Mr. AltorferScience

HereditySection 1

Mendel and His PeasPages 114 to 117

• What you will learn: (our objectives)– Explain the relationship between traits and

heredity.– Describe the experiments of Gregor Mendel.– Explain the difference between dominant and

recessive traits.

• Heredity- The passing of genetic traits from parent to offspring.– Why do you have brown eyes while both your

parents have blue eyes?– Why are you the only left handed person in

your family?– Heredity! That’s why!

Who Was Gregor Mendel?

• Gregor Mendel- – Born in 1822– He became a monk (lived in a monastery)– He studied heredity by working with pea

plants.

One of my heroes! A pea plant

Unraveling the Mystery

• Why did Mendel use pea plants?– Pea plants can self pollinate.– Peas can also pollinate other pea plants.

Characteristics vs. Traits

• Characteristics- A feature that has different forms in a population or a group.– Eye Color, Hair Color

• Traits- Different forms of a characteristic.– Blue Eyes or Brown Eyes, Red Hair or Brown

Hair

• What traits does this cat have? – Eye Color:– Hair Color:

Mendel’s Experiments

• Dominant Trait- The trait observed in the first generation when parents that have different traits are bred.

• Recessive Trait- A trait that reappears in the second generation after disappearing in the first generation when parents with different traits are bred.

Ratio’s and Mendel’s Experiments