3.3 Evolution and Eugenics

theory of natural selection

explanatory theory of the evolution of organisms developed by Charles Darwin

5 basic principles of theory of natural selection

variation

over reproduction

competition

advantage

modification by descent

artificial selection 

process of humans, modifying animals from generation to generation through selective breeding 

comparative psychology 

field of psychology that compares cognition, memory, and learning across different species of animals 

eugenics 

movement in early part of 1900s that was motivated to improve human race 

eugenicists misappropriated theory of evolution and intelligence testing for their discriminatory agenda 

characteristic of highly intelligent animals is 

expansion of the cerebral cortex 

social brain hypothesis

theory to explain the rapid evolution of human brain based on pressures for expanding the social lives of our ancestors

expensive tissue hypothesis

theory to explain evolution of human brain baed on idea that we evolved to have a diet and digestive system that required less energy, which allowed our energy-expensive brain to develop

Darwin developed the theory of natural selection to explain 

the evolution of organisms during his five-year voyage on the HMS Beagle 

the five postulates of the theory of natural selection are

variation of traits within a population

a tendency for over-reproduction, but populations remain stable

competition for survival and reproduction

some members of a population have genetic advantages and so survive and reproduce better than others

organisms change over generations as natural pressures change- modification by descent

darwin was interested in

physical, behavioral, and psychological evidence that would support his theory

the research and theories of early psychologists, like Romanes, Pavlov, Thorndike, and Freud, were 

highly influenced by the theory of natural selection 

darwin’s theory of natural selection influenced Romanes to look for commonalities in animal intelligence,

which led to the development of the field of comparative psychology

eugenics was a movement in the late 1800s and early 1900s that applied the theory of natural selection to humans by

promoting the reproduction of people with “good” genes and discouraging or preventing the reproduction of people with “bad” genes 

the eugenics movement misunderstood and misapplied darwin’s theory of natural selection, which led to

extreme discrimination, sterilization of thousands of women in the United States, and genocide in Nazi Germany

the human cerebral cortex has gone through an incredible increase in size and complexity during our short evolution. The social brain hypothesis suggests

that human brain evolution was fostered by our increasingly complicated social lives and the need for complex forms of communication.

The expensive tissue hypothesis suggests the human brain requires a great deal of energy, so for it to evolve, we also had to evolve a relatively simple digestive system

the human brain requires a great deal of energy, so for it to evolve, we also had to evolve a relatively simple digestive system