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Semester 2, Day 10
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Agenda Complete Homework Review for Quiz Turn in Homework Take Quiz Lecture on Genotype, Phenotype, and Natural Selection Reading/Work Time
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Complete Homework 30 minutes Questions 13.1 #1-5 13.2 #1-5 13.3 #1-5 Chapter 13 Assessment #1-15, 17-21
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Review for Quiz Define: Genetic Engineering Transgenic Organism Cloning T-DNA Know the steps of what Agrobacterium tumefaciens does in nature (transformation of plant cell) Three examples of genetic engineering Where should DNA be inserted in order to affect the ENTIRE organism? Know the steps of cloning and why the lamb is a clone of the “heart” sheep.
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Turn in Homework
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Take Quiz Silence during quiz Eyes on your own paper Put pencil down when finished.
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Mendelian Genetics Gregor Mendel: Austrian monk & plant breeder. Considered the father of genetics due to his findings in breeding pea plants in 1866. Image Source: commons.wikimedia.org
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Mendelian Genetics Inheritance / Heredity: Passing of traits to the next generation. Genetics: Study of heredity. Image Source: www.biologie.uni-hamburg.de
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Mendelian Genetics Mendel’s Work Mendel determined there must be 2 forms of a trait in pea plants alleles! Same Trait: Color Different Alleles: Yellow or Green Also said the trait seen in F 1 = dominant, while masked (hidden) trait in F 1 = recessive. Dominant Allele: Yellow Recessive Allele: Green Dominant allele is labeled with a capital letter and the recessive allele is labeled with the corresponding lower case letter. Yellow (Dominant): Y Green (Recessive): y Generation Parental (P) (Pure-Breeding) First Filial Generation (F 1 ) Second Filial Generation (F 2 ) x YellowGreen All Yellow 6022 Yellow: 2001 Green = 3:1
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Mendelian Genetics Genotype: the organism’s allele pair Zygosity: the similarity of alleles for a trait Phenotype: observable characteristic of allele pair Homozygous Dominant Genotype Phenotype Heterozygous Genotype Phenotype Homozygous Recessive Genotype Phenotype Example Y = yellow pea color y = green pea color GenotypeZygosityPhenotype Y Homozygous Dominant Yellow Y y Heterozygous Yellow yy Homozygous Recessive Green “Same”“Dominant Alleles” “Same”“Recessive Alleles” “Different Alleles” Y Y = “Dominant” “Dominant” = Yellow “Yellow” “Yellow” Y y = “Dominant” “Recessive” = Yellow “Yellow” “Green” (Dominant allele masks recessive allele) y y = “Recessive” “Recessive” = Green “Green” “Green” (No dominant allele to mask recessive)
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Evolution Change in a group of organisms over many generations CANNOT OCCUR IN AN INDIVIDUAL! 5 Mechanisms of Evolution: Natural Selection Mutations Gene Flow Genetic Drift Nonrandom Mating
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Darwin Father of Natural Selection Sailed to the Galapagos Islands Each island: unique finch species Hypothesis: new species can appear gradually through small changes over time Artificial Selection: pigeon breeders exaggerate traits over time.
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Evolution Organism: living individual Need water, food, and a place to live Fitness: ability to survive and reproduce (tall vs. short)
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Natural Selection Species: group of similar organisms capable of interbreeding (mules are not a species) Individual: single organism in a species Population: many of those individual in same place
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Natural Selection Some are better equipped for survival than others. Those less equipped die and don’t reproduce. Over time, “good” traits “build up” until we have a new species (can’t breed with previous generations)
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Basic Principles of Natural Selection 1 – Variation Individuals differ from one another 2 – Heritability Variations passed down 3 – Overproduction More offspring produced than can survive 4 – Reproductive Advantage Some survive and reproduce more
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Genotype vs. Phenotype Genotype: The allele pair Phenotype: What you see GenotypeZygosityPhenotype B Homozygous DominantBrown B bHeterozygousBrown b Homozygous RecessiveGreen
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Types of Natural Selection 4 Types Stabilizing Selection Directional Selection Disruptive Selection Sexual Selection
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Natural Selection Stabilizing Selection Example: Human Birth Weight Average is most “fit”, extremes are selected against
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Natural Selection Disruptive Selection Example: Bunnies Both extremes are most “fit”, average is selected against
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Natural Selection Directional Selection Example: Giraffes One extreme is most “fit”, other extreme is selected against
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Natural Selection Sexual Selection Example: Peacocks and Antelopes Traits that give an organism a better chance at mating get passed on more to later generations Peacocks: prettier feathers to attract females Antelopes: fiercer fighting to obtain males
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Reading/Work Time Cornell Notes: Pages 392-397 (stop BEFORE “Adaptations: Evidence for Evolution”) Pages 404-409 (stop BEFORE “The Evolution of Species”) Questions: 15.1 #1, 5 15.2 #1 Chapter 15 Assessment #2, 6, 9, 11, 16, 18-20
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