P1 - Investigate The Effects Of Caffeine On Heart Rate In Daphnia

Question 1

Why Are Daphnia Suitable For Investigating Heart Rate?
(2 Points)

Answer 1

~ Have transparent bodies.

~ Internal organs can be observed using a light microscope.

Question 2

What Apparatus Is Used In The Daphnia Experiment?
(7 Points)

Answer 2

~ Light microscope.

~ Cavity slide.

~ Culture of daphnia.

~ Pipette.

~ Caffeine solutions at a range of concentrations.

~ Distilled water.

~ Stop watch.

Question 3

Describe The Method Of Investigating The Effect Of Caffeine On The Heart Rate Daphnia
(7 Points)

Answer 3

1) Prepare 5 different concentrations of caffeine solution and a control solution of distilled water.

2) Transfer one daphnia onto the cavity slide, using a pipette.

3) Using a pipette, place a few drops of caffeine solutions onto the daphnia.

4) Place the cavity slide onto the stage of the microscope and observe the daphnia under low power.

5) Use a stopwatch to time 20 seconds and count the number of heart beats, by making dots on paper.

6) Count the dots and express the heart rate as BPM, by x3.

7) Repeat 10 times with other concentrations of caffeine and other daphnia.

Question 4

Describe The Ethical Considerations Of This Experiment
(2 Points)

Answer 4

~ They cannot give consent or express pain.

~ More acceptable to use invertebrates than vertebrates as they have a less sophisticated nervous system.