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Introduction Evolution is the result of genetic changes that occur in constantly changing environments. As a basis for understanding this concept, scientists use multiple lines of evidence such Fossils, Embryological Development, Comparative Anatomy and Biogeography. New evidence from molecular biology and biochemistry are reinforcing these prior forms of evidence.
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Expectations Students should understand that the theory of evolution has multiple lines of evidence to support it. Students should understand that data from molecular evidence can be used to infer evolutionary relationships. Students should be able to use this data to create cladograms showing probable evolutionary relationships.
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California Biology Standards Addressed Students know most macromolecules (polysaccharides, nucleic acids, proteins, lipids) in cells and organisms are synthesized from a small collection of simple precursors. Students know how mutations in the DNA sequence of a gene may or may not affect the expression of the gene or the sequence of amino acids in an encoded protein. Students know how to use comparative embryology, DNA or protein sequence comparisons, and other independent sources of data to create a branching diagram (cladogram) that shows probable evolutionary relationships. Students know variation within a species increases the likelihood that at least some members of a species will survive under changed environmental conditions.
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DNA Evidence Research identified DNA as the genetic material, and identified genes as discrete elements within DNA. DNA is not perfectly copied, and rare mistakes (mutations) in genes can affect traits that the genes control. Evolutionary changes do not occur spontaneously in species; they are the product of the action of evolutionary forces on genetic variation
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Requirements Conduct research on molecular/biochemical evidence for evolution by using online resources, books, magazines etc. Prepare a 15 minute group power point presentation based on your research that presents DNA and protein evidence for evolution (maximum of 3 people in the group). The presentation should address the following questions: How do scientists use multiple lines of evidence to support a theory?How do scientist use data to infer evolutionary relationships among organisms?What types of molecular evidence are used as evidence for evolution?In addition to the molecular evidence, what other sources of evidence do scientists use for evolution?How is a cladogram created based on data from DNA or proteins? The presentation must include at least four specific examples of DNA and protein evidence for evolution. The examples and the details provided should be clearly relative to the theory of Natural Selection. You will be given two weeks for the whole project. First week you will be conducting research on the subject and the second week you will be preparing for the presentation.
Example student presentation
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Protein Evidence Proteins are basic components of all living cells and are therefore among the principal substances that make up the body. Similarities in amino acid sequences can infer evolutionary relationships among organisms.
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Learning Objectives: Students will be able to: Explain how biological molecules are used as evidence for evolutionary relationships. Construct a cladogram using data from DNA or protein sequences and correctly answer questions regarding inferred evolutionary relationships based on the cladistic analysis.
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