ANTH 204

Textbook: How humans evolved Boyd R & Silk J. B (2023). 10th edition

What is anthropology?

• The study of humans, our closest relatives, and our ancestors

• Diff between psych and anth is that anth focuses on relatives and ancesors, rather than just humans
  
  

Anthropology umbrella

• Archaeology
  
  

• Cultural anthropology

  • Cultural perspective

  • Understanding language
    
    

• Biological anthropology

  • This class focuses on this

    • Primatology

    • Molecular Anthropology

      • Human genetics

    • Paleoanthropology

      • Fossil records of humans

      • Starts with earliest primates

    • Forensics Anthropology

    • Human Biology

      • Bioarchaeology
        
        

• Linguistic anthropology

• All of these subsections combined makes up Applied Anthropology
  
  

Lec 3

Adaption by Natural Selection

• Natural Selection

  • Allows an indiviudal to maximize fitness

    • survival

    • reproduction

    • These could be structural, physiological, behavioral
      
      

  • Process that produces adaptation

  • Heritable traits that are favorable increase in freq in successive generations

• Natural Selection Terms

  • Evolution-biological change over time via descent with modification

  • Trait-inherited feature acted upon by NS (adaptation)

  • Species group means animals that breed with each other
    
    

• Charles Darwin

  • First planned to enter the clergy

  • Educated at Cambrdige

  • 5 year voyage on H.M.S Beagle

  • Galapagos Islands

  • First to look into natural selection

    • He looked into Galapagos Finches

    • Many species

    • Occupied differnet niches

    • different beak shapes, otherwise similar

    • On the island of Galapagos these birds are all different but they all share a common ancestor
      
      

• Darwin’s Theory of Adaptation

  • Species have changed over time

  • Evolution now a new idea

  • Darwin’s contribution was mechanism

    • Natural selection
      
      

• Darwin’s Postulates

  • There is a competition for existence

  • There is varaiton in features related to survival and reproduction

  • This variation is heritable (passed from generation to generation)
    
    

• Differential selection

  • Survival and reproduction of the fittest

  • Fitness

    • But not like speed or strength but more like an animal’s ability to reproduce and make sure your off-spring survives
      
      

• Galapagos Islands, Ecuador

  • Darwin’s finches

  • Medium ground finch

  • Peter and Rosemart Grand, Princeton

  • This entire study was documented in The Beak of the Finch
    
    

• Postulate 1: Competition

  • 1976 - 1978

  • 1400 birds reduced to 180

  • A drought occured during their experiment and so as the seeds went down because its dry, the bird’s numbers went down too
    
    

• Variation

  • Morphology

    • An organism’s size, shape, and composition

    • The bird’s beak’s depths started changing in correlation to the drought

    • When the drought happened, the seeds get harder and so this makes it that the birds who survived, they have deeper beaks
      
      

• Heritability

  • Beak depth passed from parent to offspring

  • Parents had deeper beaks which made it so that their kids also had deep beaks
    
    

• Histograms provide us the average when looking at the middle of the graph

• The smaller the bars the less the population, but where the bars lie is where the actual measurements/depth come in
  
  

• Individual selection

  • Selection operates on level of individual

  • Example: blue monkey

    • High vs low fecundity (ovulate frequently, want sex often) females

    • High fecundity favored even at species expense (overpopulation)
      
      

• Natural Selection operates at the level of the individual (not the species)
  
  

• Stabilizing Selection

  • Average phenotype is favored while extreme variations are selected against

  • If you’re too good or too bad you get left behind

  • Upside down U curve
    
    

• Directional Selection

  • Larger favored individuals are in favor when peak shifts in one direction

  • If the U curve goes to the left, then the people already on the extreme left will be safe since now they’re average

  • If the U curve goes to the right, then the people already on the extreme right will be safe since now they’re average

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• Types of variation

  • Continuous

    • variation in traits (weight, beak size, skin/hair color) that are distributed on a continuum
      
      

  • Discontinuous

    • variation in which types can be grouped into discrete categories with no intermediates