[[@flancian/history of evolutionary thought]]

📕 subnode [[@flancian/history of evolutionary thought]] in 📚 node [[history-of-evolutionary-thought]]

📄 pushed from garden/flancian/capra course.md by @flancian

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[[history of evolutionary thought]]
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  [[charles darwin]]
  - based his theory on two core ideas:
    
    [[chance variation]] -> [[random mutation]]
    
    [[natural selection]]
  - all living organisms are related by common ancestry
  - [[beagle]]
  - Darwin knew not of a remedy to a problem of his theory: he thought heredity worked so that offspring received 50% of the traits of each ancestor, their offspring 25%, theirs 12.5%, etc.
    
    Darwin saw this as a flaw as it showed that positive traits would disappear very quickly after arising and being selected by chance.
    
    [[Mendel]] of course discovered the units of heredity, [[genes]].
    
    [[Mendel]] wrote to [[Darwin]] ()!), and allegedly Darwin didn't read the letter because it was in German and had too much math on it (!).
- [[radical shift]] in biological thought: from [[being]] to [[becoming]] (a shift towards change)
- [[holistic view]]
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  [[neodarwinism]]
  - evolutionary variations result from random mutations, being random genetic changes, followed by natural selection.
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  [[systems view of evolution]]
  - recognizes three major avenues of evolution:
    
    [[random mutations]] == [[genetic mutations]]
    
    most mutations are harmful, few lead to positive variations
    
    note that one bacteria can become [[billions]] in just one day
    
    [[horizontal genetic transfer]] == [[gene trading]]
    
    [[bacteria]] freely trade genes, swap genes with each other
    
    global trading of genes (!)
    
    [[lynn margulis]]
    
    some [[microbiologists]] argue that [[bacteria]] should not be categorized into [[species]]
    
    during the first [[2 billion]] years of evolution, only bacteria were around
    
    [[bacteria]] bootstrapped it all, established the global system
    
    #push [[bacteria]] also invented:
    
    [[fermentation]]
    
    [[photosynthesis]]
    
    [[nitrogen fixation]]
    
    [[rapid motion]]
    
    [[respiration]] (!)
    
    [[symbiogenesis]]
    
    [[evolution through symbiosis]]
    
    [[lynn margulis]] as well
    
    hypothesis: long term [[symbiosis]] involving [[bacteria]] and other [[microorganisms]] as hosts/guests led to complex life
    
    [[acquiring genomes]]
    
    compares organisms to [[corporations]]
  - all three of the previous produce changes that need to be integrated into the physical and chemical environment; if the integration of new genetic information doesn't work, the organism can't survive -> there's natural selection
  - [[epigenetic network]]
  - real life example: in human life you make plans (you have a plan for your night), plans need to adapt to random occurrences (people you run into; other events out of your sphere of control). evolution works the same way.
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  [[david brower]] narrative: compresses 4.5B years (the [[age of the earth]]) into the six days of [[biblical creation]]
  - [[sunday midnight]] creation
  - [[tuesday 8am]] first bacterial cells
  - [[thursday midnight]] planetary system
  - [[friday 4pm]] sexual reproduction invented
  - [[saturday]] all visible forms of life evolved
    
    [[1.30am]] first marine animals
    
    [[9.30am]] first plants come ashore
    
    [[16.50]] great reptiles, roam for five hours
    
    [[17.30]] first mammals
    
    [[22]] first primates
    
    [[23]] first monkeys
    
    [[23:40]] great apes appear
    
    [[23:56]] [[homo habilis]]
    
    [[23:59:30]] [[homo sapiens]] begins to evolve
    
    [[23:59:49]] humans
    
    less than one second before midnight: [[written history]]
- [[australopithecus afarensis]]
  - [[big brains]] seem to have yielded all these innovations [[four million years ago]]:
    - [[language]]
    - [[reflective consciousness]]
    - [[tool making]]
    - [[social]]
- [[homo habilis]] [[two million years ago]]
- [[homo erectus]]
- [[homo sapiens]] [[250k years ago]]
  - [[cro magnon]] -- anatomically identical to us. fully developed [[language]]. brought about an explosion of technological and artistic innovations.
    - [[lascaux cave]]
    - [[chauvet cave]]
      
      [[300 paintings]] of high artistic achievement and with a [[narrative]]

📖 stoas

public document at doc.anagora.org/history-of-evolutionary-thought
video call at meet.jit.si/history-of-evolutionary-thought

⥱ context

To see links, go up to full node [[history-of-evolutionary-thought]].