Transcript Evolution
Evolution: http://www.youtube.com/watch?v=faRlFs YmkeY&safe=active (Simpson’s 1.5 minutes) CHANGE OVER TIME Leaves on trees change color and fall over several weeks Mountain ranges erode over millions of years. Over a large number of years, evolution produces tremendous diversity in forms of life. A change in ethnic genealogy can happen in a small number of years. Fact or Theory ??? “Evolution Occurs “ (fact) “How Evolution Occurs “ (theory) Different Types of Evolution: • Biological (Organic) – changes in biodiversity over time • Chemical – how life arose; how the first cell came to be • Geological- changes in the earth over time; continental drift; creation of new rock layers Emergence of Evolutionary Thought: • From early on, humans have asked themselves how so many different living things have come to be • The search for the answer to this question has led to many different theories on evolution: Special Creation (religious – species are fixed and do not change) Descent with Modification (scientific – all life comes from a common ancestor) A combination of the two Decent with Modification: Video - Isn’t Evolution Just a Theory? • http://www.youtube.com/watch?v=85diEXbJBIk&safety_mod e=true&persist_safety_mode=1&safe=active (PBS 6:07 min) Also on SeaGate #1 Charles Darwin (1809-1882) • Many of today’s ideas about evolution are based on Darwin’s Theory • Drafted manuscripts of his theory in the 1840’s but did not release them due their controversial nature (it was in direct conflict with the teachings of the Bible!) • Published his famous book The Origin of Species in 1859 History of Evolutionary Thought • Darwin was not the first to try to explain how organisms might have changed over time • Based his theory on: • Observations he made as a Naturalist during many voyages on The Beagle • Results of selectively breeding farm animals, plants and pets • The work of other scientists, geologists & mathematicians • James Hutton (1726-1797) and Charles Lyell (1797-1875) studied the forces of wind, water, earthquakes and volcanoes. They concluded the earth is very old and has changed slowly over time due to natural processes. • Erasmus Darwin (1731-1802) suggested that competition between individuals could lead to changes in species. (He also was Charles Darwin’s grandfather.) • Jean Baptiste Lamarck (1744-1829) proposed a mechanism by which organisms change over time. He hypothesized that living things evolve through the inheritance of acquired characteristics. • Thomas Malthus (1766-1834) observed that human populations cannot keep growing indefinitely. If the birth rate continued to exceed the death rate, eventually humans would run out of living space and food. Famine, disease and war prevented endless population growth. Basis of Darwin’s Theory • All living things are derived from pre-existing forms by a series of changes that have taken place over immense periods of time • All living things thus have a common ancestry • Life started out simple, and gradually became more complex • Called his theory Natural Selection • Which basically means that the environment that an organism lives in, “chooses” which characteristics are best suited for survival and reproduction in that environment Alfred Russell Wallace (1823-1913) • proposed a theory of evolution by natural selection similar to that of Darwin. • He wrote a paper and sent it to Darwin to review. This spurred Darwin on to finally agree to the release of his theory. • In 1858 Charles Lyell presented Darwin’s 1844 essay and Wallace’s paper to the public. • Wallace’s name now often accompanies Darwin’s when in comes to the theory of Natural Selection Video – Who was Charles Darwin? • http://www.youtube.com/watch?v=vmphlbRhLu8&feature=relate d&safety_mode=true&persist_safety_mode=1&safe=active • (PBS 6:39) • Also on • Seagate #2 The Galapagos Islands • Darwin’s studies of the species he collected helped him develop his theory http://science.d iscovery.com/vi deos/100greatestdiscoveriesshorts-naturalselection.html 2:34 Bill Nye Darwin and Biodiversity • Darwin noticed that the animals on the Galapagos had adapted to their environments, and were similar yet different to their relatives living on mainland South America • Darwin also noted that the diversity of living species was far greater than anyone had previously known!! Galapagos Biodiversity • Darwin observed many unique plants and animals including: • Giant Tortoises • Marine iguanas • Gulls • Boobys (birds… not … including a blue footed one) • Penguins (including the world’s smallest) • Flightless Cormorants Darwin’s Finches • The 13 different species of Finches from the Galapagos Islands that Darwin studied • Darwin suggested that all 13 finch species evolved via adaptive radiation and descent with modification from one species that occupied the SA mainland • Each finch in the Galapagos evolved to be able to occupy different habitats and eat different foods • http://www.youtube.com/watch?v=l25MBq8T77w&feature=related&safety_mode=true&persist_safety_mode=1&safe=active (David Attenborough 2:11) Also on Seagate “Galapagos Finches” THE END OF PART 1 !! Other videos on Seagate to show if time: Galapagos Iguanas Evolution in the Galapagos