Darwins Theory of Evolution Objectives 1.Summarize ideas from Darwins time that influenced his work. 2.Identify some key observations from Darwins voyage that led to his theory. 3.Describe the two main points of Darwins theory. Vocabulary Evolution Adaptation Descent w/ Modification Natural selection Evolution: Process by which modern organisms have descended from ancient organisms (change over time) Based on the following principles: Struggle for Existence:Struggle for Existence: Organisms generally have more offspring than resources can support Natural Variation:Natural Variation: W/in species there will be VARIATIONS in traits (due to genetic mutation & recombination) Adaptation:Adaptation: Some variations provide an advantage that increases chances of survival. Survival of the Fittest:Survival of the Fittest: Those with the adaptations are more likely to survive and reproduce Descent with Modification:Descent with Modification: Genes for beneficial adaptations are passed on & trait becomes more common in each new generation. Natural Selection = Mechanism for Evolution Charles Darwin ( ) Proposed THEORY OF EVOLUTION. 1. Descent with Modification Change in species over time. Modern organisms descend from ancient. Adaptations are acquired in response to changes in habitat Adaptation: Inherited trait that improves ability to survive & repro. 2.NATURAL SELECTION = mechanism Well suited individ. SURVIVE & REPRO. More offspring (pass genes on) Old Ideas Before Darwin Species are fixed or permanent Earth was less than 10,000 years old (and unchanging) Darwins Influences Lyell: Study of fossils, rock record, and geologic processes Earth is much older than 10,000 and Earth CHANGES. Farmers: Selective breeding can change species. Malthus: Economist (Famine & disease result when population are bigger than resourcesCompetition for resources, survival of the fittest idea) Lamarck (1800): Inheritance of Acquired Characteristics (Organisms can adapt!) Lamarcks Theory of Evolution Inheritance of Acquired Characteristics Based on 3 Ideas 1.Desire (will) to change 2.Use and Disuse 3.Passing on acquired traits Introduces idea that populations CAN EVOLVE or CHANGE (correct) Knew NOTHING about GENES/GENETICS. Sorry Lamarck: Organisms can only pass on traits encoded in DNA (not traits acquired by behavior) Darwins Observations Voyage on the BEAGLE Galapagos: Unique organisms - similar to, but different from plants on nearest mainland. Each island had some unique species. Mainland species had changed after they colonized the islands and adapted to new environments. Wrote: On Origin of Species (w/ Wallace), 1858 Unique Species of Galapagos Each island has unique species that show a relationship to one another and mainland. Peppered Moths: Natural Selection in Action Which one is best fit for the environment? What happened? Relative frequency of alleles for color changed in the gene pool for the population. Why? Change in selective pressure Evolution Is it incorrect to state that humans evolved from monkeys? Defend your answer with reasons and evidence. Evolution While this bird-shark is cool, why is it unlikely to evolve from either birds or sharks? Defend your answer with reasons and evidence. Self Quiz 1.You hear someone remark that evolution says we come from monkeys. Educate them with your response. 2. Discuss 1 influence (person) on the development of Darwins theory. Explain HOW this influence relates to Darwins EVOLUTION. Self Quiz 3.What did Lamarck get right? What did he get wrong? 4. 2 Sentence Summary: What is evolution and how does it work? Links Superbugs & Antibiotic Resistance:la_n_ htmlhttp://www.huffingtonpost.com/2013/03/06/superbug- la_n_ html Superbug & Antibiotic Resistance:resistant-superbug/#axzz2QFi4CFgThttp://fox59.com/2013/03/06/cdc-warns-hospital-patients-about-drug- resistant-superbug/#axzz2QFi4CFgT PBSs Evolution: Great Transformations Episode 2M&playnext=1&list=PL025876CC77CDD9AE&feature=resu lts_main PBSs Evolution: Extinction Episode C7F78A11F