Learn: Core Practical 1 - Investigating the Effect of Caffeine on Daphnia Heart Rate

Welcome!You've already learned about the cardiovascular system and how the heart pumps blood around the body. Today, we'll build on that by exploring how caffeine affects the heart rate of Daphnia, a small freshwater organism.

What is Caffeine?Caffeine is a stimulant often found in coffee, tea, and energy drinks. It affects the nervous system and heart rate by blocking adenosine receptors, leading to increased alertness and energy.

Why Use Daphnia?Daphnia are small aquatic crustaceans with transparent bodies, making it easy to observe their heart rate under a microscope. They are often used in experiments because they respond quickly to environmental changes.

Setting Up the ExperimentTo investigate caffeine's effect on Daphnia heart rate, we need to follow ethical guidelines and ensure the well-being of the organisms. Daphnia should not be exposed to extreme conditions or harm during the experiment.

Experimental MethodHere's how to conduct the experiment:Place Daphnia in a drop of water on a microscope slide.Add a measured concentration of caffeine solution to the water.Observe and record their heart rate under the microscope by counting beats per minute.

Ethical ConsiderationsUsing living organisms requires ethical care. Minimise stress to Daphnia, avoid extreme caffeine concentrations, and return them to their natural habitat after the experiment.

Review Time!Great work! You've learned about caffeine, Daphnia, and the experimental method. Let's test your understanding with a few final questions.

Well Done!You've successfully completed the lesson on investigating the effect of caffeine on Daphnia heart rate. Keep exploring how substances affect biological systems!