History of Evolutionary Thoughts - Lecture Notes | ANP 340, Study notes of Physical anthropology

Download History of Evolutionary Thoughts - Lecture Notes | ANP 340 and more Study notes Physical anthropology in PDF only on Docsity!  History of Evolutionary Thought o ANP 340  Darwin and Natural Selection  Western Ideas About the World and Biological Diversity ca. 1600 - 1860 o Creationism: accounts for biological diversity by referring to the divine act of creation as described in Genesis. o Four related ideas  Separate creation  A young earth: Archbishop Ussher says the earth is 6,000 years old  An unchanging earth and permanence of living things  Catastrophism: any changes are due to catastrophic events  Before Darwin – Observations Made o Fossils: could observe change through time o Remnant organs: body parts not functioning or needed o Vertebrate anatomy: template or common ancestor? o Embryo development: common ancestor o Plant and animal breeding: variation o Struggle for existence in animal world o New exploration: great diversity  Aristotle o 384-322 BC o Scala Naturae, or “Great Chain of Being.” o Living things are….  Ranked  Unchanging  Humans are at the top  Great Chain of Being  Carolus Linneaus o 1707-1778 o Swedish botanist o Father of Taxonomy  Standardized classification system o Systema Naturae (1735)  Hierarchical, nested classification system based on phenotypic observations  Binomial nomenclature : two word naming system for naming species (Genus then Species)  Species are fixed, unchanging  Notably placed humans within the same classificatory scheme as the rest of species.  (Very) Basic Linnean Taxonomy o Kingdom o Phylum o Class o Order o Family o Genus o Species  Linneaus and Humans  Buffon o French Naturalist o 1707-1788 o Considered the possibility of “improvement” and “degeneration” in life forms o Earth may be up to 75,000 years old (revolutionary!) o Humans were one species  Jean-Baptiste de Lamarck (1744-1829) o 1744-1829 o Philosophie zoologique (1809)  Species are not fixed  Inheritance of acquired characteristics  Change in environment changes the needs of organisms  their behavior changes  leads to more or less use of a structure (arm, neck, etc.)  leads to greater or lesser size, can shrink or disappear.  All these changes can be inherited o Also believed in a “scala naturae” where species gradually became more perfect  Lamarckian Evolution  Georges Cuvier o 1769-1832 o “Father of Paleontology” o Rejected early evolutionary ideas o Species did not change, but… o Recognized extinction in fossil record o Strong proponent of catastophism o Wallace Effect - Natural selection can lead to speciation by facilitating reproductive isolation o Staunchly refused to use evolutionary theory to discredit the intelligence and creativity of non-Europeans  On the Origin…why so successful? o Darwin was incredibly influential o His mechanisms were clear o Backed up statements with numerous examples (from his time on the Beagle) o And, the time was right…  Darwin’s Theory of Evolution  All species are capable of producing offspring faster than the food supply increases.  All living things show variation; no two individuals of a species are exactly alike.  Because there are more individuals than can possibly survive, there is a fierce struggle for existence and those with a favorable variation in size, strength, running ability, or whatever characteristics are necessary for survival, will possess an advantage over others.  These favorable variations are inherited and passed on to the next generation.  Over long time periods, these successful variations produce great differences that result in new species.  Darwin’s Tree of Life o Darwin was willing to entertain the idea of biological change – new species could evolve from ancestral forms  Darwin and Humans o Descent of Man (1871)  Humans seem so different from apes because transitional forms have become extinct  Humans are one species but perhaps different subspecies  Seemingly non-adaptive traits are preserved within a species due to sexual selection/reproductive advantage (Next section will tie in a bit with first Lab; on the 19th now)  Darwin’s contributions included an eloquent argument for evolution in general AND the role of natural selection BUT No one in the 19th C. understood the source of the variation upon which natural selection worked o “Our ignorance of the laws of variation is profound. Not in one case out of a hundred can we pretend to assign any reason why this or that part differs, more or less, from the same part in the parents.” (Darwin 1859)  Darwin and Pangenesis o Pangenesis- Dawin’s explanation of heredity (1868) o Gemmules- particles shed by cells that circulate through the body and, via germ cells, transmit traits from parent to offspring o Variation arises because gemmules change qualitatively over the life course o Galton inadvertently disproved pangenesis