GE70B Midterm Review

GE70B Midterm Review - GE70B Winter Quarter 2010 M idterm...

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Unformatted text preview: GE70B Winter Quarter 2010 M idterm Review Lecture 1: Biological (or organic) evolution: change in the properties of groups of organisms over the course of generations. The changes must be passed via genes from one generation to the next. Individuals do not evolve. Populations or species do. Charles Da rwin provided a mechanism: 1. More individuals are produced than can survive. Consequently 2. There is a struggle for existence, and because 3. Individuals vary in features that influence their survival and reproduction (no to individuals are exactly the same, and some will do better than others i.e. natural selection), 4. There will be evolution if those features that favor some individuals over others are heritable. Darwin introduced several new ideas including: natural selection, population thinking, and chance GENOTYPE : the set of genes possessed by an individual organism, or the genetic composition at a specific locus. P HENOTYPE : the morphological, physiological biochemical, behavioral and/or other properties of an organism manifested throughout its life. CHROMOSOME : DNA-histone thread found in the nucleus of the cell. GENE : fundamental unit of heredity; segment of DNA that codes for some function or set of related functions. ALLELE : one of two or more forms of a gene that arise by mutation and occupy the same locus on homologous chromosomes. Alleles may be dominant or recessive. Dominant alleles are always expressed, Recessive alleles are only fully expressed when not paired with a dominant allele. PP = homozygous dominant pp = homozygous recessive Pp = heterozygous Mendel demonstrated: 1. Principle of segregation- pairs of alleles segregate into separate gametes, and then are rejoined at fertilization. 2. Principle of dominance- expression is not a blending but rather re ects dominance. 3. Principle of independent assortment- alleles for different traits are passed independently. Lecture 2: Seven major lines of evidence for evolution: 1) Direct Observation: a. Industrial Melanism (peppered moth): camoflauge to avoid predation. Black vs. white moths. b. Pesticide Resistance (DDT): Mosquitos became resistant to DDT b/c the surviving ones bred. c. Artificial Selection (by humans): The deliberate elimination or cultivation of desirable traits by humans. Breeding of horses, corn, etc. 2) Comparative Anatomy: a. The similarities and differences in morphology (animal vs. plant forms). b. Ex: bat arms vs. car arms vs. whale arms vs. horse arms. c. Homologous : similarity due to common anscestry. 3) Embryology/Development: a. Embryos of different species develop in the same way. b. These transient structures (structures that appear early in embryos and then disappeartails in humans) suggest evolution. c. Vestigial structures (st ructures that we no longer need appendix) also are best understood as a result of evolut ion....
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GE70B Midterm Review - GE70B Winter Quarter 2010 M idterm...

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