The Effect of Anabolic Steroids
on
Earthworm Growth
Tim Leighton
Ben Ficklin
Ima Member
Hr. 2
Experimental Question
What is the effect of anabolic steroids on the growth of an earthworm?
Background Information
Earthworms are members of the animal phylum Annelida. Some characteristics that define them
are segmented bodies, multiple hearts, and complex circulatory and digestive systems.
Earthworms are helpful to humans in that they loosen soil enabling plant roots (especially crops)
to better develop.
Anabolic steroids are drugs that mimic the effects of the male hormone testosterone. They
increase protein synthesis within cells, which results in the buildup of cellular tissue (anabolism),
especially in muscles. Anabolic steroids also have androgenic and virilizing properties, including
the development and maintenance of masculine characteristics such as the growth of the vocal
cords and body hair. The word anabolic comes from the Greek anabolein, "to build up", and the
word androgenic from the Greek andros, "man" + genein, "to produce".
Some health risks can be produced by long-term use or excessive doses of anabolic steroids.
These effects include harmful changes in cholesterol levels (increased low-density lipoprotein
and decreased high-density lipoprotein), acne, high blood pressure, liver damage, and dangerous
changes in the structure of the left ventricle of the heart.
The use of anabolic steroids in sports and bodybuilding is controversial, because of their adverse
effects and the potential to gain an advantage. This is considered "cheating." Their use is
referred to as “doping” and banned by all major sports.
Hypothesis
If an earthworm is given anabolic steroids, its growth rate will significantly increase compared to
an earthworm not given steroids.
Experimental Procedure
Independent Variable: Treatment with/without anabolic steroid
Dependent Variable: Earthworm growth (in grams)
Constants: Species of earthworm, starting age of earthworm, soil condition, moisture level, soil
temperature
Control group: 10 earthworms that do not receive any anabolic steroids
Experimental group 1: 5 earthworms treated with 5cc’s anabolic steroid
Experimental group 2: 5 earthworms treated with 10 ccs of anabolic steroids
2
Materials Needed







15 individual specimens of Lumbricus terestrius (the common earthworm)
15 containers
soil
water
anabolic steroid
hypodermic needle w/ 1cc increments
digital scale
Procedure
1. Obtain 15 earthworms of the same age and place them in a container of worm habitat soil
2. Measure each worm’s mass and record as “initial mass”
3. Beginning on day 2 at 7 AM, inject each of the 5 worms in experimental group 1 with 5
ccs of anabolic steroids, and each of experimental group 2 with 10 ccs of steroid.
4. At 4 PM measure the mass of each worm in grams and record.
5. Add 5 ml of H2O to each of the 15 containers, evenly distributed
6. Repeat steps 3-5 each day for 25 days
Data
See Table A on page 3
Analysis
Effect of Steroids on Worm Growth
14
12
Mass of worm
10
8
Control Group
5 cc Anabolic Steroids
10 cc Anabolic Steroids
6
4
2
0
1
3
5
7
9
11
13
Days
3
15
17
19
21
23
25
Table A
Day 25
Day 24
Day 23
Day 22
Day 21
Day 20
Day 19
Day 18
Day 17
Day 16
Day 15
Day 14
Day 13
Day 12
Day 11
Day 10
Day 9
Day 8
Day 7
Day 6
Day 5
Day 4
Day 3
Day 2
Initial
Control Group
Worm 1
2.2
2.4
2.4
2.5
2.5
2.6
2.6
2.7
2.7
2.8
2.9
3
3
3.1
3.1
3.2
3.2
3.3
3.4
3.4
3.5
3.6
3.6
3.7
3.8
Worm 2
Worm 3
2.1
2
2.1
2
2.1
2.3
2.3
2.3
2.3
2.3
2.4
2.3
2.5
2.4
2.6
2.4
2.6
2.6
2.6
