Transcript Lecture 1
Paul Gauguin, 1897 Where Do We Come From, What Are We, Where Are We Going “Nothing in biology makes sense except in the light of evolution.” Theodosius Dobzhansky Theories of Evolution • Origin Myths/Cosmologies – Greek – Prometheus – Genesis Western examples Left: Prometheus and Athena Top: God and Adam Creation as Calculated from The Bible Bishop James Ussher (as painted between1640-1656) Bishop John Lightfoot (b. 1601- d. 1675) Ancient Greek philosopher Anaxiamander (611547 B.C.) and the Roman philosopher Lucretius (99-55 B.C.) conceived of the idea that all living things were related and that they had changed over time. Lucretius Aristotle’s Great Chain of Being (Scala Naturae) Early Ideas about Evolution Comte de Buffon (Georges Louis Leclerc) 1707-1788 Jean-Baptiste Lamarck 1744-1829 Erasmus Darwin 1731-1802 Baron Cuvier 1769-1832 Other Theories • Creationism accounts for biological diversity by referring to the divine act of Creation as described in Genesis. • Catastrophism is a modified version of Creationism, which accounts for the fossil record by positing divinely authored worldwide disasters that wiped out the creatures represented in the fossil record, who were then supplanted by newer, created species. • Intelligent Design states that modern physics and cosmology have uncovered evidence for intelligence in the structure of the universe and this intelligence seems to act with us in mind and that the universe as a whole shows evidence of design. Jean Baptiste Lamarck, 1744-1829 • French geologist and naturalist • published Philosophie Zoologique in 1809 • speculated about mechanisms of biological evolution, offered no evidence • Lyell discussed Lamarck’s ideas in his Principles of Geology Ideas of Lamarck that were rejected by Darwin • evolution is a process in which living things gradually become more perfect (more human-like) • because species that evolve and improve leave a gap, new species must be continually created by spontaneous creation • the inheritance of acquired characteristics is the mechanism of evolution (but inheritance of acquired characteristics was not entirely rejected by Darwin) Charles Darwin: failed medical student, failed divinity student, ardent beetle collector, naturalist on HMS Beagle Voyage of H.M.S. Beagle, 1831 - 1836 90 feet of ship, 74 people living together for 5 years... Darwin’s voyage on HMS Beagle took five years and went east to west, staying largely within the SE trade winds in the southern hemisphere. This is a favorite route for cruisers today, but not racers, who prefer to go west to east and stay in the roaring forties around Antartica. Understanding the Depth of Time James Hutton Charles Lyell 1726-1797 1797 - 1875 Understanding Populations Populations Thomas Malthus Thomas Malthus 1766-1834 1766-1834 Darwin and Alfred Russel Wallace (1823-1913) • Darwin developed ideas on natural selection in early 1840s (1844 essay), but did not publish • He received a letter from Wallace in 1858 outlining natural selection • His friends organized an 1858 presentation in London of Wallace’s and Darwin’s work • 1859 publication of Origin of Species Darwin and Wallace Volumes Darwin’s Theories of Evolution Natural Selection • • • • Individuals within species vary Some variations are passed to offspring More offspring are produced than can survive (Malthus’ influence) Survival and reproduction is not random. Individuals that have favorable variations more often survive to reproduce, or reproduce more. The Darwinian view of life has two main features • the diverse forms of life have arisen by descent with modification from ancestral species • the primary mechanism of modification has been natural selection working over enormous tracts of time The Beagle in Sydney Harbor Darwin’s Theories of Evolution Common descent every group of organisms descended from a common ancestor Carl Sagan’s Universe Calendar • 24 days = 1 billion years • 1 second = 475 years • • • • • “Big Bang” Milky Way Solar System Life on Earth Humanlike Primates January 1 May 1 September 9 September 25 Milky Way December 31, 10:30pm