Evolution of Evolution What is evolution? What was going on this time period? Who influenced the idea of evolution and how? What is natural selection? How did giraffes get such long necks?
Darwin’s Theory of Evolution • Evolution – process by which modern organisms have descended from ancient organisms…CHANGEOVER TIME • Scientific Theory – well-supported testable explanation of phenomena that have occurred in the natural world
Time Period – Most Europeans Believed… • Earth was only a few thousand years old. • The world was geometrical and regimented and will never change. • Rocks, mountains, etc were created by catastrophic events that were rarely witnessed.
Carl Linneaus If he could fine the pattern in nature he could get inside of God’s head. Classified flowers into groups based on anatomical differences Believed that the Earth was complete – no gaps, no failures Buffon Was there a separate creation for each variety? Influences
William Smith Believed that things had changed since creation Hypothesized that different animals lived at different times Georges Cuvier Used comparative anatomy to create replicas of extinct animals in which only a few fossils were found Hypothesized that animals became extinct due to catastrophes in history…BUT what about humans?? Influences
William Buckland People were not wiped out by catastrophes because they were not there. A giant flood seemed to explain all of the unexplainables. BUT why were many fish killed off? George Stroke Volcanoes and old lava being cut through by rivers was more evidence that Earth is older than the Bible predicts. George Hutton Wind and water erosion take a very long time, thus the Earth must be older than the Bible predicts. Influences
One of the first to realize that living things changed over time Hypothesis – By selective use or disuse of organs, organisms acquired or lost certain traits during their lifetime. These traits (acquired or not) could be passed down to their offspring. Over time, this process led to a change in species. Lamarck’s Evolution Hypothesis
Lamarck’s Evolution Hypothesis • Tendency Toward Perfection • All organisms have an innate tendency toward complexity and perfection. Organisms will continually change and acquire features that bring them closer to this goal. • Use and Disuse • Organisms could alter the size or shape of particular organs by using their bodies in new ways. • Inheritance of Acquired Traits • Acquired characteristics could be inherited.
Did not know how traits were inherited Did not know that an organism’s behavior had no effect on its heritable characteristics Lamarck’s Evolution Hypothesis – Incorrect in Several Ways
Charles Lyell Hypothesized that geological processes were the same as they were in past as they are now The rate at which things changed was very slow. Thus, in order for all of these slow processes to have taken place, the Earth must be older than a few thousand years. “Principles of Geology” Very influential to Charles Darwin Influences
Thomas Malthus The population had the potential to grow at a rate faster than food could be supplied. If the population kept growing at this rate, overpopulation was imminent unless reproduction and/or survival was stopped. Influences Struggle for Existence
Travels – Voyage of the Beagle • Charles Darwin sailed around the world via the H.M.S. Beagle from 1831-1836 • Collected plant and animal species • Read latest scientific books (i.e. Lyell’s Principles of Geology) • Recorded his observations and thoughts throughout journey
Observations • Many plants and animals seemed remarkably well-adapted to their environments. • Puzzled by where different species lived and did not live • If Earth could change over time, couldn’t life itself change over time? • Drew connections between Malthus’ work and his observations of plants and animals Malthus’ argument was stronger for plants and animals than for humans. • An overwhelming number of offspring die, while only a few surviving offspring succeed in reproduction. • http://www.pbs.org/wgbh/evolution/library/02/5/l_025_01.html
Artificial Selection – nature provided the variation, and humans selected those variations that they found useful Examples – farmer breeds his best livestock Darwin artificially selected pigeons to show an analogous example of how his mechanism for evolution could have worked. Reasoned that nature, given more than a million years, could surely achieve what he had artificially achieved in a short amount of time. Charles Darwin – Artificial Selection
Alfred Russell Wallace Collected beetles along the Malaysian coast and noticed variations in the beetles that corresponded with the habitat in which they were found Made some conclusions and wrote a letter to Charles Darwin Influences
Proposed natural selection (mechanism for evolution) Presented evidence that evolution has been taking place for millions of years Driven to publish his theory came from the fact that Wallace had come up with the same idea. Even though he was afraid of the Church’s reaction to his ideas he wanted to get credit for his work. http://www.pbs.org/wgbh/evolution/library/11/2/e_s_2.html Conclusions – On the Origin of Species