Presentation on theme: "Section 11-1: The Work of Gregor Mendel"— Presentation transcript:
1Section 11-1: The Work of Gregor Mendel -The Father of Modern Genetics-
21. Genetics The scientific study of heredity Every living thing contains hereditary information from its parent or parentsPassed down through generations
3Who is Gregor Mendel?THIS GUYA priest who worked in a monastery and as a high school teacherIn charge of the monastery gardenWorked with garden peasLaid the groundwork for modern genetics
42. Mendel’s Peas: Reproduction The flower creates 2 types of pollenMale: SpermFemale: Egg cellsFertilizationJoining of the male and female pollenProduces a tiny embryo encased in a seedNormally “Self Pollinating”They inherit all their genetic information from one parent
5Mendel’s Peas: Breeding 3. Each of his pea plants were “True-Breeding”If allowed to self pollinate they would produce identical offspringTypes of Pea Plants present:HeightTall PlantsShort PlantsSeed ColorGreen PeasYellow Peas
6Mendel’s Peas: The Cross Pollination Wanted to produce seeds by joining male and female cells from two different plants4. Cross PollinationCut away pollen (male) from one plant and dusting the female flower with the male pollenMade it possible to cross breed the plants and observe the offspring
8Genes and Dominance: Vocab 7. TraitsSpecific characteristic present in an organismEX: Hair Color6. HybridOff spring of crosses between parents with different genetic traitsEX: Humans5. GenesChemical factors that determine traits; passed down from parent to offspring8. AllelesDifferent forms of a geneEX: Red Hair, Brown Hair, etc.
9Genetic Terms The P (Parental) generation The original pair of plantsThe F1 (first filial) generationThe offspring of the P generationThe F2 (second filial) generationThe offspring of the F1 generation
10Mendel’s Process Studied 7 pea plant traits Seed color or plant height variationEach trait had 2 contrastsEX: Height- Tall and ShortMendel crossed plants with each of the contrasting traits and studied the offspringThis had very interesting results
11Results of P CrossWhen crossed all of the F1 generation plants displayed only one of the 2 traitsAll plants were tall!The other trait seemed to disappearWhat happened?
12Mendel’s Conclusions#1. Biological inheritance is determined by factors passed from one generation to the next9. #2 .The Principle of DominanceSome alleles are dominant and others are recessiveDominant: Trait will always be expressed10. Recessive: Trait will be expressed only in absence of dominant trait
14Mendel’s ProcessMendel wanted to see if the recessive alleles had disappeared or were still present12. Allowed the F1 plant to self pollinate and created an F2 generation with odd results.Resulted in 3 tall plants and 1 short plantThe recessive allele had reappeared!
15Results of the F1 Cross Resulted in 3 tall plants and 1 short plant The recessive allele had reappeared!13. The recessive allele accounted for roughly ¼ of the total plants…but how did this happen?Let’s look at the F1 cross in detail
16F1 Cross-Explanation14. The alleles for height segregated or separatedThe alleles for tall and short separated during the formation of the sex cells15. These sex cells are called “Gametes”This allowed the recessive trait to cross pair with another recessive and be present
1716. F1 Cross Illustrated Tt Tt T t T t TT Tt Tt tt 17.Key T- Dominant t - RecessiveTtTtTtTtTTTtTttt