Darwin & Evolution Chapter 15-1,2

Intro to Evolution What is evolution? –Process by which modern organisms have descended from ancient organisms over a long period of time. Is evolution a fact? –No. It is a theory (well-supported testable explanation of phenomena) –Even though it is a theory, scientists do not question it due to overwhelming evidence. How does evolution occur?

Any one know Darwin? So who is this famous guy? –C–Charles Darwin Why is he so famous? –H–He contributed most to our understanding of evolution How did he do it?

Charles Darwin Wealthy family – Father, physician; Mother was daughter of James Wedgewood; Grandfather was Eramus Darwin (famous philosopher). Raised in the countryside –w–was familiar with the practice of selective breeding Indifferent Student –F–Flunked out of medical school –B–BA in Theology with undistinguished honors –F–Family concerned he was becoming an “Idle Sportsman” Collected butterflies and shot birds

HMS Beagle Charles Darwin got a job as a naturalist on the ship HMS Beagle. Starting from England in 1831, the ship traveled around the world and Darwin observed and recorded the different animals in different parts of the world. His observations led him to propose a revolutionary hypothesis about the way life changes over time EVOLUTION! So what did he observe…?

Patterns of Diversity Darwin noticed how many different types of animals there are (ex: 68 beetles in Brazil) He noticed how animals seemed well suited for their surroundings He wondered why animals live in certain places and not in others (ex: kangaroos in Australia)

Living Organisms & Fossils Darwin collected and preserved remains of ancient animals (fossils) He noticed that some fossils resembled current animals, while others were very different Where did they go? How are they related?

Galapagos Islands His most famous stop was the Galapagos Islands off the coast of S. America. Small set of islands, but with very different climates. (Dry in South, wet in North) Noticed tortoises and finches…

Pinta Island Intermediate shell Pinta Isabela Island Dome-shaped shell Hood Island Saddle-backed shell Hood Floreana Santa Fe Santa Cruz James Marchena Fernandina Isabela Tower

Darwin’s Developing Theory With new information, Darwin had to find meaning to it all. He looked to other scientists for help… He looked at the research of Hutton, Lyell, LaMarck, and Malthus (non-scientist)

Changing Earth Hutton determined that geological forces that shaped the Earth happened over a VERY long period of time (ie: Earth is OLD) Lyell explained that there are processes that change and shape the Earth (volcanoes & earthquakes)

LaMarck’s Hypothesis Lamarck proposed that by selective use of disuse of organs, organisms acquired or lost certain traits during their lifetime. These traits could be passed on to the next generation. Strive to attain perfection.

Malthus’ Population Malthus reasoned that if human population continued to grow unchecked, there would be insufficient resources and space. Darwin tied this to plants and animals. He reasoned that this did not happen with plants or animals. So what is causing their populations to be controlled? Only the _______ survive!