The Effects of Depressants on a Lumbriculus Variegates Pulse Rate
By: Jared Fearby and Sarah Kuehne,
Albion High School
Genesee Community College Bio 100
Introduction: The Lumbriculus Variegates or
commonly known as the blackworm is a type of
Phylum Annelid with a two cell layers, tissues and
organs. the skin is transparent, this makes it good
for studying its pulse rates due to being able to
easily see its circulatory system. The blackworm
can be found at the edges of ponds, lakes or
marshes. In Captivity they reproduce asexually by
dividing into two separate pieces and regenerating
their head and or tail.
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Materials
A microscope
2 blackworms
A slide
Plain water
Water with depressant
Timer
Hypothesis: The blackworms in the plain
water will have a higher pulse rate then
normal worms in the depressant.
Independent variable: The plain water.
Dependent variable: The pulse rate of the
worms.
Procedure: 1) Select blackworm from plain water dish and put on wells
slide. 2) Take the blackworms pulse rate for a minute using a microscope.
3) Repeat this nine more times and record data into notebook. 4) Take
blackworm off the wells slide and and put back into its plain water dish. 5)
Select a blackworm from the dish that contains a depressant in the water
and put on wells slide. 6) Record its pulse rate ten times using the
microscope. 7) Put blackworm back in the dish that contains the water with
the depressant and clean up.
Control setups: The blackworms in the
depressant.
Constants: the temperature of the water
the worms are in.
Count #
Pulse Rate
(Plain water)
Pulse Rate
(Water
w//Depressant)
1
13
12
2
12
14
3
11
19
4
16
20
5
19
18
6
19
17
7
18
15
8
27
17
9
20
15
10
18
15
Drewes, C., (2004, september) Lumbriculus variegatus: A Biology Profile, Pbworks.com
Drewes, Charles D., Dr. “Lumbriculus variegatus: a Biology Profile.”invertabrate neurobiology (n.d.):
Results: the data showed that the pulse rate of the
blackworms immersed in the plain water was slightly
higher then worms immersed in the depressant.
Conclusion: These results help support our hypothesis
that worms in plain water will have a higher pulse rate
then blackworms in a depressant. Some limitations of this
experiment is that we couldn't control how much they
move. Another limitation of the experiment is that we
couldn't control the dosage of depressant the worms
were given. The last limitation of the experiment is that
we couldn't control how long they were in the water
containing the depressant. An unexpected result from
doing the tests is that the depressant didn't slow down
the pulse rate as much as we thought it would. Some
changes that occured that could have affected the
outcome of the experiment is that we used multiple
different worms, This could have affected the data
because some worms may have a faster or slower pulse
rate. A future avenue of research could be to test the
pulse rate of the worm in plain water, then to add the
depressant to that worm.