9/6/20171Evolution & Darwin’s TheoriesDARWIN, CHARLES ROBERT (1809-1882) 29/6/201723History of Evolutionary Thought before Darwin“You have to know the past to understand the present.”Dr. Carl SaganThree Paths Leading to the Recognition of Human Evolution1) Explaining the Variation in Life Forms2) Recognizing the Antiquity of the Planet3) Recognizing the Antiquity of Humanity49/6/20173Aristotle (384-322 BC) “Father of Natural Science”51) Explaining the Variation in Life Forms• Scala Naturae: Great Chain of Being• Entrenched in the notion of Platonic “idealism” or “theory of Forms”Adoption by the Christian church61) Explaining the Variation in Life Forms• Each species is a perfect creation and unchanging = essentialism• God created humans above all animals– Angels above humans9/6/201747Archbishop James Ussher (1581-1656)• Genesis – “Begats”– Adam begat Seth, Adam lived for 930 years . . .• Earth was created on Saturday, October 22, 4004 BC, 6:00 PM72) Recognizing the Antiquity of the Planet8By the end of the Renaissance, this left us with two obstacles to developing a scientific theory of evolution• Young Age of the Earth• Fixity of Species89/6/201759Georges Louis Leclerc, Comte de Buffon (1707-1788)• Cooling experiments• Earth could be 3-4 million years old but certainly 75,000• Greatly pushed back the origin of the earth• Empirical studies• “Degeneration” of life forms due to bad environments* point of creation* **time 92) Recognizing the Antiquity of the Planet10Charles Lyell (1797-1875)• Leading proponent of “Uniformitarianism” (coined by James Hutton)• Gradualism of Geological processes– Acquaintance of Darwin’s– Contributed to disproving the “young Earth” hypothesis through the geology of Mt. EtnaCopyright 2009 Pearson Education Inc.2) Recognizing the Antiquity of the Planet9/6/20176Lord Kelvin, William Thompson (1824-1907)112) Recognizing the Antiquity of the Planet• Cooling body experiments• Earth must be 100 million years old (we now know it to be ~4.5 billion years old)12Carolus Linnaeus (1707-1778)• Systema Naturae: a hierarchical classification of life• Taxonomy– Linnaean hierarchy• Binomial nomenclature of genus & species• Homo sapiensCopyright 2009 Pearson Education Inc.1) Explaining the Variation in Life Forms9/6/2017713Carolus Linnaeus (1707-1778)• Systema Naturae: a hierarchical classification of life• Unified classification system– Rosa sylvestris inodora seu canina– Rosa sylvestris alba cum rubore, folio glabro– gorilla• Binomial system still used• First to group humans with apes– Humans are animals• Not (quite) an evolutionist• Systema Naturae: a hierarchical classification of life• Taxonomy– Linnaean hierarchy =• Binomial nomenclature of genus & species• Homo sapiens• Why was Linnaeus’ contribution important to modern day evolutionary theory?Wikipedia Creative Commons license1) Explaining the Variation in Life FormsMnemonic: Did King Phillip Cry Out, “For Goodness’ Sake!”?14Georges Cuvier (1769-1832)• Comparative Functional Anatomy: demonstrating a carnivore (i.e., a lion) from its tooth.• Needed to address the increasing number of fossils of organisms that exist nowhere on the earth today.Bryce Canynon, Utah, © Stephen Marshak1) Explaining the Variation in Life Forms• “Extinction” & “Catastrophism”, eventually defeated by Lyell9/6/2017815Jean-Baptiste Lamarck (1744-1829)• First comprehensive, scientific theory of evolution• Mechanism: Inheritance of acquired characteristics• 1) Change in environment causes changes in behavior– Relationship between environment & organism – a new idea• 2) Changes developed within the lifetime of an individual are heritable• Challenged the belief that species were immutable151) Explaining the Variation in Life Forms16Thomas Malthus (1766-1834)• Populations have the capacity to increase exponentially• This leads to overpopulation, war, famine, disease, etc.• Natural populations are kept in check by forces which kill off members of that population1) Explaining the Variation in Life Forms9/6/20179Questions17Charles Darwin (1809-1882) 18© AKG/ Photo Researchers, Inc.1) Explaining the Variation in Life Forms• Took a long time to find his niche: minister, doctor, etc.• 1831 HMS Beagle sets sail with Darwin as naturalist; Darwin brings books written by Lyell, Malthus, among others• 1836 Beagle returns from trip around the world• 1837 Darwin begins his first notebook on the “transmutation” of species• 1855 Wallace writes a paper equivalent to Darwin’s argument • 1858 Darwin & Wallace give a joint paper on species origins to the Linnaean Society9/6/2017101859: “On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life”Although both Darwin and Wallace independently theorized evolution by Natural Selection, Darwin is the one who continued in this line of research19Jacques Boucher de Perthes (1788-1868)• Father of Paleolithic Archaeology• Excavations in the Somme Valley, France• Proved association of human-made artifacts with extinct fauna (animals) c.1847-1858.• The Industrial Age made the paleontological & archaeological record hard to ignore!203) Recognizing the Antiquity of Humanity9/6/2017111859: the Pivotal Year• Darwin publishes On the Origin of Species.• British geologists John Prestwich & Charles Lyell and the archaeologist John Evans visit the excavations of Boucher de Perthes and accept his claims for their antiquity.• Thomas Huxley correctly identifies the fossil specimen discovered in 1856 in the NeanderValley, Germany, as an extinct species of human; we now call this fossil a Neanderthal.21Artificial Selection• Darwin’s genius was in seeing that nature—the environment, food sources, predators—does the same thing in the present!• He called it “Natural Selection”• The MAIN difference between the two is that Natural Selection does not have a long-term goal, unlike Artificial Selection.• Because of the uniformitarian extension of present processes during the long antiquity of life of Earth, this led to his 5 Theories.22For more than 10,000 years we’ve selected traits that we find desirable & purposefully influencing the breeding of domesticated animals9/6/201712Darwin’s 5 theories regarding evolution1. Species change [evolution as
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