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Lecture 24

SCILIVSY 12 Lecture Notes - Lecture 24: Carl Linnaeus

General Education
Course Code
Professor Berry

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SLS 12 Section 12 Name: Alex Simon
The Origin of Species
Study Guide
Chapter 13: Mutual Affinities of Organic Beings….
In this chapter, Darwin discussion the classification of organisms -- the “Natural
System” introduced by Linnaeus. While most of the adherents to this system
believed it reflected the plan of the creator, Darwin believed it flowed from his
theory. Why?
Darwin acknowledges the that while naturalists have developed ways of grouping
certain organisms together through common appearance or structure, they did
not explain the reasoning behind why these organisms should be grouped
together. Darwin discusses the “Natural System” and uses it in order to defend
his theory of descent with modification – claiming that species are able to be
grouped by genera and families due to the fact that species descended from one
another and the “Natural System” simply illustrates this path. Darwin further
defends his theory by arguing against the belief that all species were created
individually, due to the imperfection of species. Darwin mentions that if species
were created in order to be perfectly fit for their specific environment, we would
not find organisms with rudimentary organs. Darwin ultimately determines that
the theory of natural selection perfectly explains the presence of rudimentary
organs, since natural selection simply rids an organism of disadvantageous
characteristics when naturally selecting for advantageous variations and leaves
innocuous traits alone.
Chapter 14: Recapitulation and Conclusions
What line of evidence recapitulated in this chapter was the strongest support for
descent for modification in Darwin’s opinion? Explain.
Darwin believes that all living beings belong to a chain of descent, which connect
all of them to a single original form. Darwin claims that once scientists accept this
descent from a common being, the categorization between species and varieties
will no longer hold value. Once this common thread is understood, there will be
no reason to categorize species without explanation, since they will easily be
able to trace chains of descent. In defense of his theory of descent with
modification, Darwin discusses the existence of variations in nature, species
engaging in a struggle for existence, competition, and natural selection.
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