Chapter 24 - Chapter 24: Evolution by Natural Selection...

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Unformatted text preview: Chapter 24: Evolution by Natural Selection Evolution of Evolutionar y thought Aristotle Lamarck Darwin and Wallace Evidence Extinction changes the species present over time Similar Typological thinking is based on the idea that species are unchanging types and that variations within species are unimportant or even misleading. Used by Plato and other Greek philosophers and said God/perfect essence made unchanging organisms Great chain of being, scale of nature, a ladder that increased in size or complexity. Species are fixed types and some species are higher, meaning some are better than others. Species are not static, but change through time. Simple species start at the base of the chain by spontaneous generation then evolve by moving up through the chain over time. Species change through time via inheritance of acquired characters. Evolution occurs because traits vary among the individuals in a population, and because the individuals with certain traits leave more offspring than others do. Population- individuals of the same species that are living in the same area at the same time Population thinking- variation among individuals in a population was the key to understanding the nature of species Revolutionary because: (1) overturned the idea that species were static and unchanging (2) replaced typological thinking with population thinking (3) was scientific made predictions that could be tested through observation and experimentation Descent with modification- the phrase used by Darwin to describe his hypothesis of evolution by natural selection Species change through time and are related by common ancestry Fossil- any trace of an organism that lived in the past. Bones, branches, shells, tracks Fossil record- consists of all the fossils that have been found and described in the scientific literature Extant species- the species living today Geologic time scale- a sequence of named intervals called eons, eras, and periods that represented the major movements in Earth history. Indicated that the earth is much older than the 6000 years claimed by the theory of special creation, instead it’s about 4.6 billion than the 6000 years claimed by the theory of special creation, instead it’s about 4....
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This note was uploaded on 03/21/2012 for the course BIOSC 160 taught by Professor Coffman during the Spring '10 term at Pittsburgh.

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Chapter 24 - Chapter 24: Evolution by Natural Selection...

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