What is the heartbeat of a Daphnia?
Results. Seventy-two Daphnia were used in the initial experiments. The average initial heart rate was 354 beats minute——1 (range: 91——521 beats minute——1). The large variation in heart rate between animals cannot be attributed to variation in their size.
Where is the heart of a Daphnia?
Daphnia have an open blood circulation. The heart is located dorsally and anterior from the brood chamber. At 20ºC, it beats about 200 times per minute, slowing down at lower temperatures.
Do Daphnia have a nervous system?
Daphnia magna have an autonomic nervous system (ANS) similar to the ANS of mammals. Although they have a similar ANS, Daphnia do have many anatomical differences from mammals such as a ventral nerve cord, a 3- section brain, and neuronal cells located in their antenna (Tollrian et al., 2012).
Does nicotine affect Daphnia heart rate?
The 25% nicotine solution caused the heart rate to decrease at a steady pace for one minute and then drastically decrease. Multiple trials found that nicotine causes a decrease in heart rate for Daphnia magna, with higher concentrations of nicotine having a stronger effect.
Do Daphnia have a parasympathetic nervous system?
Do Daphnia have veins?
Although Daphnia has no blood vessels, blood is circulated throughout the body cavity by a heart that may pulse 300 times a minute. Flowing within Daphnia’s transparent carapace, the blood reaches every body part, then returns and circulates again.
What does nicotine do to Daphnia?
How does nicotine affect heart rate?
Nicotine is a dangerous and highly addictive chemical. It can cause an increase in blood pressure, heart rate, flow of blood to the heart and a narrowing of the arteries (vessels that carry blood). Nicotine may also contribute to the hardening of the arterial walls, which in turn, may lead to a heart attack.
How to make the most of the Daphnia heart rate lab?
Students commonly test the effects of chemical agents on the heart rate of the crustacean Daphnia magna, but the procedure has never been optimized. We determined the effects of three concentrations of ethanol, nicotine, and caffeine and of a control solution on heart rate in Daphnia.
How does caffeine affect heart rate in Daphnia?
Here, we report on the effects of ethanol, nicotine, and caffeine on heart rate in Daphnia. Each compound was tested at three concentrations. We determined their effects, the time necessary to achieve those effects, and whether or not the effects could be reversed.
Why are Daphnia so easy to care for?
Heart rates recover quickly after removing 5%% ethanol, which allows students to explore reversibility as an alternative to having a separate control group. Daphnia are small crustaceans that are inexpensive, easy to care for, and transparent. The latter property allows students to easily observe the beating heart ( Figure 1 ).
How is the metabolic rate of Daphnia affected?
Daphnia is poikilothermic, which means that its body temperature and therefore its metabolic rate are affected directly by the temperature of the environment. The change in metabolic rate is reflected in the rate at which the heart beats (cardiac frequency).