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Semester 2, Day 10

Semester 2, Day 10. Agenda. Complete Homework Review for Quiz Turn in Homework Take Quiz Lecture on Genotype, Phenotype, and Natural Selection Reading/Work Time. Complete Homework. 3 0 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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Semester 2, Day 10

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  1. Semester 2, Day 10

  2. Agenda • Complete Homework • Review for Quiz • Turn in Homework • Take Quiz • Lecture on Genotype, Phenotype, and Natural Selection • Reading/Work Time

  3. Complete Homework • 30 minutes • Questions • 13.1 #1-5 • 13.2 #1-5 • 13.3 #1-5 • Chapter 13 Assessment #1-15, 17-21

  4. Review for Quiz • Define: • Genetic Engineering • Transgenic Organism • Cloning • T-DNA • Know the steps of what Agrobacteriumtumefaciensdoes 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.

  5. Turn in Homework

  6. Take Quiz • Silence during quiz • Eyes on your own paper • Put pencil down when finished.

  7. 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

  8. Mendelian Genetics • Inheritance / Heredity: Passing of traits to the next generation. • Genetics: Study of heredity. Image Source: www.biologie.uni-hamburg.de

  9. 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 F1 = dominant, while masked (hidden) trait in F1 = 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) x Yellow Green First Filial Generation (F1) All Yellow Second Filial Generation (F2) 6022 Yellow: 2001 Green = 3:1

  10. 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 Y Y = “Dominant” “Dominant” = Yellow “Yellow” “Yellow” “Same” “Dominant Alleles” “Different Alleles” Y y = “Dominant” “Recessive” = Yellow “Yellow” “Green” (Dominant allele masks recessive allele) “Same” “Recessive Alleles” yy = “Recessive” “Recessive” = Green “Green” “Green” (No dominant allele to mask recessive)

  11. 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

  12. 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.

  13. Evolution • Organism: living individual • Need water, food, and a place to live • Fitness: ability to survive and reproduce (tall vs. short)

  14. 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

  15. 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)

  16. 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

  17. Genotype vs. Phenotype • Genotype: The allele pair • Phenotype: What you see

  18. Natural Selection works On PHENOTYPE, not on GENOTYPE!!!

  19. Types of Natural Selection • 4 Types • Stabilizing Selection • Directional Selection • Disruptive Selection • Sexual Selection

  20. Natural Selection • Stabilizing Selection Example: Human Birth Weight • Average is most “fit”, extremes are selected against

  21. Natural Selection • Disruptive Selection Example: Bunnies • Both extremes are most “fit”, average is selected against

  22. Natural Selection • Directional Selection Example: Giraffes • One extreme is most “fit”,other extreme is selected against

  23. 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

  24. 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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