Download Bean Frequency

Lab Requirements:
1. Title
2. Purpose
3. Answers to the Pre-lab questions
4. Data Table (with data)
5. Answers to analysis questions
Bean Frequency
Pre-lab
1. Explain the difference between genotype and phenotype.
2. What does natural selection act upon- the genotype or the phenotype of a species?
Explain your answer.
3. Explain why a population can evolve, but an individual cannot.
4. What is a gene?
5. What is an allele?
6. A species of rabbit has its fur color determined by a single gene B, where B is
incompletely dominant to b. Meaning that BB is the genotype of black fur, Bb is the
genotype for grey fur and bb is the genotype for white fur. Determine the phenotypic and
genotypic frequency for this trait for a population consisting of 48 black rabbits, 72 gray
rabbits, and 286 white rabbits.
7. Make a prediction about the habitat where the population of rabbits described above
lives. Explain your prediction.
Materials
4 meter sticks, beans (pinto, kidney, and navy), 2 forceps, 2 paper cups, timer
Procedure
1) Create a feeding area by placing the hula hoop on the ground away from other
groups (no concrete or asphalt or any trails)
2) Scatter 45 seeds (15 of each color) inside the feeding area.
3) Prepare for feeding by placing the nests on the outside edge of the feeding area.
The two birds must stand outside the feeding area during the feeding session.
4) When time begins, the birds should use the forceps to gather as much food as
possible. Beans must be placed in the nest to count as a capture.
5) When time is up (25 seconds of hunting), each bird counts the number of each
type of bean caught and reports these numbers to the recorder. The recorder uses
this information to determine the number of each color of bean remaining in the
feeding area.
6) The surviving beans produce 1 offspring each. The offspring are the same color as
the parent bean. (ex: If there are 5 white remaining at the end of the feeding
session, add 5 more white beans).
7) Record the number of each color of bean for the start of the next session. (Add the
number that remained and the new offspring.)
8) Repeat steps 3-7 for 4 feeding sessions.
Data
Start
Session
1
2
3
4
burgundy
15
white
15
Caught
speckled
burgundy
white
Remaining
speckled
burgundy
white
speckled
15
Analysis
1) In this simulation the gene for the color of the beans is represented by a single
gene where B is incompletely dominant to b, thus BB is the genotype for
burgundy beans, Bb is the genotype for speckled beans, and bb is the genotype for
white beans, Calculate the phenotypic frequency and genotypic frequency at the
start of each feeding session.
2) Did the population of beans evolve during the activity? Explain your answer using
evidence.
3) Which type of selection occurred in the population (directional, stabilizing,
disruptive)? Explain your answer.
4) Which, if any, color would be considered an adaptation in this environment?
Explain your answer.
5) Describe an environment where a different color would be an adaptation. Explain
your answer.
6) What other variations exist amongst the beans? Even those of the same color are
not identical. Identify a trait besides color that may have acted as an adaptation
for a bean in this activity. Explain your answer.