How Does Chance Influence Inheritance?

Frank Castillo
1994 Woodrow Wilson Collection

Objectives:

Materials:

Student Work Sheet:

1. If each container represents a set of genes from one parent, what could each bean really represent? _________________________________________________________

2. Take one bean from each box at the same time, and lay the pairs in rows assigned: red-red, red-white, white-red and white-white. Why must a bean be chosen from each box? _________________________________________________________________

3. After each drawing from the containers, count the beans in each row and record the selected combinations in the table presented below. _________________________________________________________________

   How many combinations are possible using two kinds of beans? ______________

   What accounts for the variation in offspring represented by the pairs of genes? ___________________________________________________________________

NUMBERS OF PAIRS OF BEANS IN:
	RED-RED	RED-WHITE	WHITE-RED	WHITE-WHITE	TOTAL
Trials
#1
#2
#3
#4
#5
#6
#7
#8
#9
#10
#"
#"
#"
#100

Summary And Conclusion:

You would expect to have 25; 25; 25; 25 for each gene pair combination, if you were drawing from the 100 beans in the container. What was you percentage of combinations for each pair? Ask your teacher if these were consistent with what was expected.

Questions:

1. Why is it necessary to have so many beans in each container? ___________________________________________________________________
   ___________________________________________________________________

2. Why is it necessary to select so many pairs? ___________________________________________________________________
   ___________________________________________________________________

3. What are the chances of selecting a gene pair with the same color? ___________________________________________________________________
   ___________________________________________________________________

   With a different color? _______________________________________________

4. What genetic principles have you discovered by this activity? ___________________________________________________________________
   ___________________________________________________________________

5. How does chance selection of genes, as shown with this bean lab, provide the basis for variation in organisms? ___________________________________________________________________
   ___________________________________________________________________

Bibliography:

Teacher's Information:

1. class introduction to theories, vocabulary words and historical background of Gregor Mendel's work with pea plants.

2. reading and discussion of the lab activity with the class.

3. implementation of activity.

4. students work on questions in cooperative teams following completion of activity.

It is recommended that the teacher maintain an effective sense of discipline in the classroom so as to avoid off-task behavior, i.e. students throwing beans around the class. It is important to pair up one capable student with one who has difficulty in understanding concepts. The activity is not difficult for students to complete and it serves as a "hook" for new information in subsequent chapters on genetics. I would also suggest that the teacher continually walk around the class to monitor student activity and assist whenever needed. This assures them that you are helpful in their completing the activity.

Students should understand the following vocabulary words:

* this could be developed as an issue related to sickle-cell disease, cystic fibrosis, etc., with emphasis on an individual who is a carrier and one who has the disease expressed.

Woodrow Wilson Index

Activities Exchange Index