Mrs. Wharton

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Mrs. Whartons Class

• Mendels Work

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Mendels Experiments

• Heredity- the passing of physical characteristics
  from parent to offspring.
• Trait- Each different form of a characteristic
  (height, eye color).
• Genetics- The scientific study of heredity

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Why did Mendel study Pea Plants?

• Pea plants are usually self-pollinating, meaning
  pollen from a flower lands on the pistil of the
  same flower.
• Mendel developed a method by which he
  cross-pollinated, or crossed, pea plants.

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Mendels Experiment

• Mendel crossed two pea plants that differed in
  height. He crossed purebred tall plants with
  purebred short plants.

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• In all of Mendels crosses, only one form of
  the trait appeared in the F1 generation. However,
  in the F2 generation, the lost form of the
  trait always reappeared in about one fourth of
  the plants.
• P1 F1

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• From his results, Mendel reasoned that individual
  factors, one from each parent, control the
  inheritance of traits.

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Terms Cont.

• Fertilization-when a new organism begins to form
• Purebred-when offspring from many generations
  have the same trait
• Gene- factors control a trait
• Allele-different forms of a gene

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• An organisms traits are controlled by the
  alleles it inherits from its parents.
• Some alleles are dominant, while other alleles
  are recessive.

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• Geneticists use a capital letter to represent a
  dominant allele and a lowercase version of the
  same letter for the recessive allele.

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Mendels Results

• Parent generation (P1)- two alleles in a purebred
  tall were crossed with two alleles in a purebred
  short
• F1 generation- two hybrids were crossed
• F2 generation- resulted in purebreds and hybrids!

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Types of Traits

• Hybrid- an organism that has two different
  alleles for a trait.
• Dominant-is one whose trait that always shows up
  when the allele is present
• Recessive- a trait that is hidden every time a
  dominant allele is present.

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Mendels Results

• Mendels discovery was not recognized during his
  lifetime. In 1900, three different scientists
  rediscovered Mendels work. Because of his work,
• Mendel is often called the Father of Genetics.