1. Mendel and His Peas
Chapter 11
Lesson 1

2. Background The subject: pea plants Why? Reproduce quickly
Easily observed traits
Can control reproduction

3. Pollen (sperm cells) land on pistil (egg cells)
Pollination
Pollen (sperm cells) land on pistil (egg cells)

4. Self-pollination
Pollen from one plant lands on pistil from same plant.
True-breeding – results from self-pollination, offspring will have the same traits

5. Cross Pollination
Pollen from one plant lands on pistil from a different plant.

6. What Mendel Did

7. Traits Studied Flower color – purple/white Seed color – green/yellow
Seed shape – round/wrinkled

8. First-Generation Crosses

9. Second-Generation Cross

10. Mendel’s Conclusions Two genetic factors control every trait.
One trait comes from sperm, one trait comes from egg.

11. Discovered Dominant and Recessive Traits
Purple is dominant trait – a genetic factor that blocks another genetic factor.

12. Discovered Dominant and Recessive Traits
White is recessive trait – a genetic factor that is blocked by a dominant trait.

13. Discovered Dominant and Recessive Traits
Recessive is only seen when both factors are recessive.