Daphnia Hypothesis

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

The materials used to preform the lab include; living Daphnia, water, 3 pieces of thread, slide and cover slides, microscope, alcohol substance. The pieces of thread will be used to keep the Daphnia in place on the slide under the microscope. Placing the Daphnia under the microscope we were able to see the heart located on the upper part of the Daphnia. With the transparent structure of the Daphnia. We are able to visually see the solution affecting the heart beats. Before applying the solution we took the three readings of the normal Daphnia heart rate for 15 seconds and multiply the number by 4 to collect the number of 1 minute. After we applied the same method observing the heart beat affected by the solution and recorded the heart beats

Background: Daphnia is also known as diploid or water fleas belong to a group of animals named crustaceans. They are too small to be seen with the naked eye. There are two chromosomes are from the father and mother also, they are multicellular. They live in freshwater and in a few terrestrial habitats. (Textbook 595 & 680)

When a Hydra tentacle touched Daphnia, the Daphnia appeared to get stuck on the tentacle of the predator. Once stuck, it was unable to move away and the prey appeared to be pulled/pushed into the Hydra’s mouth, entering the coelenteron.

Daphnia magna also commonly known as water fleas are tiny freshwater crustaceans. They are filter feeders, and can survive in culture by eating algae, bacteria, or yeast. They feed plankton and detritus. There are about 1.5-5mm long. Daphnia Magna have a brood chamber where eggs are located. Daphnia magna are located in freshwater areas throughout northern hemisphere and south Africa.

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).

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.

We performed an experiment on crayfish focusing on their metabolic rates, via oxygen consumption, at two acclimated temperatures. Crayfish were either acclimated to a warm temperature (20 to 25C) or to a

The diatom Didymosphenia Geminata, often referred to as, “Didymo,” or “Rock Snot,” is native to many parts of the world. Didymo lives in freshwater streams and rivers and thrives in nutrient rich waters such as those that are in southern Missouri and Arkansas. This alga, not to be confused with algae, is a moss-like substance that until lately hadn’t been a cause for concern for anyone. Recently though, thanks mostly to anglers, Didymosphenia Geminata has begun to spread into rivers and streams that are, or at least were, not originally native habitats for this diatom. Scientists and ecologists are only now beginning to understand how damaging this substance really can be. While, “Didymo” has yet to be found in Missouri’s

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).

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 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.

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.

Didemnum vexillum colonies alter marine habitats and threaten to interfere with fishing, aquaculture, and other coastal and offshore activities. The colonies can grow on hard substrates that include dock structures and floats, wood and metal pilings, moorings and ropes, steel chain, automobile tires, polythene plastic, rocky outcrops, gravel seabed (pebbles, cobbles, boulders), and ship hulls. They overgrow organisms such as tunicates, sponges, macroalgae, hydroids, anemones, bryozoans, scallops, mussels, and oysters. Where these colonies occur on the seabed, they likely cover the siphons of infaunal bivalves and serve as a barrier between demersal fish and benthic prey. Colonies have been found at water depths ranging from intertidal to continental

The small shrimp, Hymenocera picta, is a general predator of all starfish and has been found to prey on A. planci at some locations. Pherecardia striata can only attack damaged A. planci and cause its death. Therefore, P. striata is regarded as a scavenger rather than as a predator. A. planci attracts many other scavengers who are able to tolerate A. planci’s horrible taste for the chance at a food source (Fisher 2011).