need” • Evolution cannot identify needs – Mutations do not occur because they would be adaptive in an environment – If beneficial mutations happen to occur they may increase in frequency through selection 42 11:22 Evolution is a march of progress • Evolution is not ladder-like – New species result from branching events 43 Evolution always moves from simple to complex • Evolution can also move from complex to simple – e.g. mitochondria evolved from free-living bacteria – Tape worms have no digestive system 44 11:22 Evolution results from individuals adapting to environment • Evolution only works on inherited traits – Acquired changes are not passed to offspring • Populations evolve; individuals do not – Evolution results from changes in allele frequencies 45 Organisms are perfectly adapted to their environment • Natural selection can only work with available variation – Constrained by physics and development • Many traits involved in trade-offs – e.g. human brain size / birth canal size / jaw size 46 11:22 Evolution happens for the good of the species • Evolution selects traits that are beneficial for individuals or their genes – Traits that are bad for individuals (or genes) will not be selected even if they are good for the species 47 Evolution promotes selfishness and cruelty • Natural selection favors traits that increase reproductive success – Different conditions select for different traits – Cooperative traits are beneficial under some conditions 48 11:22 Evolution seeks peaceful harmony in nature • Natural selection favors traits that increase reproductive success – Can result in exploitation – Can result in cooperation 49 Life can be divided into higher and lower forms • All of life is adapted to the environment in numerous ways – Environments differ so adaptations differ – One adaptation is not “superior” to another adaptation 50 11:22 Evolution has produced a stable diversity of life • Extinction means diversity is not stable – 99% of all species that ever existed are extinct http://www.biologicaldiversity.o stainability/extinction_and_pop ulation_graph.html 51 One cannot be religious and scientific • Science and evolutionary theory are not mutually exclusive of religion. • A few examples follow 52 26 11:22 “I am a creationist and an evolutionist.” Theodosius Dobzhansky: “It is wrong to hold creation and evolution as mutually exclusive alternatives. I am a creationist and an evolutionist. Evolution is God's, or Nature's, method of Creation.” – from "Nothing in biology makes sense except in the light of evolution" (Am. Biol. Teach. 35, 125–129; 1973) Dobzhansky argued that "the Creator has created the living world not by caprice (supernatural fiat) but by evolution propelled by natural selection". 53 Accepting both God and Science Dr. Francis Collins is the director of the National Institutes of Health and is an evangelical Christian biologist. “the evidence that we are all descended from a common ancestor is overwhelming. Some might wish that not to be so. It is so. Does this conflict with Genesis 1 and 2? I don't believe it does.” 54 11:22 Francisco Ayala – Former Dominican Priest – Student of Theodosius Dobzhansky – Evolutionary Biologist and Philosopher at UC Irvine – National Academy of Science Member – >1000 publications! “Evolution is more consistent with belief in a personal god than intelligent design. If God has designed organisms, he has a lot to account for” – Sadism in parasites – 20% of pregnancies result in spontaneous abortion Don’t teach both evolution and creationism: – “We don’t teach alchemy along with chemistry. We don’t teach witchcraft along with medicine. We don’t teach astrology with astronomy.” 55 A Recommended Book on Evolution and Religion: FINDING DARWIN'S GOD: A SCIENTIST'S SEARCH FOR COMMON GROUND BETWEEN GOD AND EVOLUTION by Kenneth Miller – Professor of Biology Brown University http://www.brown.edu/Administration/Brown_Alumni_Magazine/00/11-99/features/darwin.html See also: http://www.millerandlevine.com/km/fdg/ 56 56 28 11:22 Rejecting God because of Science Dawkins argues that belief in a supernatural creator qualifies as a delusion. He has no more hard evidence that God does not exist than Intelligent Design has scientific evidence that God does exist. Each conclusion ultimately comes down a leap of faith. This leap takes you out of the natural world and science altogether and brings you into a matter of faith and belief. 57 Evolution and Religion: Is there a conflict? For more see http://ncseweb.org/media/voices/religion/ See also http://ncse.com/religion/science-religion-l58ks 11:22 Homework: What is Science? Information sheet to download on the Blackboard site – "What is Science.pdf". Please know this material. 59
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