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Effect of time spent in vodka on black worm pulse rate

Purpose: If blackworms are soaked in vodka for 10 minute intervals for 50 minutes then their pulse rate will steadily increase.

MATERIALS:Capillary tubes (75mm)Shallow pan (27cm X 22cm)StereoscopeCork Stoppers1mL PipetteStop watchVodka Solution (.1mM)

1. LAB PROCEDURE:

(*Fore note: This procedure is most possible with multiple persons measuring the pulse rate of

the worms.)

1. Choose at least 60 blackworms (it is highly recommended that you choose more) at random

from a stock container.

2. Obtain a baseline pulse rate of the Lumbrisculus worm by recording its pulse rate with the

following procedure. Take up an individual worm into the pipette and gently squeeze it into a

capillary tube. Then balance the tube on top of two cork stoppers under the stereoscope at x40

magnification and count its pulse for 1 minute. Repeat 9 more times to complete the trial. Record

in a data table.

3. Fill a shallow pan with 40% vodka (.1mM) solution and quickly transfer at least 60 worms

into it at approximately the same time. Note the time/begin timing.

4. Wait 10 minutes from the initial time and quickly record the pulse rate of 10 ideal specimens

from the vodka solution. Do this by taking up an individual worm into the pipette and gently

squeezing it into a capillary tube. Then balance the tube on top of two cork stoppers under the

stereoscope at x40 magnification and count the pulse for 1 minute. Record in a data table.

5. Repeat step 4 for 10 minute intervals up to 50 minutes.

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6. Collect data

Research: Lumbriculus variegates is the scientific name for the black worm. The

worm is indigenous to shallow, muddy water areas in the United States. When areas such as

these become contaminated by chemicals the black worm can be a useful biological detector of

this.

Black worms have similar nervous and endocrine systems to humans. Oxygenated blood

is pumped from the posterior of the worm to the anterior at a constant rate. When drugs are

diffused in worms their pulsation rate is affected, similar to humans. The worms, then, can be

observed to determine the effect of drugs on pulsation rate.

Alcohol is a vasodilator; it dilates the blood vessels causing an increase in blood flow.

The blood flow is forced to cover a larger body volume. The heart rate then increases to send

sufficient blood throughout the body. Due to the similarities in human and black worm nervous

systems black worm pulse rate in conjunction with alcohol should produce similar results;

increased pulse rate.

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Data Table:

Interval

of Time

(minutes)

±1

minute

Pulse

(Beats

per

minute)

± 1

beat

Averag

e (beats

per

minute)

± 1

beat

Trials for

each

interval

1 2 3 4 5 6 7 8 9 10

Control

(no

vodka)

15 16 15 15 15 16 17 19 15 15 16

10 29 30 24 33 19 36 31 23 40 30 29

20 35 32 34 36 22 30 37 44 29 48 35

30 46 44 44 38 29 30 30 27 32 52 37

40 57 52 66 48 36 27 44 55 59 66 51

50 62 49 55 50 48 46 52 47 52 59 52

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Line Graph:

0 5 10 15 20 25 30 35 40 45 50 55 600

10

20

30

40

50

60

f(x) = 1.33428981348637 x − 23.9239598278336R² = 0.945439639270342

Pulse rate of black worms per 10 minute intervals

Series2Linear (Series2)

Average pulse rate per minute

10 m

inut

e in

terv

als

Standard deviation: Control- 4.0, 10 minutes- 5.4, 20 minutes- 5.9, 30

minutes-6.1, 40 minutes- 7.1, 50 minutes- 7.2

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Conclusion: The data collected from the 60 worms supports the hypothesis and research. Due

to in increase in time spent in the vodka the worms had an increased pulse rate per minute. The

graph depicts this steady increase from 0 minutes spent in vodka to 50 minutes. The averages of

the 10 worms at each interval clearly show this increase, refer to the data table.

When working with live test subjects it is important to the know that the actual organism

is an uncontrollable variable. The worms could easily move in the capillary tubes which affected

the count of the pulse rate. Each interval included outliers that skewed the averages to be higher

or lower than accurate. The stress of being handled could be an uncontrollable variable upon the

experiment as well. Random error due to human counting also skewed the results. The worms

pulse rate is quicker at the posterior end. This means the pulse rate fluctuates depending on

where it is being recorded from the worm.

There are several steps you can take to decrease errors. To reduce outliers conduct more

trials to make a more accurate average. To reduce the error caused by the fluctuation of the

worms heart rate in relation to where it is being recorded on the worm one should chose a single

segment of the worm and record the pulse rate of each worm at that same segment.