Several assumptions can be made about the movement of molecules from the region of higher concentration to the region of low concentration to form equilibrium between the two sides. Some of the molecules we can test for permeability may include starch, glucose and protein. To test for the movement of starch in the dialysis tubing with starch solution to the lower concentration region of starch for example water in a beaker, iodine potassium iodide (I2KI) is used. The presence of starch in the unknown solution can be ascertained when the I2KI is added to the solution and the color of the solution finally turns black or purplish. If it remains pale yellow-amber color (color of dilute I2KI) then there is absence of starch. The assumption is always that the solution outside will always test negative for starch since the starch molecules are large that they cannot pass through the semi permeable membrane of the dialysis tubing.
To test for the presence and permeability of glucose, glucose solution is put in a dialysis tube and placed in a beaker of water and after some time the solution in the beaker is tested for the presence of glucose using Benedicts reagent to test for reducing sugars and this is possible since glucose is a monosaccharide which are reducing sugars. Therefore to test for glucose, the solution in the beaker will be mixed with the benedicts solution and then heated. If the solution turns green, red or orange then there is presence of glucose and if it remains blue there is absence of glucose. However the test is semi-quantitative since the red color showcases relatively high concentration of glucose while the green color reveals relatively low concentration of glucose. Normally this solution may remain blue due to the large molecules of glucose which cannot pass through a semi permeable membrane unless they dissolve in water.
To test for the presence and permeability of protein which is a polymer of amino acid, a bluret test is used. A solution with protein in dialysis tubing is placed in a beaker of water and later the solution in the beaker is tested for the presence of proteins using bluret test. The solution will turn violet if there is presence of proteins with an addition of bluret otherwise it will retain the color of bluret. However due to the larger molecules, we would presume that there will be no proteins in the beaker.
Every organism survives through natural selection due to their variations in traits. The European hares which are from the same family as rabbits belong to the genus Lepus. They are less social than bunnies and have a lively skittish and courtship behavior. Some time back there lived brown hares in a cold snowy polar region and due to their color there were easily spotted and killed by other animals for survival. These hares struggled to survive and compete for their life. Each hare was different from other hares and after some time there was mutation of genes and there came into being a few albino white hares.
Through natural selection the white albino hares were able to survive since there predators were not able to spot them because they looked similar to the snow thus taking advantage of camouflaging. They were able to adapt to this environment and therefore reproduced. In the future white hares became dominant because there genes were able to be inherited over a long period of time. During this generation more and more white hares reproduced and passed the heritable albino trait to their young ones. So the brown hares came to an extinct due to natural selection. Therefore after some time the entire population was made up of white hares.
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