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Unformatted text preview: Origin Of Life-Prebiotic evolution- evolution of complex networks of organic compounds before the origin of life-spontaneous generation-Miller/Urey experiment- Modeled Earths primordial atmosphere in the lab. They Mixed water, carbon dioxide, nitrogen, methane, ammonia, and hydrogen (primordial reducing atmosphere), then Passed electric sparks through the mixture. Amino acids spontaneously formed in the mixture. There are many possible sources of energy for prebiotic evolution: UV - ultraviolet radiation - no protective ozone layer around early Earth, Lightning - probably more frequent, powerful storms as the Earth gradually cooled, Heat - molten mantle etc., Radiation - radioactive decay of elements.-Panspermia- theory that life was seeded on earth in a passive/active way Evolution Before Darwin-Chain of Being- Species could be arranged in a linear sequence, like links in a chain. The Chain of Being dates back to Aristotle. Also known as the scala natura , the ladder of nature. -Argument from design- Naturalists before Darwin viewed evolution as the unfolding of a predetermined supernatural plan.-John Ray- wrote Wisdom of God in Creation (1691), created Natural Theology, which said that the wisdom of god could be understood by studying his creation (the natural world). -William Paley- revived Natural Theology, Paleys Natural Theology (1802), greatly influenced Charles Darwin. Paley believed god created everything, species were fixed and arranged in a linear sequence (chain of Being). -Carolus Linnaeus- Swedish botanist tried to reveal the divine plan through classification of plants.-System of Hybridization- new species must be hybrids of existing species - ignored adaptation of species to changing conditions Georges Comte de Buffon- wrote Histoire Naturelle , Buffon theorized that animals diverged from a common ancestor. Buffons theory had two very modern ideas: 1. Biogeography (geographical distribution) was important in understanding natural history. 2. Environment can influence the basic nature of animals-Jeane Baptiste de Lamarck- believed that organisms were shaped by the environment and could evolve. He was Buffons protg. Best known for his theory of the Inheritance of Acquired Characteristics- Changes in the living body could be passed on to descendants (ex. giraffes necks). Lamarck thought that evolution had to be both predetermined and progressive. He was a materialist - revived the idea of spontaneous generation. Thought that the Chain of Being was an oversimplification, nature followed a branching scheme (= modern). Once generated, organisms changed along fixed and parallel paths - Theory of Organic Progression.-Robert Chambers- the last great champion of the 19th Century fascination with progressivism. Chambers System of Linear Development was a very Lamarckian theory. Chambers Vestiges of the Natural History of Creation (1844) caused a scandal, it Claimed that man was descended from the lower animals ( = modern),...
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This note was uploaded on 03/27/2008 for the course EBIO 101 taught by Professor Fleury during the Spring '08 term at Tulane.
- Spring '08
- An Essay on the Principle of Population