Essentials of Physical Anthropology, 7th Edition
CHAPTER 2: THE DEVELOPMENT OF EVOLUTIONARY THEORY
After reading Chapter 2, you should be able to…
1. Trace the development of theories of biological evolution in light of advances in the natural sciences, resulting in part from the age of discovery & exploration 2. Understand Western European world views (e.g., the notions of fixity of species & a general sense of stasis) & how these notions inhibited the development of theories of biological evolution 3. Discuss the contributions of 18th & 19th century scientists to evolutionary theory 4. Understand the theory of evolution by means of natural selection, developed independently by Charles Darwin & Alfred Russel Wallace 5. Understand the importance of variation in species & how natural selection acts on this variation through differential reproductive success to alter species 6. Discuss the shortcomings of Darwin’s explanation of evolution in reference to 19th century genetics & theories of inheritance 7. Discuss the present level of acceptance of evolutionary theory in the U.S.
A. Misconceptions about evolution result from the poor quality of education (particularly science education & especially biology) in the U.S. B. In the United States, evolution is considered to be anti-biblical & is often denigrated as being “only” a theory. 1. Evolution is, in fact, a scientific theory that has a wealth of support & is the unifying theory of the biological sciences, including physical anthropology. 2. There is ample proof that humans & apes last shared a common ancestor 5 to 8 m.y.a.
II. A Brief History of Evolutionary Thought
C. Discoveries of evolutionary principles took place in Western Europe through many ideas borrowed from other non-western cultures. D. Charles Darwin is credited with formulating the theory of natural selection, although Alfred Russel Wallace independently duplicated Darwin’s ideas. E. The predominant European worldview throughout the Middle Ages was one of stasis & the fixity of the species. 3. Christian teachings that God created all life were taken literally. 4. Additionally, most believed that life could be ranked in a hierarchy called the Great Chain of Being, an idea that was first proposed by Aristotle in the 4th century B.C. 5. The universe was perceived as being part of the Grand Design. * Archbishop James Ussher calculated that the world had been created in 4004 B.C. 6. The belief that the earth was very young, coupled with the notion of fixity of the species, was a significant obstacle to the development of evolutionary thought.
III. The Scientific Revolution
F. In Europe, the scientific revolution developed as fundamental ideas of the Earth & the biological world were overturned. However, in Arabia & India, scholars developed concepts of planetary motion centuries earlier. 7. In 1514, Copernicus argued that the solar system was heliocentric. 8. In the 1600s, Galileo Galilei restated Copernicus concepts & was sentenced to house arrest. 9. The laws of physics, motion, & gravity were developed in the 17th century. 10. Europeans began to investigate nature as though it was mechanistic & sought to discover its fundamental natural laws. IV. Precursors to the Theory of Evolution
G. The first step to understanding the many forms of organic life was to list & describe them. 11. John Ray (1627-1705), an ordained minister at Cambridge University first recognized that groups of plants & animals could be distinguished from other groups by their ability to produce offspring. * These groups were termed species.
b. Ray also coined the term genus, noting that similar species could be grouped together....