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Learning from the Fossil Record
Grade 8 Science
Name: Jimmy Panzini
Date: January 21, 2010
Plant Genetics and Variation Investigation
PART 1: Setting Up the Investigation
Your group will germinate four plates of seeds and study the inheritance of plant color.
1. Plate 1 will contain 10 female parent seeds (P1) that contain two genes for the same plant color.
2. Plate 2 will contain 10 male parent seeds (P2) that contain two genes for the same plant color.
3. Plate 3 will contain seeds of the offspring of the parents above. (F1) Think of the pollen from P2
combining with the egg of P1 to create them.
4. Plate 4 will contain seeds of the offspring of two plants from F1 mating. (F2) Think of the pollen from
one F1 plant combining with the egg of one F2 plant to create them.
Follow the procedures below to set up the plates. Read and follow the procedures very carefully.
1. Use a ruler to draw a line 2 cm from the edge of a sheet of filter paper as shown below.
2. Write the date, your group’s class , your group’s table number, and the seed type on the paper as
shown below.
1/5/11 8Black- 2 P1
2 cm
3. Place the filter paper circle inside the lid of a petri dish.
4. Use a pipette to add water to the filter paper until it is completely saturated.
5. Drain off any excess water.
6. Place the appropriate seeds on the filter paper, somewhere above the 2-cm line.
7. When you have finished place the bottom of the dish on the lid to serve as a cover.
8. Place your group’s plates into a cup as shown on the diagram on the board- at a steep angle, with the
2-cm marked section at the bottom.
9. Pour water into the cup to a depth of about 2 cm. The water level should not reach any of the seeds
on the filter paper. If it does, remove the plate and reposition the seeds.
10. Leave the cups with their plates in the light box in the back of the room.
Over the next few days the seeds will germinate so you can observe and analyze their color.
Learning from the Fossil Record
Grade 8 Science
Name: Jimmy Panzini
Date: January 21, 2010
PART 2: Making and Analyzing Observations
1.
Record your observations below.
Mother (P1)
Father (P2)
#10 green
#0 purple
#0 green
46
0
0
#10 purple
48
Offspring (F1)
#0 green
#9 purple
0
45
Offspring (F2)
2.









#3 green
#9 purple
25
51
Use the “I see…this means…” strategy to explain each observation you made.
Purple is stronger than green.
Stronger gene= DOMINANT (capital letter)
Weaker gene= RECESSIVE (lower case)
P=purple Letters- Genotypes
p=green Physical Appearance (colors) - Phenotypes
Possibilities:
pp= Two recessive genes= Homozygous recessive
PP= Two dominant genes= Homozygous dominant
Pp= Two different genes= Heterozygous
(Mendelian) Genetics- The study of how and why we get traits
Heredity- That we get traits from our parents through reproduction
Gregor Mendel-Austrian, Monk, Pea Plants
Learning from the Fossil Record
Grade 8 Science
Name: Jimmy Panzini
Date: January 21, 2010
PART 3: Drawing Conclusions/ Incorporating Vocabulary and Concepts
a.
b.
All statements in the conclusion must be supported by observations/analysis from Part 2
and/or information you learned from previous lessons.
Add and highlight any vocabulary and concepts we discuss.
From doing our experiment in class we have learned so much about heredity and genetics. Heredity is
that we get our traits from our parents through reproduction. Genetics are the study of how and why
we get traits. In our experiment we had a mother plant (P1), a father plant (P2), a plant family (F1),
and another plant family (F2). We put the separate plants in different dishes and let them grow. When
we came and checked on them again we counted and wrote down the number of purple and green
phenotypes that there were. A phenotype is the physical appearance of the plant. In P1 there were 46
green and 0 purple. In this case the green was the dominant gene and the purple was the recessive
gene. The dominant gene is the stronger gene while the recessive gene is the weaker gene. In P2 there
were 48 purple and 0 green, in this case the purple was the dominant gene and the green was the
recessive gene. In F1 there were 45 purple and 0 green and again the purple was the dominant gene
while the green was again the recessive gene. Finally, in F2 there were 25 green and 51 purple and the
purple was the dominant gene again and the green was the recessive gene. Knowing all of this
information we were able to clearly identify what genotypes went to each plant. A genotype is the
letter or variable of each gene. The P1 plant has to have two small “pp’s” which is called a
homozygous recessive. A homozygous recessive is when there are two recessive genes. The P2 plant
has to have either a “Pp” or a “PP”. The “Pp” is called a heterozygous, which means that it has two
different genes. The “PP” is called a homozygous dominant, which are two dominant genes. The F1 we
know must also contain a homozygous dominant or heterozygous because it is all purple and the
Learning from the Fossil Record
Grade 8 Science
Name: Jimmy Panzini
Date: January 21, 2010
purple is the dominant gene. The F2 has to be the heterozygous gene because it is a combination of
purple and green plants. This shows us a lot about heredity and genetics and those things throughout
the family can dramatically change to what you think it cannot be. The person who actually
discovered this was Gregor Mendel. Gregor Mendel was Austrian and he was also a monk. He made
this discovery with pea plants and ever since then scientists are able to understand about genetics
and heredity.