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The Dragons Of Eden Chapter Summary

Decent Essays

In the novel the Dragons of Eden the concept of evolution of the human brain is introduced. The book starts off with a "cosmic calendar" that is the representation of everything that happened in history within the span of a year. The first 11 months are considered to be the time period from the big bang to when life first became possible on Earth. In continuation December takes the events from first life to the start of human life. Sagan then expresses all of human history to take place on December 31st. The book later goes on to describe the basis of life forms including DNA and its function. Furthermore, Sagan goes into depth of the evolution of the brain. The book ties in with the concepts of evolution (Big Idea 1) and the way information is stored in organisms (Big Idea 3). …show more content…

The cosmic calendar is used to show how life went from single cell eukaryotes all the way to the complex organisms that we have today. Today we understand that changes in genes naturally and the gene pool that is successful will survive and those genes will be passed on. Sagan notes how fish have a central nervous system and a very small brain to control only vital systems such as maintain heartbeat, or breathing patterns. However, in animals such as dolphins the cerebral cortex is enlarged and this leads to a sense of higher thinking,. Humans also have an unnaturally large cerebral cortex which allows for the ability to think above what is necessary for survival. The cerebral cortex is "important in more complex cortical functions including memory, language, abstraction, creativity, judgment, emotion and attention" (Dartmouth). This region of the brain is larger in these beings due to evolution and the ability for the animals to sustain a larger

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