1. Mendel and His Peas

2. Why don’t you look like a rhinoceros?

3. The answer to this question seems simple: Neither of your parents is a rhinoceros. But there is more to this answer than meets the eye.

4. How are traits passed from parents to offspring?

5. Do You Agree or Disagree?
Like mixing paints, parents’ traits always blend in their offspring.
If you look more like your mother than you look like your father, then you received more traits from your mother.
All inherited traits follow Mendel’s patterns of inheritance.

6. Early Ideas About Heredity
Heredity is the passing of traits from parents to offspring.
- Gregor Mendel is known as the father of genetics — the study of how traits are passed from parents to offspring.

7. May Be More Complicated Than You Think!
-You might have curly hair, while both of your parents have straight hair. -You might have blue eyes even though both of your parents have brown eyes. HOW DOES THIS HAPPEN?!

9. Gregor Mendel (1822-1884) The Father of Genetics Mendelian Genetics
4/19/2017
Gregor Mendel ( )
The Father of Genetics
This has been modified from the original ppt Oct. 2011
copyright cmassengale

10. Gregor Johann Mendel Austrian monk
Mendelian Genetics
4/19/2017
Gregor Johann Mendel
Austrian monk
Studied the inheritance of traits in pea plants
Developed the laws of inheritance
Mendel's work was not recognized until the turn of the 20th century

12. Mendel's Experimental Methods
Mendel studied genetics by doing
controlled breeding experiments with
pea plants.
There are two types of pollination:
self-pollination
cross-pollination

13. Think-Pair-Share
What do you think the difference is between self-pollination and cross-pollination?

14. Self Pollination

15. Mendel's Experimental Methods (Con)
When a true-breeding plant self-pollinates, it always produces offspring with traits that match the parent.
Mendel cross-pollinated pea plants himself and recorded the traits that appeared.

16. Cross-Pollination
Gregor removed the anthers of the plants to make sure they did not self-pollinate.

17. Mendel’s Results
Once Mendel had enough true-breeding plants for a trait he wanted to test, he cross-pollinated selected plants.
Plants are called hybrids if they come from true-breeding parent plants with different forms of the same trait.

18. He Studied:
- seed shape
- plant height
flower color
7 characteristics

19. First Generation Crosses
Purple Flowers + White Flowers =
ALL PURPLE
Look on page 407 in textbook.

20. Second Generation Hybrid Crosses
Mendel also cross-pollinated hybrid plants.
He observed that offspring of hybrid crosses always showed traits in a 3:1 ratio.

21. Second Generation Hybrid Crosses

22. Mendel’s Results (Cont)
Mendel recorded traits of offspring from many hybrid crosses.

23. Mendel’s Conclusions
Mendel concluded that two factors, one from each sperm and one from each egg, control each inherited trait.

24. Mendel’s Conclusions (cont)
A dominant trait is a genetic factor that blocks another genetic factor.
A recessive trait is a genetic factor that is blocked by the presence of a dominant factor.

25. Review Question 1
What method did Mendel use to select which plants pollinated other plants?
True breeding
Self-pollination
Cross- pollination
bees

26. C

27. Review Question 2
What is the approximate ratio of dominant to recessive expression when both parents are hybrid?
1 : 1
2 : 1
3 : 1
4: 1

28. C

29. Class Work What is the difference between genetics and heredity?
2) Describe Mendel’s first set of experiments.
3) Describe Mendel’s second set of experiments.
4) Why do you think Mendel chose to study pea plants?
5) In cats, there are two types of ears: normal and curly ears. A curly-eared cat mated with a normal-eared cat, and all of the kittens had curly ears. Are curly ears a dominant or recessive trait? Explain.