Daphnia coursework

Contact Us Has the highest level of fitness and which has the poorest, and explain your answers. A number of variables.

Daphnia coursework

Figure 1 Figure 2 Figure 1: Anatomy of female Daphnia coursework pulex De Geer greatly magnified ; diagrammatic; muscles not shown in fig 1. Fig 1 was greatly modified from Storch, Photograph of a female Daphnia magna by John P.

Daphnia tend to be almost kidney shaped, possessing only a single compound eye though they have an ocellus, a simple eyetwo doubly-branched antennae frequently half the length of the body or moreand leaf-like limbs inside the carapace that produce a current of water which carries food and oxygen to the mouth and gills.

Their bodies Daphnia coursework almost transparent and with a microscope you can see the heart beating, and sometimes even their last meal the gut may appear green if the individual has been feeding on algae. A carapace covers the body, including the 4 to 6 pairs of thoracic appendages, and is used as a brood chamber.

The abdomen and post-abdomen distal to the anus is generally bent forward under the thorax. The post-abdomen bears two large claws used primarily for cleaning debris out of the carapace. Swimming is accomplished by downward strokes of the large second antennae. In most species complex movements of the thoracic appendages produce a constant current of water between the valves.

Small particles less than 50 microns in diameter in the water are filtered out by fine setae on the thoracic legs and moved along a groove at the base of legs to the mouth. Although there is some evidence that certain types of food, such as particular types of algae, Protozoa, or bacteria may be selected by some species, it is generally believed that all organic particles of suitable size are ingested without any selective mechanism.

When undesirable material or large tangled masses are introduced between the mandibles, they may be removed by spines on the first legs and then kicked out of the carapace by the post-abdomen. Males are distinguished from females by their smaller size, larger antennules, modified post-abdomen, and first legs, which are armed with a hook used in clasping.

Adult daphnia range in size from half a millimetre to almost a centimetre, depending on the species, though within a given species, size can vary greatly female Daphnia magna can be between 3 mm and 5 mm.

Colour is sometimes quoted in literature as a means of identifying species, but this can be a very vague indicator of species because within a species and even a strainthe colour of genetically-identical individuals can be quite different due to the adaptive physiology of Daphnids - in water which has low oxygen levels, Daphnia tend to develop more hemoglobin to increase their oxygen uptake from the water.

Individuals of the same strain in oxygen-rich environments tend to be yellow or almost unpigmented. An example of a species that seems to exist with very little hemoglobin in comparison to other members of its genus, is Daphnia hyalina.

It is usually found in the open water of lakes where dissolved oxygen is plentiful. The colour is also moderated by what food is predominating in the diet. Daphnia fed on green algae will be transparent-green in colour, while those feeding on bacteria will be salmon-pink.

The life span of Daphnia, from the release of the egg into the brood chamber until the death of the adult, is highly variable depending on the species and environmental conditions Pennak, Generally the life span increases as temperature decreases, due to lowered metabolic activity.

Daphnia coursework

The average life span of D. The average life span of Daphnia pulex at 20oC is approximately 50 days. Four distinct periods may be recognized in the life history of Daphnia: Typically, a clutch of 6 or 10 eggs is released into the brood chamber.

The eggs hatch in the brood chamber and the juveniles, which are already similar in form to the adults, are released in approximately two days when the female molts casts off her exoskeleton. The time required to reach maturity varies from 6 to 10 days.

Daphnia typically invest most of their energy in reproduction D. This serves to highlight the heavy emphasis on fast reproduction to take advantage of good conditions.

Daphnia coursework

What kinds are there? There are many different species of Daphnia and closely-related genera.Experiment to investigate the effect of caffeine Introduction I would be studying the effect of caffeine on the heart rate of daphnia over different period of time. Daphnia is the ideal medium because it is a tiny aquatic invertebrate which is transparent, so I see its internal organ and can monitor its heart rate (number of heart beat) by observing through a 5/5(2).

Daphnia Heart Rate LAB. A number of variables. TM How Does Temperature Affect Daphnia Heart Rate? On the heart rate lab, write a final report summarizing your question. • Concluding. Ceriodaphnia dubia, Daphnia magna, Pimephales promelas, Chironomus dilutus (formerly Chirono- mus tentans), Hyalella azteca, and Lumbriculus variegatus.

Daphnia is the small, planktonic crustaceans, which belong to the order Cladocera (Campbell and Jane 12). Their length ranges between to 5 mm. These organisms are among the many small aquatic crusteceans often called water fleas.

Daphnia magna is the species normally associated with the name Daphnia by most aquarists. It has been a favourite live food source since the hobby began. It has been a favourite live food source since the hobby began. DAPHNIA CULTURE MADE SIMPLE By Doug Sweet.

Instructions for maintaining daphnia cultures: Daphnia are one of the finest and most universally accepted live foods for most fish.

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Many fish species can be kept in excellent physical condition by feeding live daphnia to them several times per week. 2 determined Daphnia pulex behaved similarly to humans and are a dependable organism that could be used to test the effects of pharmaceutical substances on humans.

The study introduced the idea that Daphnia respond to pharmacological agents that are attributed with .

Investigating factors affecting the heart rate of Daphnia | Nuffield Foundation