Essay On Daphnia

Title: Physiological Changes in the Heart Rate of Daphnia magna When Exposed to Stimulants (Caffeine and Alcohol).

The purpose of the experiment was to investigate the physiological effects of epinephrine on the heart rate of the organism called Daphnia magna as well as to calculate the median effective dose. Daphnia magna are arthropods found in pools of freshwater or areas where freshwater meets seawater in Western Europe and the Atlantic Coastline of the United States (Elenbaas, 2013). They are about two to five millimeters in length and have a transparent shell. Their heart is located on the dorsal side of the organism and the gills are on the ventral side. Daphnia magna also has two antennae and six appendages that are used to bring food and oxygen to the organism’s gills and produce movements.

Phytoplankton are microscopic photosynthesising organisms which live in water. In favourable environmental conditions they have a very high rate of reproduction. They are eaten by microscopic animals called zooplankton. In an investigation, samples of water were removed from a lake at intervals over a twelve-month period and the biomasses of these organisms were determined. The results are shown in the graph.

effected the heartbeat rate of a Daphnia. The results of the experiment were that the

Daphnia, also known as water fleas, are small crustaceans about 1mm-5mm long and are part of the freshwater zooplankton (Ebert 2005, Hutchinson 2005 & Clifford 1991). Daphnia can be found in most fresh water habitats such as freshwater springs, ponds and reservoirs and are the predominant food for planktivorous fish. Dapnia are ‘filter feeders’ meaning they feed on small particles suspended in the water which can include algae. It has been found that daphnia tend to migrate to the upper parts of the water at night and return to the lower parts of the water in the day to hide from predators (Ebert 2005) (Hutchinson 2005). Daphnia can reproduce through sexual reproduction and also asexual

In this research paper I will talk about how a large decrease in the algae population in the Chesapeake Bay will cause problems for not just fish and other species but the people who fish and make a living off of it. A large decrease in algae population will have a domino effect on the food chain. Having a major decrease in algae will hurt how others species live and protect themselves.

To conduct this study a culture of living Daphnia were collected from a nearby natural water source area.

Daphnia is an order of cladoceran that are a part of the genus of small crustaceans ranging from one to five millimeters in length (Campbell, 2004; Corroto 2010). Daphnia are also naturally transparent, allowing for a variety of research opportunities that are observable with current day technology. Water fleas are another name for Daphnia due to their distinct, jerky swimming patterns (Chin, 2011; Campbell, 2004). Additionally, Daphnia seem to have tufts of hair, relatively large eyes, and red “lips”. Daphnia also feature an ocellus, a light-sensing organ under the compound eye (Chin, 2011; Corotto, 2010).

Investigating the Effect of Alcohol on Heartbeat of Daphnia Daphnia are the organisms that are involved in this experiment to find out what effect alcohol has on their heartbeat. It is easy to study the effects of alcohol on the heart of Daphnia as the organ can be easily seen through the transparent body of Daphnia. The number of heartbeats may be counted before submersion in alcohol and after submersion in alcohol to investigate the effect of alcohol. Daphnia belong to the Phylum Arthropoda and are Branchiopoda which belong to the class, Crustacea. Daphnia are invertebrates and also have an exoskeleton, jointed appendages, a dorsal heart and open blood system.

The experiment took place in a laboratory setting, and the first step was obtaining sixty individual Daphnia magna (that were neither adults nor tiny offspring) from a large tank in the lab. These individuals were equally divided into three groups; low density, medium density, and high density. The twenty Daphnia assigned to the low density group were split into four groups of five and pipetted into one of four tubes filled with 10mL of Chlamydomonas algae. The twenty Daphnia assigned to the medium density group were split into two groups of ten and placed into one of two tubes also filled up to 10mL with Chlamydomonas. The final twenty Daphnia were all placed into a single tube filled with 10mL of the algae. In order to avoid suffocation-related

The purpose of this experiment is to understand the effects of nutrient enrichment and eutrophication, using samples of water from Rio Salado and Encanto Park. The samples will contain different concentration levels of nitrogen, phosphorous and nitrogen and phosphorous combined and the impact it has on algae growth. The results recorded showed that the nitrogen concentration levels had a little change, phosphorous levels had a higher change and phosphorous and nitrogen combined had a significantly higher change, resulting in higher algae growth. The results showed that phosphorous indeed is a limiting nutrient in algae growth, but to achieve the highest growth rate, both nitrogen and phosphorous need to be combined.

Daphnia are used to test water toxicity, they are a vital part of fresh water ecosystems. They are a food source for smaller fish and invertebrates and considered to be a consumer of algae and bacteria (Elbert, 2005). These small crustaceans range in size from 2-5mm long and are commonly referred to as water fleas. Daphnia belong to the group called Daphniidae, which is a relative of freshwater shrimp. It is easy to see the internal organs of daphnia because of a transparent taco shell like carapace. A carapace is the hard outer part of a shell or covering. A daphnia’s life span can range between 1-56 days. (Elenbaas, 2013; Clare 2002). The comfortable pH level for daphnia is between 7.2 and 8.5 (Clare, 2002).

Predators and prey are organisms that interrelate, and they can influence on another’s success in reproduction. Predators are organisms that consume other organisms-their prey. These two organisms evolve together. They live in an environment where they must develop certain adaptations to survive. When an adaptation is developed, it gives an organism certain physical characteristics that create an advantage for survival and can come to dominate in a population. An adaptation aids survival by either decreasing a prey's chance of being eaten, or by increasing a predator's chance of obtaining food to survive and reproduce. Predators must fight for food. They face density-independent

Doryphoros by Polykleitos was originally a Greek bronze made around 450-40B.C. The only way we can see it today is through the Roman marble copies (which is common of many Greek statues.) Some supports had to be added for the change in material, resulting in the addition of the form resembling a tree trunk, the support on the left foot, and the small bar bridging the gap between his right wrist and hip. Doryphoros was originally holding a spear in his left hand; appropriate, given that his name means, literally, “spear-bearer.” The sculpture is a well-known and early example of classical Greek contrapposto (the shifting of weight onto one leg and off-axis shoulders and arms.) One leg nearly appears to be lifting off the ground, giving the

The urea cycle plays an important role in diatom metabolism, serving as a distribution and recycling center for inorganic carbon and nitrogen. This cycle is an essential biological process in diatoms, contributing to diatom’s nutrients in order to compensate for the lack of important macronutrients that could increase their growth level within increasing the metabolism process (Allen,