Effect of Environmental Conditions on Heart Rate:

Experimenting with DaphniaAP Biology Lab 10

http://cfb.unh.edu/cfbkey/html/anatomy.html

http://ebiomedia.com/gall/classics/Daphnia/daphnia_behave2.html

Daphnia Heart Rate

Procedure

• Obtain 2 concave depression slide

• Add a Daphnia to one of the slides

• Top with inverted second slide and secure with rubber bands OR cover slip

Heart Rate and Temperature

• Use culture dishes to set up baths of varying temperatures

• Start with the coolest bath• Count number of heart beats in 10 seconds

Effect of Temperature on Metabolism

• Ectothermic animals– Rate of metabolism dependent on

temperature– Metabolic rate and activity increases

dramatically between 5 and 35C

“Q10”

• Increase in Metabolism expressed in terms of “Q10”

– Rate of metabolic rate at one temperature compared to the metabolic rate at a temperature 10C lower

“Q10”

• Q10 = rate at higher temp. rate at lower temp.

Q10 = [k2/k1]

k1 = heart rate at lower temp.

k2 = heart rate at higher temp.

Drug Effects on Heart Rate

• Nicotine—stimulant– Increases heart rate and blood pressure

• Alcohol—depressant– At first lowers blood pressure, but then

rebounds to increase blood pressure

• Caffeine—stimulant– Increases heart rate and blood pressure

• Aspirin– Decrease heart rate and blood pressure