1 Apply Concepts How would Hutton and Lyell explain the formation of the Grand Canyon 2 Review What is an acquired characteristic and what role did Lamarck think they played in evolution 3 Review What is artificial selection Infer Could artificial selection occur without inherited variation- explain 4 Draw conclusions How did Malthus influence Darwin Writing Imagine you are Malthus in the year 1798. Write a newspaper article that explains your ideas about the impact of a growing population on society and the environment CH 16 DARWIN’S THEORY OF EVOLUTION 16.2 Ideas that shaped Darwin’s Theory Hutton and Geological Change Recognized the connections between geological processes and geological features Some rocks form very slowly, as sediments build up and are squeezed into layers Mountains, in turn, can be worn down by rain, wind, heat, and cold Earth is much older than a few thousand years. Lyell’s Principles of Geology Uniformitarianism Idea that the geological processes today are the same ones that shaped Earth millions of years ago Lyell argued that Earth was much, much older than a few thousand years. An Ancient, Changing Earth Hutton and Lyell concluded that Earth is extremely old and that the processes that changed Earth in the past are the same processes that operate in the present. Helped Darwin Witnessed a earthquake that lifted a stretch of shoreline 3 meters out of the sea with mussels and other sea animals clinging to it Darwin observed fossils of marine animals in mountains thousands of feet above sea level. Lamarck’s Evolutionary Hypotheses Organisms could change during their lifetimes by selectively using or not using various parts of their bodies Individuals could pass these acquired traits on to their offspring. Black-necked stilt could have acquired long legs because it began to wade in deeper water looking for food. As the bird tried to stay above the water’s surface, its legs would grow a little longer It acquired longer legs. Darwin wasn’t the first to suggest species could change over time His grandfather Erasmus Patrick Mathew came up with ideas of Natural Selection in 1831 Published in “Naval Timber and Arboriculture” “Anyhow one may be excused in not having discovered the fact in a work on ‘Naval Timber’” Darwin. Evaluating Lamarck’s Hypotheses We know that Lamarck’s hypotheses were incorrect in several ways Organisms don’t “strive” to get better Traits acquired by individuals during their lifetime cannot be passed on to offspring Or can they Bacteria and recombinant DNA. Population Growth Malthus wrote on human overpopulation The rate of population increase was greater than the rate of food increase Eventually there will be more humans than the amount of room and food needed to support everyone. Helped Darwin Darwin applied this idea to his own data- most species have a high reproductive potential (maple trees and helicopters, fish laying thousands or millions of eggs) but not all individuals reproduce let alone survive. When Darwin realized that most organisms don’t survive and reproduce, he wondered which individuals survive…and why? Artificial Selection Nature provides the variations, and humans select those they want or find useful Plant and animal breeders Over time this would produce trees with even bigger fruit and cows that gave even more milk. Helped Darwin Darwin put artificial selection to the test by raising and breeding plants and fancy pigeon varieties. Darwin had no idea how heredity worked or what caused heritable variation He did know that variation occurs in wild species He recognized that natural variation provided the raw material for evolution.