Student Name
BIOL 3030
Section Number
T.A Name
Professor Name
An Observation of the Adaptive Measures of Daphnia Magna to The Introduction of Chemicals and Temperature Variations of Its Habitat
Date of Lab
Date of Report Submission
Introduction
Every organism has a unique ecosystem, its natural habitat, in which it lives, and where its basic needs such as food, water, and shelter necessary for organism survival are met. An organism’s habitat allows for it to survive and be able to reproduce under specific ecological conditions. However, conditions do not always hold in the natural environment as the environment is ever-changing and sometimes unpredictable, thus the need for an organism to adapt. For organisms to survive in any habitat, they need to adapt to their environment, i.e., adapt to the ecosystem’s climatic conditions, competitors to water, food and shelter, and predators. Adaptation is the modification or change in the organism’s body or behavior, enabling it to survive in its natural environment (LeGuen, n.d.) and avoid extinction. This change may be physical or a structural adaptation, a change in how certain body functions work, e.g., circulation and respiration, or a change in general organism behavior.
Daphnia Magna is a relatively small freshwater zooplankton found in freshwater bodies and is most commonly referred to as water fleas as they swim in spasmodic motions. They are very susceptible to modifications to their environment; for example, when there is low oxygen levels in the water, D. Magna increases hemoglobin production, which causes them to turn red. Furthermore, during weather conditions that are harsh for D. Magna, they can produce resting eggs, resist time, heat, cold, and drought (Deken, 2005). This experiment was used to monitor adaptive measures that D. Magna takes when temperature variations of its habitat and when various chemicals are introduced to its habitat. The water fleas are subjected to a temperature range of between 100 C and 350 C in the lab experiment to determine how they react to variation in temperature in their habitat. They are further subjected to the chemicals Acetylcholine, Atropine, and Rotenone. The heart rate is observed by measuring the beats per minute (BPM) of the D. Magna. Ventilation rates are taken by observing the number of movements of the phyllopodia. These measurements are then recorded.
The temperature has an acute effect on organisms’ bodily processes, functioning, structure, and biochemistry through essential physical and chemical limitations (Yampolsky, Schaer, & Ebert, 2014). Most species have temperature ranges where they perform best and where exposure outside those ranges has a cost. To observe how D. Magna are affected by temperature, the water flea’s heartbeat and ventilation rate is observed at room temperature (250 C), which is the control, and then the temperature is adjusted by adding ice water for the units lower than room temperature and warm water for those greater than 250 C.
According to Zongming et al. (2008), an organism’s behavior is affected by exposure to toxic chemicals. However, the behavioral response of an organism to chemicals was affected by exposure concentration rather than the chemical’s toxic characteristics. In essence, this means that toxic chemicals have different toxic characteristics, but less is known about an organism’s behavioral responses to stresses of toxic chemicals with different toxic characteristics (Zongming, Zhiliang, Mei, Zijian, & Rongshu, 2008). To observe how the water flea is affected by chemicals, a water flea’s heart rate and ventilation rate are taken before introducing the chemicals and then after the chemical is introduced. A different water flea is used to observe each chemical’s effect, and the experiment is replicated till the D. Magna has been exposed to all the chemicals to be tested.
Results
From the experiment on D. Magna, the following findings were observed:
Graph1: How temperature affected the heart rate and ventilation rates of D. Magna
The results represented in Table 1 (found in appendix I) and the graph above show the influence of temperature on the heart rate and ventilation rate of the D. Magna. At room temperature (25°C / [ K^-1 = 0.003354016]) the heart rate and ventilation rate are at 202 and 124 respectively. The more the temperature decreases, the more the heart rate and ventilation rates decrease. An increase in temperature causes a corresponding increase in both the heart rate and ventilation rate. The water flea’s conduct in terms of heartbeat rate and ventilation rate to temperature change implies a linear relationship between the three data sets.
Graph 2: An illustration of the effect on D. Magna Hr & Vr from adding Acetylcholine and Atropine to its habitat
Graph 3: An illustration of the effect on D. Magna Hr & Vr from adding Rotenone to its habitat
There is also a noticeable increase in the heart rate and Ventilation rate of the D. Magna as the chemicals Acetylcholine, Atropine, and Rotenone are introduced into the habitat, as can be observed in Graph 2 and Graph 3 above.
| Temperature Range | Category | Heart rate | Ventilation |
| 283.15K-293.15K
(10°C -20°C) |
Q10 | 1.4375 | 1.000 |
| Rate of Change (BPM/K) | 0.2260 | 0.1554 | |
| 293.15K-303.15K
(20°C -30°C) |
Q10 | 2.4130 | 3.500 |
| Rate of Change (BPM/K) | 0.7323 | 0.5080 |
Table 1: Q10 Levels for Ventilation Rates and Heart Rates
The Q10 levels were consistent with the formula, which implies smaller amounts for smaller changes in temperature, and more massive amounts of change for more considerable temperature differences, as is observed in all exponential functions.
Discussion
As observed, the D. Magna was able to acclimate to temperature changes in their habitat where the increase in temperatures above their habitat temperature ( 25°C) caused an increase in their metabolic activity as seen with the increase in heartbeat and ventilation rates. This was because the sample water fleas had never been exposed to such conditions before and were in the process of adapting to the variations in temperature. According to Yampolsky et al., long-term exposure to high temperature would cause sustained metabolic hyperactivity, which may demand increased glucose and stored fat utilization, for which depletion and lack of replacement would cause a decrease in body weight the D. Magna. Additionally, hyperosmotic stress resulting from a depletion of water present (also due to long-term high metabolic activity) in the D. Magna could reduce the freshwater flea’s size and mass (Yampolsky, Schaer, & Ebert, 2014). On the other hand, a decrease in temperature below their habitat temperature ( 25°C) causes the metabolic rate to decrease. This high tolerance to variable changes in temperature shows the water flea’s thermal acclimatization and local adaptation ability.
