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Gregor Mendel

Gregor Mendel

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Gregor Mendel

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  1. Gregor Mendel Father of Genetics Dominant/ Recessive Traits

  2. Gregor Mendel Notes: *A monk (1822-1884) *Looked after the monastery’s garden (Abbey of St. Thomas in Brno, Czech Republic) *He grew hundred of pea plants *He wanted to see if he could find a pattern in a way that certain characteristics were handed down *Considered the “Father of genetics” *Genetics is the study of heredity, or the passing on of traits from an organism to its offspring

  3. Gregor Mendel Why pea plants? *Grow and reproduce quickly *Had a variety of different characteristics

  4. Gregor Mendel What were the pea plants traits? *Height *Color of seeds *The shape of the seeds *Easily crossed and bred Point: Mendel used the Sweet Pea

  5. Gregor Mendel The pea plants had flowers *The stamen: produce pollen, which contains male sex cells, or sperm cells. *The flowers also contain the female reproductive structure, called a pistil. *The pistil produces the female sex cell or egg cell *Often self-pollinates

  6. Gregor Mendel *Mendel transferred pollen from the stamen of one flower to the pistil of another flower. *This is called cross-pollination.

  7. Gregor Mendel Mendel’s Experiments *First cross two short pea plants *Only short stem pea plants grew *Mendel stated that, since the result was what he thought it would be, new generations of plants always resemble the parent plants. *He called these short plants true-breeding plants Point: Pictures of the Brno Convent. First is in 1920.

  8. Gregor Mendel *Next he crossed two tall plants *He saw that not all the offspring ended up tall *Result, plants that are true-breeding plants and plants that did not breed true

  9. Gregor Mendel *Next he took pollen from a plant that produced tall plants and touched it to a true-breeding short plant *The initial two parent were labeled P generation *The offspring of the P generation were labeled first filial or F1 *Result was that all the plants in the F1 generation were tall

  10. Gregor Mendel *Next he let the F1 generation self pollinate, and some of the plants were short and some were tall: He called this offspring F2 *This led he to believe that there was short factors in the tall plants *We now call these factors genes: units of heredity

  11. Gregor Mendel Dominant and Recessive traits *The tall was dominant over the short *So the stronger was the trait for tall plants so it must be dominant (Usually expressed with a capital letter) *Short must then by recessive (Usually expressed with a lower case letter)

  12. Gregor Mendel Mendel *In his experiments he also studied seed shape, seed color, seed coat, pod shape, and flower position *The results were all the same: crossing two true-breeding plants with opposite traits did not result in a mixture of the traits *Only one trait appeared *But if you crossed the offspring the other trait would often reappear *Organism that has genes that are alike for a particular trait, like YY or yy are said to be pure-bred. *An organism that has genes that are different for a trait, like Yy are called hybrid