Gregor Mendel conducted experiments crossing true-breeding pea plants that differed in traits like height. In the F1 generation, all offspring exhibited the dominant trait of tall plants. In the F2 generation, approximately 3/4 of offspring were tall (dominant) while 1/4 were short (recessive). Mendel realized each trait was determined by inherited factors, now called genes, that are transmitted from parents to offspring.

1. U4. HEREDITY
Section 1: Mendel and his Peas

2. Heredity

3.  Heredity: The transmission of genetic
characters from parents to offspring

4. Offspring

5.  Offspring: the immediate descendant or des
cendants of a person, animal, etc; progeny

6. Trait and
Characteristic

7.  A characteristic is a feature that has different
forms in a population. The different forms are
traits
Hair Color
Black Color Blonde Color Ginger Color

8. True-breeding

9.  True-breeding: A kind of breeding in which the
parents with a particular traits produce
offspring only with the same traits.

10. Sexual Reproduction in Plants
Female (♀)
sexual organs
Male (♂)
sexual organs

11. Mendel’s first
crosses
 The F1 generation is a
combination of 2 different
true-breeding plants
 First generation (F1)
produced only TALL plants
 The second generation (F2 )
produced tall and short
plants
 Mendel found that the
approximately 3 dominant
to 1recessive ratios showed
up consistently.
short trait
Tall trait

12. Trait and
Characteristic

13. Vocabulary
HEREDITY
Processes by which particular
characteristics are transmitted from
parents to their offspring.

14. Vocabulary
OFFSPRING
The immediate descendant or
descendants of a person, animal, etc;
progeny.

15. Vocabulary
INHERIT
To receive (a position, attitude,
property, etc) from a predecessor

16. Vocabulary
TRAIT
A trait is a specific characteristic of
an organism

17. Time for Questions
What step did Mendel take to be
sure that his pea plants cross-
pollinated?.

18. Time for Questions
What step did Mendel take to be sure
that his pea plants cross-pollinated?
a. He used two white plants.
b. He removed the anthers of one plant.
c. He added anthers to both plants.
d. He used plants that were not true
breeding.

19. Time for Questions
The one thing that Gregor Mendel
realized could explain the results of
his experiments was that

20. Time for Questions
The one thing that Gregor Mendel realized could
explain the results of his experiments was that
a. the traits were appearing at random.
b. the male traits were always the dominant ones.
c. each trait had two sets of instructions, one from
each parent.
d. his important research would open the door to
modern genetic

21. Time for Questions
What did Mendel discover about
recessive traits

22. Time for Questions
What did Mendel discover about recessive traits?
a. Recessive traits reappear in the second
generation.
b. Recessive traits disappear altogether.
c. Recessive traits never appear in the second
generation.
d. Recessive traits become dominant.