In the short term, the introduction of the drugs into the water fleas’ local environment caused a substantial increase in the organism’s heartbeat rate and ventilation rates as it tried to adapt to the changes in its environment. One can observe that the heart rate has a more substantial increase than the ventilation rate with all three drugs. According to Damasio et al., 2007 the adaptation of the water flea in the case where chemicals are introduced into its habitat is due to the water flea having genetic information that made it aware of the presence of the chemicals being introduced into its habitat, which allowed it to adapt.
Conclusion
One of the primary aspects of living organisms is their ability to respond to changes in their environment. In this lab, one can observe how D. Magna adapts to changes in temperature and chemical composition of its environment by measuring its heartbeat and ventilation rate. The range of temperatures used are between 10-35, and three different chemicals are also used in this experiment. The recorded results show that D. Magna is highly sensitive and aware of changes in its environment and responds relatively quickly to adapt to changes in its environment.
References
Damasio, J., Guilhermino, L., Soares, A. M., Riva, M. C., & Barata, C. (2007). Biochemical mechanisms of resistance in Daphnia Magna exposed to the insecticide fenitrothion. Chemosphere, 74-82.
Deken, A. (2005). Background information on Daphnia. In A. Deken, SEEING RED: Daphnia and Hemoglobin: A MIDDLE SCHOOL CURRICULUM UNIT MODELING ECOLOGICAL INTERACTIONS AND THE SIGNIFICANCE OF ADAPTATIONS (pp. 6-8). Missouri: Howard Hughes Medical Institute, Washington University Science Outreach.
LeGuen, R. (n.d.). Habitat and Adaptation. Retrieved from World Wide Fund For Nature: https://wwf.panda.org/discover/knowledge_hub/teacher_resources/webfieldtrips/hab_adaptation/
Yampolsky, L. Y., Schaer, M. T., & Ebert, D. (2014). Adaptive phenotypic plasticity and local adaptation for temperature tolerance in freshwater zooplankton. Proceeding of the Royal Society Biological Sciences. doi:https://doi.org/10.1098/rspb.2013.2744
Yampolsky, L. Y., Schaer, T. M., & Ebert, D. (2014). Adaptive phenotypic plasticity and local adaptation for temperature tolerance in freshwater zooplankton. The Royal Society Publishing. doi:10.1098/RSPB.2013.2744
Zongming, R., Zhiliang, L., Mei, M., Zijian, W., & Rongshu, F. (2008). Behavioral Responses of Daphnia Magna to Stresses of Chemicals with Different Toxic Characteristics. Bulletin of Environmental Contamination and Toxicology, 82(310), 82-100. Retrieved from https://link.springer.com/article/10.1007/s00128-008-9588-1
Appendix I: How temperature affected the heart rate and ventilation rates
Formulas:
1). To convert degree Celsius (°C) to Kelvin (K)
Where x is the value of temperature in °C
x°C + 273.15 = 274.15K
2). To find the inverse of temperature (K^-1)
Where T represents temperature in Kelvin
= 1/T
| Temperature (T) Celsius | Heart Rate (Hr) | Ventilation Rate (Vr) | Temperature (K) | Log (Hr) | Log (Vr) | 1/T |
| 10 | 64 | 44 | 283.15 | 1.806179974 | 1.643452676 | 0.003531697 |
| 15 | 104 | 50 | 288.15 | 2.017033339 | 1.698970004 | 0.003470415 |
| 20 | 92 | 44 | 293.15 | 1.963787827 | 1.643452676 | 0.003411223 |
| 25 | 202 | 124 | 298.15 | 2.305351369 | 2.093421685 | 0.003354016 |
| 30 | 222 | 154 | 303.15 | 2.346352974 | 2.187520721 | 0.003298697 |
| 35 | 292 | 234 | 308.15 | 2.465382851 | 2.369215857 | 0.003245173 |
Appendix II: How Chemicals affected heart rate and ventilation rates.
| Baseline
(Before Acetylcholine) |
Acetylcholine | Baseline
(Before Atropine) |
Atropine | Baseline (Before Rotenone) | Rotenone | |
| Heart Rate (Hr) | 234 | 286 | 244 | 258 | 258 | 310 |
| Ventilation Rate (Vr) | 214 | 228 | 182 | 168 | 238 | 250 |
Appendix III: Q10 Levels for Ventilation Rates and Heart Rates
Q10 = (K2/K1) 10/T2-T1
where K2 and K1 are the rates of either heartbeat or ventilation rates at temperatures T1 and T2
| Temperature Range | Category | Heart rate | Ventilation |
| 283.15K-293.15K
(10°C -20°C) |
Q10 | 1.4375 | 1.000 |
| Rate of Change (BPM/K) | 0.2260 | 0.1554 | |
| 293.15K-303.15K
(20°C -30°C) |
Q10 | 2.4130 | 3.500 |
| Rate of Change (BPM/K) | 0.7323 | 0.5080 |
Sample calculation of
Q10 of 283.15K-293.15K (10°C -20°C)
Heartrate =
(92/64) =1.4375
10/ (293.15-283.15) =1
1.4375^1=1.4375
Ventilation =
(44/44) =1
10/ (293.15-283.15) =1
11^1=1.000