Download MendelsWork

Get your textbook (p. 154) and science notebook ready.
SNB page 35/ Write the title and follow the directions.
Mendel’s Work (Cornell Style notes on SNB page 37)
1. Heredity is the passing of physical
characteristics from parents to offspring.
Mendel’s Work
2. Traits are physical
characteristics that
can be passed from
parents to offspring.
3. Genetics is the study of heredity.
4. Mendel is considered the father of
genetics.
5. A new organism begins to form when male and
female sex cells join in the process called
fertilization.
Mend controlled the fertilization in pea plants.
6. A purebred organism is the offspring of many
generations that have the same traits.
.
7. Mendel’s Experiment:
P Generation – In the Parent Generation, a tall purebred
was cross with a short purebred.
.
8. 1st Generation – All of the offspring were tall.
None of the offspring were short even though one
parent was short.
.
9. 2nd Generation – Offspring occurred in the ratio
of three tall plants to one short plant..
10. The short trait
did not occur in the
1st generation,
but reappeared
in the 2nd generation.
Replicate figure 1 on textbook page 155.
Use the top half of SNB page 36.
Replicate Figure 2 on textbook page 156.
Use the bottom half of SNB page 36.
How could a short plant
come from all tall plants?
Mendel reasoned that
two factors determined
the height of a plant.
The F1 generation has
a tall factor and short
factor, so the short plant
received two short factors.
11. The factors that
determine traits
are called genes.
12. P Generation:
One parent had two tall genes.
The other parent
had two short genes.
13. F1 Generation:
All offspring have one tall and one short gene.
14. F2 Generation: Three possibilities:
• Can get a tall gene from both parents.
• Can get a tall from one
parent and a short from
the other.
• Can get a short gene from
each parent.
15 Summary:
Traits are controlled by two genes.
• One gene comes from the female parent and the
other comes from the male parent.
• One gene of a pair can hide or dominate the trait
of another gene.
• Offspring receiving two hidden or recessive genes
will have the hidden trait.