2.5
2.7
2.6
2.8
2.6
2.9
2.7
2.9
2.7
2.9
2.8
2.9
2.8
3
2.9
3
2.9
3
3
3.1
3
3.2
3
3.3
3.1
3.3
3.1
3.3
3.2
3.3
3.2
Worm 4
Worm 5
2.4
2.2
2.4
2.2
2.4
2.3
2.5
2.3
2.5
2.3
2.6
2.4
2.6
2.5
2.7
2.6
2.7
2.6
2.8
2.6
2.9
2.7
3
2.8
3
2.9
3.1
2.9
3.1
2.9
3.2
2.9
3.2
3
3.3
3
3.4
3
3.4
3.1
3.5
3.2
3.6
3.3
3.6
3.3
3.7
3.3
3.8
3.3
Average
2.2
2.2
2.3
2.4
2.4
2.5
2.5
2.6
2.6
2.7
2.8
2.8
2.9
2.9
3
3
3.1
3.1
3.2
3.2
3.3
3.4
3.4
3.4
3.5
Worm 6
Worm 7
2.2
2.5
2.4
2.5
2.6
2.6
2.8
2.7
3
2.8
3.2
3
3.4
3.1
3.6
3.2
3.8
3.3
4
3.4
4.2
3.5
4.4
3.7
4.6
3.8
4.8
3.9
5
4
5.2
4.1
5.4
4.2
5.6
4.4
5.8
4.5
6
4.6
6.2
4.7
6.4
4.8
6.6
4.9
6.8
5.1
7
5.2
Worm 8
Worm 9
2.3
2.2
2.3
2.4
2.4
2.6
2.4
2.8
2.6
3
2.6
3.2
2.8
3.4
2.8
3.6
2.9
3.8
3
4
3.1
4.2
3.2
4.4
3.3
4.6
3.4
4.8
3.5
5
3.5
5.2
3.6
5.4
3.7
5.6
3.8
5.8
3.9
6
4
6.2
4.1
6.4
4.2
6.6
4.3
6.8
4.3
7
Worm 10
2.1
2.5
2.6
2.7
2.8
3
3.1
3.2
3.3
3.4
3.5
3.7
3.8
3.9
4
4.1
4.2
4.4
4.5
4.6
4.7
4.8
4.9
5.1
5.2
Average
2.3
2.4
2.6
2.7
2.8
3
3.2
3.3
3.4
3.6
3.7
3.9
4
4.1
4.3
4.4
4.6
4.7
4.9
5
5.2
5.3
5.4
5.6
5.7
Experiment
Group 2
Worm 11
2.1
2.4
2.7
3
3.3
3.6
3.9
4.2
4.5
4.8
5.1
5.4
5.7
6
6.3
6.6
6.9
7.2
7.5
7.8
8.1
8.4
8.7
9
9.3
Worm 12
Worm 13
2.4
2.1
2.7
2.4
3
2.7
3.2
3.4
3.5
3.6
3.7
4.1
3.9
4.8
4.1
5.3
4.4
5.7
4.6
6.2
4.8
6.7
5.1
7.2
5.3
7.6
5.5
8.1
5.8
8.6
6
9.1
6.2
9.6
6.5
10
6.7
11
6.9
11
7.2
12
7.4
12
7.6
13
7.9
13
8.1
13
Worm 14
Worm 15
2.3
2.1
3.1
2.5
3.6
3.2
3.9
3.7
4.3
4.2
4.7
4.8
5.1
5.3
5.5
5.8
5.9
6.4
6.3
6.9
6.7
7.5
7.1
8
7.5
8.5
7.9
9.1
8.3
9.6
8.7
10
9.1
11
9.5
11
9.9
12
10
12
11
13
11
13
12
14
12
14
12
15
Average
2.2
2.6
3
3.4
3.8
4.2
4.6
5
5.4
5.8
6.2
6.6
6.9
7.3
7.7
8.1
8.5
8.9
9.3
9.7
10
10
11
11
12
Experiment
Group 1
4
Conclusion
As can be clearly demonstrated by the data analysis, the earthworms that received the
anabolic steroids grew faster than the control group. The group receiving 10cc per day grew at a
borderline alarming rate. In a little less than a month, the worms had increased their mass by
nearly six times. The average increase was from 2.2g to 12g. Our hypothesis has been
thoroughly supported by this experiment.
Sources of error
Human error is always a source of error in any experiment. Possible mistakes in reading
the scale, improper measuring of steroid, etc. could have occurred. Also only using one
hypodermic needle for all the worms could possibly contaminate the other worms. As with most
experiments, the results would have been more conclusive had the experiment been conducted
for a longer period of time, and with more worm subjects.
Bibliography
Hershberger, J.G., Shipley, E.G., Meyer, R.K. (1953). Myotropic activity of
19-nortestosterone and other steroids determined by modified
levator ani muscle method. Proc Soc Exp Biol Med, 83, 175-180.
Living Invertebrates, Editors Pearse and Buchsbaum, 1986, Boxwood
Press, Pacific Grove, Ca.
Acknowledgements
So many people to thank for making this possible. Firstly, we would like to say thank
you to the wonderful administration at this school. They have made it possible to conduct these
experiments on school grounds. Now, some of the worms have escaped and are on the run. Not
to worry, however, if you see them, please just let us know and we will come and take them
down with a tazer. Do not, repeat, do not attempt to capture them yourself.
Family, wow! All the support and encouragement from our families really made this
happen. There were times when quitting was a real option and our families really pushed us to
keep at it.
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