Darwin1 - The Lead-up to On the Origin of Species...

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1 The Lead-up to On the Origin of Species Epigenesis vs. Preformationism Close historical and conceptual relation between formation of species and development of individual organisms: – Both involve the creation of organized systems from something less organized Two competing perspectives on development: – Epigenesis: mechanical causal processes combined to create near organisms Challenge—inconceivability of making complex forms in this way – Preformationism: All organisms preformed in the initial creation Development consisted of the growth of the seed into the organism Theorists differed over where the seed existed— female egg, male sperm, in the soil Species and classification History of classification systems, usually focused on practical objectives (plants as medicines) The 17 th and 18 th centuries were a period of exploration, with explorers bringing back to Europe many specimens of life found elsewhere – Need to organize these The Swede Karl von Linné (Linnaeus: 1707-1778) was himself an explorer and sought to develop a natural system of classification
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2 Linnaeus ` task How to define what a species is ( i.e. a theoretical l species concept z ) How to show the relationships between species How to develop a method of classifying any given specimen Essentialism—each species has an essence, set down in the type specimen Species are separately created Each species has a place in the economy of nature Linnaeus’s System Extended the species-genera relationship to higher levels: genus, order, family, kingdom Tried to create a rational basis for identifying similarities – in plants, used sex organs (number & arrangements of pistils, stamens) as the major basis for grouping – Not always perfect: grouped conifers such as pines, firs, and cypresses as well as a few true flowering plants, such as the castor bean, in the Class Monoecia (separate male and female "flowers" on the same plant), Order Monadelphia (multiple male organs joined onto one common base) grouped algae, lichens, fungi, mosses and other bryophytes, and ferns together as plants that lacked obvious sex organs in the Class Cryptogamia, or "plants with a hidden marriage." Classifying humans Anthropomorpha: Races as varieties or sub-species Species could undergo trans formation s (but not trans mutations ) by: – Hybridization – Selection (these could act separately or together) Could generate varieties , l races z or subspecies, but not new species (essences)
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3 William Paley (1743-1805) l In order to pass the B.A. examination, it was, also, necessary to get up Paley's Evidences of Christianity , and his Moral Philosophy . . . The logic of this book and as I may add of his Natural Theology gave me as much delight as did Euclid. The careful study of these works, without attempting to learn any part by rote, was the only part of the Academical Course which, as I then felt and as I still believe, was of the least use to me in the education of my mind. I did not at that time trouble myself about Paley's
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This note was uploaded on 12/12/2011 for the course PHIL 147 taught by Professor Bechtel,w during the Fall '08 term at UCSD.

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Darwin1 - The Lead-up to On the Origin of Species...

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