Water comprises a very large part of an organism's body. The delicate balances within the systems of an organism involve the concentrations of, to name a few, Na+, K+, Cl-, and Ca2+ salts (Dilger and Collins, p. 9). There are two types of fluids within organisms; the ICF (intracellular fluid) and ECF (Extracellular fluids). Every organism regulates the tonicity of the ICF. However, the ECF can be regulated or non-regulated. Organisms fall into two categories based on this distinction. These categories are the osmoconformers and the osmoregulators (Dilger and Collins, p.9). Osmoregulators have special mechanisms to keep their BFOC (Body fluid osmotic concentration) constant, independent of the EOC (environmental osmotic concentration). Osmoconformers, on the other hand, have a BFOC that is directly related to the EOC ( Dilger and Collins, p.9).
[...] In 125%, they lose water to the saltier surroundings and lose weight. The trendlines support this. The clams are osmoregulators, and so in 100% and in 75% their weight changes little overall. In 125%, however, they seem to gain weight according to the graph. The following pages show the graphs and tables for change in weight and percent change in weight. 75% Salinity Time Worms - Change in Weight in Grams Discussion At the conclusion of this lab, there are some confirmations of the hypothesis and some discrepancies. [...]
[...] If the worms were placed in an environment of much higher or lower concentration of salt than in this experiment, they would either burst (if the solution has too little salt), or shrivel and die (if the solution has too much salt). It should be noted that the worms data was provided to us, and these measurements are not ours. This may explain why they perfectly comply with the hypothesis. The clams show a somewhat more mixed result. At 75% isotonic, the clam's weight stays more or less the same as seen in the graph. [...]
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