Biology Lessons Part 2: Population Biology


 Lesson 2.5: How Do Organisms Reproduce?

Knowledge Mapping Exercise

Grade Level

Prospective and Practicing K-8 Teachers; may be adapted for use in elementary classes.


Approximately 3 hours.


Once you have completed these exercises you should be able to:
   1. Design a Knowledge Mapping lesson involving the SemNet® software and using a starter net.

 Exercise 1

Preparing a Knowledge Mapping Exercise for High School Students

 Introduction Imagine that you have been invited to teach this lesson, "How Do Organisms Reproduce? (Meiosis)," to a class of high school biology students. Assume they are familiar with knowledge mapping using SemNet. You are going to develop an exercise that that will help reinforce the students' knowledge and understanding of the meiotic process. To do this, perform the following steps.
  1. The first thing is to determine the goal of the lesson. Perhaps the most challenging thing to understand about meiosis is how each stage flows into the next and what happens in each stage. The goal, then, is to prompt students to organize ideas and construct a model of these dynamic events.
  2. The second step is to determine the assignment. An idea is to have your students to construct a net describing each of the stages of meiosis in succession, with key distinguishing characteristics of each stage. They will link each stage in succession by the relation, follows / followed by.

The third step is for you to construct, revise and polish a net to illustrate what you think would be an "ideal response." Doing the task yourself helps you review the lesson material, understand what is involved with the activity, discover what might be confusing, and how to structure the guidelines for your class.

Our "ideal" net can be downloaded here.

  4. To provide some assistance for your students, you will give them a "starter" net with accompanying instructions. The "starter" net will contain all of the concepts and relations they need but no instances. You will give the students a list of the relations and concepts in the net on a separate sheet of paper.
  5. First generate a list of the relations used in your "ideal response net" to be used as a handout for your students. Open up your net in SemNet. On the File menu in SemNet, choose Export. Export your all relations (in text format) in Creation order. This function will create a text file containing the information about relations from your net, which will appear on your desktop.
  6. Open the saved text file in a word processing program such as Microsoft Word or Clarisworks. Delete the first two header lines. Select all the lines containing relation names and convert from text to table. This will organize all the information in table format. Save.
  7. Keep the first four columns, which include the item number, the first relation name, the second relation name, and the clock settings. Select and delete the fifth column (number of times the relation was used), sixth, and seventh columns.
  8. Adjust the width of the remaining columns so each row appears in one line with minimum space following it.
  9. Select the first row of the table by dragging your cursor along it and insert a new row above it. Put bold-faced headings in this row as follows: #, 1st Relation Name, 2nd Relation Name, and Clock Setting. An example is shown below (Table 1).
Table 1. Relations in Creation order example (from "2.5d Meiosis KM Exercise Net").
# 1st Relation Name 2nd Relation Name Clock Setting
1 has stage stage of 6/10
2 followed by follows 3/9
3 has part part of 6/12
4 includes process process included in 8/2
5 same as   2
6 has characteristic characteristic of 4/10
7 occurs at site site in which occurs 2/8
8 has definition definition of 10/4
9 has type type of 7/12
10 compoosed of component in 4/10
11 stage in which find occurs in stage 6/1
12 contrasts with   10
13 produces produced by 4/8
14 has result results from 4/10
  10. To generate a table of concepts, return to your semantic network and choose Export on the File menu again. This time export Concepts (in text format) in order of embeddedness.
  11. Open the concept text file in a word processing program such as Word or Clarisworks. As before, delete the first two header lines. Select all the lines containing concept names and convert from text to table. This will organize all the information in table format having five columns. Save.
  12. Delete all columns but the first two (item number and concept name). Select each column one at a time by clicking on the top and delete it. Adjust the width of the remaining two columns so each row appears in one line with minimum space following it.
  13. The embeddedness order arranges concepts according to their relative importance in your net. Decide on a cut-off point so you can give your students a table of the MAIN IDEAS (those near the top of the list and more central to the net) and another table of DESCRIPTORS (concepts at the bottom of the list, ).

Add a row at the top of the first table and put the labels, # and MAIN IDEAS, at the top of the columns in boldface.

Table 2. Example List of 25 Main Ideas (from "2.5d Meiosis KM Exercise Net").
1 meiosis
2 replicated chromosome
3 early prophase I
4 late prophase I
5 metaphase I
6 interphase II
7 prophase II
8 metaphase II
9 telophase I
10 cytokinesis I
11 anaphase I
12 interphase I
13 unreplicated chromosome
14 anaphase II
15 S stage
16 telophase II
17 crossing-over
18 DNA synthesis
19 tetrad
20 G2 stage
21 gamete
22 G1 stage
24 eukaryotic cell
26 centromere
30 cytokinesis II


Add a row at the top of the second table and put the labels, # and DESCRIPTORS, at the top of the columns in boldface.

Table 2. Example List of 25 Main Ideas (from "2.5d Meiosis KM Exercise Net").
23 one round of DNA replication
24 eukaryotic cell
25 two rounds of cell division
27 2 chromatids
28 2 identical DNA helices
29 chromosomes condense
31 chromosomes line up
32 spindle fibers begin to form
33 homologous chromosomes pair up
34 nuclear membranes form
35 chromosome replication
36 centrioles move to opp. poles
37 spindle fibers attach to chrom
38 extended chromosomes
39 nuclear membrane breaks down
40 centromeres split
41 chromosomes uncoil
42 chromatids migrate to poles
43 chromatids separate
44 no new DNA synthesized
45 single DNA helix
46 chromosomes do not replicate
47 breaking/joining chromosomes
48 new genetic recombinations
49 haploid
50 2 haploid daughter cells
51 exchange of genetic material
52 pinching of cell into 2
53 homologous chroms move to poles
54 egg
55 pollen
56 sperm
57 spindle forms
58 homologous chromosomes separate
59 pair of homologous chromosomes
60 four haploid daughter cells
61 preparation for cell division
62 each daughter cell unique


Now create a starter net for your students. The starter net contains all the concepts and relations that are included in the three tables you have created, but none of the instances. To create the starter net, go to your "ideal response" net and on the File menu, select Save a Portion As. Save the Concepts and Relations but NONE of the Instances. Call this new net the "2.5d Meiosis KM Starter Net."

Our "2.5d Meiosis KM Starter Net" is shown below.


Finally, you are ready to assemble your assignment for your students. Below are suggestions for written instructions.

a. Work in groups of three or four students.

b. Find the starter net named ___ (e.g., 2.5d Meiosis KM Starter Net) at this location (e.g., on a server, on a diskette, on their desktop).

c. Open the starter net by double clicking on it. Choose Save As from the File menu and name the net Meiosis followed by the initials of each member of the group, as in "Meiosis,Initials1.Initials2.Initials3.Initials4".

d. The starter net includes "X" concepts (e.g., 67) and "X" relations (e.g., 14). You job is to connect these ideas into a well-organized, interconnected web. Connect each stage in meiosis to its successive stage with the relation "followed by".

e. You must use all MAIN IDEAS. Use most but not necessarily all DESCRIPTORS. Try to use only the relations provided in the starter net.

f. Begin by working with your group to define each relation. Type the definition in the text box associated with each relation (Text For "relation" in the Relation menu).

g. Construct your network. Add new concepts or relations as needed. Save frequently.

h. When you are finished constructing, revising and polishing, turn in your work. (You may ask your students to submit an electronic copy or printouts of such features as About Net, Relations in Creation Order, and Concepts Graphically 6 per page with compact screen.)