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Chapter 2. The Development of Evolutionary Theory. Evolution?. Brian Malow http://www.youtube.com/watch?v=Ohvh47vTp34&feature=related. Introduction to the Subject of Evolution. Evolution is the most fundamental of all biological processes, but one of the most misunderstood.
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Chapter 2 The Development of Evolutionary Theory
Evolution? • Brian Malow http://www.youtube.com/watch?v=Ohvh47vTp34&feature=related
Introduction to the Subject of Evolution • Evolution is the most fundamental of all biological processes, but one of the most misunderstood. • Humans evolved from a species that lived some 6-8 million years ago (mya), not monkeys or chimpanzees.
Evolution takes time; hence, the appearance of a new species is rarely witnessed (microevolutionary changes occur, however: see Chapt. 1) • The subject of evolution is controversial, especially in the U.S. because of conflicting spiritual teachings
Evolution Is a Theory • The theory has been tested and subjected to verification through accumulated evidence (and has not been disproved) • The theory of evolution has been supported by a mounting body of genetic evidence. • The theory has stood the test of time. • The theory continues to grow.
A Brief History of Evolutionary Thought • Evolutionary principles were developed in western Europe, made possible by scientific thinking dating to the 16th century. • Western science, however, borrowed ideas from Arab, Indian, and Chinese cultures where notions of biological evolution had already developed. • It was the theory that was new.
Natural Selection • Natural selection in the theory of evolution refers to genetic change or changes in the frequencies of certain traits in populations due to differential reproductive success between individuals. • The most critical mechanism of evolutionary change, first explained by Charles Darwin • Same conclusions were independently reached by Alfred Russel Wallace. • A predominant feature of European worldview was, however, that all forms of nature never changed….
Fixity of Species • The notion that species, once created, can never change. • An idea opposed to theories of biological evolution. • To challenge the idea was to challenge the perfection of God’s design.
The Scientific Revolution • Came with the discovery of the New World, introducing new ideas and challenging fundamental views about the planet. • Exposure to new plants and animals increased awareness of biological diversity.
EVOLUTIONTHE INSPIRATIONSJOHN RAY 1627-1705 • John Ray, a minister educated at Cambridge University, developed the concept of species. • He recognized that groups of plants and animals could be differentiated from other groups by their ability to mate with one another and produce offspring. • He placed such groups of reproductively isolated organisms into a single category, which he called the species.
EVOLUTIONTHE INSPIRATIONSCAROLUS LINNAEUS 1707-1778 • Carolus Linnaeus, a Swedish naturalist who developed a method of classifying plants and animals. • In SystemaNaturae, first published in 1735, he standardized Ray’s use of genus and species terminology and established the system of binomial nomenclature. • He added two more categories: class and order. • Linnaeus’ four-level system became the basis for taxonomy.
EVOLUTIONTHE INSPIRATIONSERASMUS DARWIN1731-1802 • Erasmus Darwin, Charles Darwin’s grandfather • Physician, poet, and leading member of an intellectual community in England • In a poem, expressed the view that life had originated in the seas and all species descended from a common ancestor. • Charles read his grandfather’s writings, but how much he was influenced by them is unknown.
EVOLUTIONTHE INSPIRATIONSJEAN-BAPTISTE LAMARCK 1744-1829 • Jean-Baptiste Lamarck developed a theory to explain the evolutionary process, known as the inheritance of acquired characteristics. • An example is the giraffe: having stripped the leaves from the lower branches of a tree, the animal tries to reach leaves on upper branches. • The neck becomes slightly longer. • The longer neck is passed on to offspring. France