9/27/2012
History of Evolutionary Thought Epistemology and Evolution • Argument from Authority – Reality can be explained by scripture or by persons • Methodological Naturalism – Nature to explain nature – Supernatural explanations are not allowed
Aristotle (384-322 B.C.E.) Rise and Fall: in a nutshell Plato’s student Studied ecology, biology, and geology • Greeks used methodological naturalism Continued Plato’s idea of eidos Concept of eidos for species persisted until • After, Aristotle and scripture used for Darwin
knowledge • Methodological naturalism rejected – not entirely • 18th century: Age of Enlightenment – Search for laws
Age of the Earth Charles Lyell (1797-1875)
• Greeks: eternal • Principles of Geology (1830) • Bible scholars: ~ 5000 years • Based on uniformitarianism • George Buffon (1707 – 1788), French naturalist • Was the geology textbook of – 75K to 2-3M years – Used observations Darwin’s day • James Hutton (1726-1797), Scottish geologist • Friend of Darwin – Founder of modern geology – Earth is incredibly old – Uniformitarianism
1 9/27/2012
Natural History and Classification Organisms and their environment
• Aristotle proposed a simple • William Paley (1743-1805) Natural Theology classification with genus and – God as Watchmaker species • Extinctions are impossible • Scala naturae: Great Chain of Being – Lewis and Clark • Karl von Linne (Carl Linnaeus, 1707-1778) • Georges Cuvier (1769-1832), French – Binomial nomenclature – Father of paleontology – Systema naturae – Extinctions are real – Was all about sex!
Change through time Change through time
• Greeks proposed it • Robert Chambers • Bible scholars forbid it – Vestiges of the Natural History of Creation (1845) – Organisms created perfectly – Organisms evolve – Immutability of species – Process is slow • Erasmus Darwin (1731 – 1802) – Emphasis on populations – Charles Darwin’s grandfather • Jean-Bapiste Lamarck (1744-1829) – Zoonomia (poem) – Zoological Philosophy (1809) – Organisms evolve in scala naturae – Inheritance of acquired characteristics – Publically ridiculed
Change through time Along came Darwin 1809—1882
• Grandfather and father were doctors • Went to Edinburgh for two semesters to study medicine – dropped out • Went to Christ’s College to be a clergyman – Studied natural theology: geology and natural history – Energetic field student – Urged to go aboard the HMS Beagle – The captain (Robert FitzRoy) needed a companion of similar social stature
2 9/27/2012
Voyage of the HMS Beagle Voyage of the Beagle
• Surveying trip – Map coastlines – Test new equipment • Naturalist on board was the doctor • Was supposed to be three year journey – went 5 • Left 1831, Darwin age 22 • Went to Azores, S. America, Galapagos, Australia, Tahiti
Voyage of the HMS Beagle Voyage of the HMS Beagle
• Darwin collected fossils and living organisms • Observations • Ship’s official naturalist left – Each Galapagos island had its own turtle, mockingbird • Darwin shipped materials back – Fossil species similar but • Became famous as a naturalist not the same as extant • Wrote several books soon after species – Similar species over land masses – Struggle for existence • Thomas Malthus
Darwin, from boat to book Alfred Russel Wallace (1823-1913)
• After the Beagle trip, married and settled in • Studied butterflies in southeast Asia the country • Knew many of the same • Studied barnacles, worms, seeds facts as Darwin • Researched like mad • Sent Darwin an outline of natural selection in 1855 • Did not work for a living • In 1858, co-authored a – Married cousin, invested, inheritance paper with Darwin on natural selection • Thought about natural selection and evolution • Not a big hit • Thousands of letters of correspondance
3 9/27/2012
Origin of Origin Natural selection sensu Darwin
• Happens when • Inspired by Wallace, finally published his draft On – More organisms are born than can survive and the Origin of Species by Means of Natural reproduce Selection, or the Preservation of Favoured Races • Competition to represent the next generation in the Struggle for Life in 1859 – Those organisms more likely to survive because of • Stressed the importance of variation within a some trait will leave more offspring species – If that trait is heritable then the offspring will have • Natural selection that trait • Common ancestry: hierarchical branching – If conditions continue then that trait will spread in – Taxonomy reflects ancestry the population
Process related to artificial selection Major Darwinian Ideas
• Natural selection • Common ancestry
Interspecific variation There are fitness consequences to this variation • Organisms vary within a species
Male tail streamers length as a predictor of reproductive success: (a) First brood breeding success, (b) Annual breeding success, (c) Successful genetic offspring in first brood, and (d) Annual genetic breeding success. Vortman Y et al. Behavioral Ecology 2011;beheco.arr139
© The Author 2011. Published by Oxford University Press on behalf of the International Society for Behavioral Ecology. All rights reserved. For permissions, please e-mail: [email protected]
4 9/27/2012
The variation is heritable Natural selection occurs
Dave Reznick
Caribbean Anoles Common Ancestry
• Phylogenetic trees
Pre-Darwinian Linnean classification Post-Darwinian Classification
Species Species Species Species Species Species Species A B E F Species D A E D Genus G Genus C Common Ancestor C Common Species Species Ancestor G B F Family H Common Ancestor H
5 9/27/2012
Phylogenetics and Taxonomy Reception of Origin
• Pre-Darwinian Taxonomy • Most scientist accepted evolution –Classification arbitrary • Natural selection not as widely accepted • Post-Darwinian Taxonomy –Classification represents lineages –Taxon = monophyletic group • Taxonomy should reflect phylogeny
Issues with Darwin To recap
• Eusocial insects • Darwin’s contributions • Mechanism of heredity unknown – Evidence that evolution happened • Time – Mechanism of evolution: natural selection – Pattern of evolution: heirarchical
Rise of the Geneticists
• Weisman's germplasm hypotheses • Early Geneticists – Contra Lamarck – Variation was discrete • Hugo DeVries – Mutations produced large changes – worked with mutations • Naturalists – genes – Most variation was continuous
6 9/27/2012
Population Genetics Population Genetics
• Resolved the dispute between naturalists and • Evolution is geneticists – Descent with modification • Modern Synthesis of 1940’s – Change in gene frequency – Ronald Fisher – Theodosius Dobzhansky – Sewall Wright – JBS Haldane – Ernst Mayr – George Simpson
7