Names ___________
_________________
_________________
_________________
Understanding Mendel’s Model
Genes are passed on to offspring by their parents. The genes determine the traits
of the offspring. Which traits the offspring will have depends upon which genes they get
from their parents. Some parents may have only kind of gene for a trait such as flower
color, but have two genes of that kind (1,1) or (2,2.) Other parents may have two
different genes for flower color (1,2.) Which genes the offspring will get then depends
on chance.
Violet color for flowers in peas is dominant over white color flowers in peas.
You have 8 gene cards, four for violet flower color (1) and four for white flower color (2)
in peas. You will only use 4 gene cards at a time in this activity.
(1,1) crossed with (1,1)
1. Get the paper bag marked male. Put two violet (1) genes in the bag. This will
represent a male parent with 1,1 violet flower color. Get the paper bag marked
female. Put two violet (1) genes in the bag. This will represent a female parent
with 1,1 violet flower color.
What genes for flower color do both parents have? List both color and numbers.
______________________
Take 1 gene card out of each bag without looking into the bags. Put the two genes
together to represent an offspring.
What flower color does the offspring have? List both color and numbers.
____________________________
Is any other flower color possible? ___________________________________
(2,2) crossed with (2,2)
2. Get the paper bag marked male. Put two white (2) genes in the bag. This will
represent a male parent with 2,2 white flower color. Get the paper bag marked
female. Put two white (2) genes in the bag. This will represent a female parent
with 2,2 white flower color.
What genes for flower color do both parents have? List both color and numbers.
______________________
Take 1 gene card out of each bag without looking into the bags. Put the two genes
together to represent an offspring.
What flower color does the offspring have? List both color and numbers.
____________________________
Is any other flower color possible? ___________________________________
1
(1,1) crossed with (2,2)
3. Get the paper bag marked male. Put two violet (1) genes in the bag. This will
represent a male parent with 1,1 violet flower color. Get the paper bag marked
female. Put two white (2) genes in the bag. This will represent a female parent
with 2,2 white flower color.
What genes for flower color does each parents have? List both color and numbers.
______________________
Take 1 gene card out of each bag without looking into the bags. Put the two genes
together to represent an offspring.
What flower color does the offspring have? List both color and numbers.
____________________________
Is any other flower color possible? ___________________________________
(1,2) crossed with (1,2)
4. Take out the genes from the male and female bags. Now put one gene for violet
color (1) and one gene for white color (2) in the male bag. Put one gene for violet
color (1) and one gene for white color (2) in the female bag. Take 1 gene card out
of each bag without looking.
What is the flower color of the offspring? List both color and numbers. __________
Is any other flower color possible?____________________________________
If so, what other colors are possible? List both color and numbers. __________
Form offspring from the bags and record their flower color in the table for a cross
between (1,2) and (1,2) using tally marks. Do this 50 times.
Table (1,2) x (1,2)
Flower Color
Tallies and Total
Percent (multiply the
total by 2)
Violet (1,1)
Violet (1,2)
White (2,2)
What is the ratio of the trait that appeared most often to the trait that appeared the least
often? (Add both violets together to get the total number of violet flowers.)___________
(1,2) crossed with (2,2)
5. Take out the genes from the male and female bags. Now put one gene for violet
color (1) and one gene for white color (2) in the male bag. Put two genes for white
color (2) in the female bag. Take 1 gene card out of each bag without looking.
What is the flower color of the offspring? List both color and numbers. ___________
Is any other flower color possible?____________________________________
If so, what other colors are possible? List both color and numbers. ______________
2
Form offspring and note their flower color as before. Make 50 trials. Enter your
results in the table for a cross between (1,2) and (2,2)
Table (1,2) x (2,2)
Flower Color
Tallies and Total
Percent (Multiply the
Total # by 2)
Violet (1,1)
Violet (1,2)
White (2,2)
What is the ratio of the trait that appeared most often to the trait that appeared the least
often? (Add both violets together to get the total number of violet flowers.)__________
(1,1) crossed with (1,2)
6. Take out the genes from the male and female bags. Now put one gene for violet
color (1) and one gene for violet color (1) in the male bag. Put one gene for violet
color (1) and one gene for white color (2) in the female bag. Take 1 gene card out of
each bag without looking.
What is the flower color of the offspring? List both color and numbers. ___________
Is any other flower color possible?____________________________________
If so, what other colors are possible? List both color and numbers. _______________
Form offspring from the bags and record their flower color in the Table 1 on the next
page using tally marks. Do this 50 times.
Table (1,1) x (1,2)
Flower Color
Tallies and Total
Percent (Multiply the
total number by 2)
Violet (1,1)
Violet (1,2)
White (2,2)
What is the ratio of the trait that appeared most often to the trait that appeared the least
often? (Add both violets together to get the total number of violet flowers.)___________
3
Violet
(1)
Violet
(1)
Violet
(1)
Violet
(1)
White
(2)
White
(2)
White
(2)
White
(2)
4