ANTHRO 1 Lecture Notes - Genetic Drift, Deep Time, Hemoglobin
Lecture 2: the logic of natural selection
● Design logic
○ Designed by external intention
○ Parts precede whole
○ Assembled to achieve a function
○ Ex: lawn chair man
● Organic logic
○ Self-organized by interaction
○ Parts differentiate out of a prior integrated whole system
○ Ex: human development in womb
● Evolution: fact
○ Evidence of fossil species/sequences that parallel each other in different parts of
the globe
○ Rapidly-occurring evolution: rat speciation, human disease, antibiotic-resistant
bacteria, etc
○ Genome investigation → rich source of proof for molecular
change/lineage/relationships between species
○ Deep time scale: fossils of bacteria from billions of years ago
○ Molecular continuity + functional continuity
○ Increasing complexity
○ Rich + complex fossil record
● Evolution: theory
○ Natural selection (NS): darwin and wallace in 1859
○ Still in development, subject to modification
○ NS is not the only relevant process in biological evolution
■ Cosmic catastrophe
■ Statistical “drift”
■ Gene loss
○ Other factors: mass extinctions
■ Unrelated to adaptation
■ Contribute to random “drift”, as do population size and molecular
accidents
● Biological isn’t just a physical science
○ Function, design, purpose are irrelevant in geology and meteorology
○ Hemoglobin: production, structure, location can’t be understood without
functional questions
○ Biology struggles with “design” questions
● Aristotle’s theory of causality: “that for the sake of which something occurs”
○ Material cause: solidity of brick, strength of wood
■ Intrinsic nature, continuity of properties
○ Efficient cause: cutting, moving, attaching parts
■ Mechanically-forced change, work
○ Formal cause: forms required to achieve result
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Document Summary
Parts differentiate out of a prior integrated whole system. Evidence of fossil species/sequences that parallel each other in different parts of the globe. Rapidly-occurring evolution: rat speciation, human disease, antibiotic-resistant bacteria, etc. Genome investigation rich source of proof for molecular change/lineage/relationships between species. Deep time scale: fossils of bacteria from billions of years ago. Natural selection (ns): darwin and wallace in 1859. Ns is not the only relevant process in biological evolution. Contribute to random drift , as do population size and molecular accidents. Function, design, purpose are irrelevant in geology and meteorology. Hemoglobin: production, structure, location can"t be understood without functional questions. Aristotle"s theory of causality: that for the sake of which something occurs . Material cause: solidity of brick, strength of wood. Formal cause: forms required to achieve result. Final cause: the goal, ex to protect from weather. Ns inverts logic of physical causality (x happens, y follows) Darwin showed how appearance of purposive design can precede results.
