Evolution A. What is Evolution? 1. Several definitions video 1 video 2 a. descent with modification (Darwin) b. change in gene frequencies within a population c. All the changes that have transformed life on earth from its earliest beginnings to the immense diversity existing today

Evolution History A. Historical Development 1. Jean Baptiste Lamarck a. French biologist: proposed a theory of evolution in 1801 b. Lamarck’s Theory i. Organisms strive to improve themselves: “need” ii. Most used structures develop and less used structures are lost: “use and disuse” iii. Offspring inherited the acquired characteristics of parents History

Evolution History A. Historical Development 1. Jean Baptiste Lamarck 2. August Weismann a. Disproved Lamarck ideas by chopping of the tails of mice b. What? History

Evolution History A. Historical Development 1. Charles Darwin a. Study theology at Cambridge b. 1831 appointed naturalist aboard the ship HMS Beagle i. mission was to create maps for the British Navy c. Darwin took surveys and collected samples of plants, animals, rocks, and fossils History

Evolution History A. Historical Development 1. Charles Darwin video1 d. Most famous observations: Galapagos Islands where he spent 2 months e. Eventually sailed around the world 1831-1835 video1 video 2 History

Evolution WHY? History A. Historical Development 1. Charles Darwin f. Wrote a 200+ page thesis in 1844 outlining his theory but he did not publish WHY? g. Alfred Wallace: came to similar conclusions as Darwin in 1858 from observations collected in another area of the world h. Darwin agreed to a joint presentation with Wallace to the same scientific body. History

Evolution A. 5 ideas of Darwin’s Theory 1. Overpopulation a. Organisms produce more young than will survive b. example: Fly eggs: 250 eggs by one female in one laying Baby sea turtles Praying Mantis young from one cocoon

Evolution A. 5 ideas of Darwin’s Theory 1. Overpopulation 2. Variation a. There exists in a population a large amount of variation

Evolution A. 5 ideas of Darwin’s Theory 1. Overpopulation 2. Variation 3. Struggle for existence a. What do organisms struggle for? i. Lion attack b. Carrying Capacity: how many individuals can the environment support i. example: deer in CVNP 4. Survival of the strongest fittest a. Those that survive are the best adapted

Evolution A. 5 ideas of Darwin’s Theory 5. Natural Selection b. Individuals that survive reproduce and pass on favorable traits c. “Fittest”: those that reproduce most successful i. Differential reproductive success 5. Natural Selection a. Environmental pressures select for the best adapted b. Animated example: DDT and flies

Evolution B. People who helped Darwin 1. Thomas Malthus a. minister, economist b. Wrote: Essay on Populations c. Predicted that population would grow faster than food supply d. Lead to Darwin’s idea of struggle for existence

Evolution B. People who helped Darwin 1. Charles Lyell a. geologist b. Wrote: Principles of Geology c. Proposed the idea of Uniformitarianism i. Geological processes are constant through time ii. Challenged the prevailing thought that the earth was young iii. Darwin needed large periods of time for natural selection to work iv. Uniformitarinism provided Darwin the time element needed for his theory

Evolution B. People who helped Darwin 1. Charles Lyell/ Uniformitarianism

Evolution Natural Selection: How Evolution Works Overpopulation Genetic Variation Struggle for Existence Differential Reproductive Success Selection occurs based on: the interaction of the environment and the existing population variations the more severe the environmental pressure, the more severe the selection process

Evolution Natural Selection: the environment shapes or refines organisms adaptations Environmental Pressures resources: food, water, shelter climate: cold, hot, wet, dry predation: how does one survive?

Evolution Evidences A. Anatomical 1. Fossils a. Remains or traces left in rock strata (layers) by previous organisms (video: becoming a fossil) b. Preserved in: rocks, bogs, tar amber, ice c. Types of preserved samples: imprints, castings, and amber

Evolution Evidences A. Anatomical 1. Fossils d. Transitional records i. Classic example: the horse e. Famous fossils archeopteryx; bird or reptile?

Evolution Evidences A. Anatomical 1. Fossils e. Famous fossils Coelocanth: living fossil