Tricia Dietrich

Biology II T-TH

Every living organism needs oxygen, water, energy, and nitrogen. The organism also needs to get rid of carbon dioxide, and nitrogenous wastes. So how do the Coast Redwood and Bald Eagle attain these essentials?

The coast redwood, as in all plants, receives its necessary essentials either through the roots or the leaves. The roots absorb water, trace minerals, nitrogen, phosphorus, and through the soil, and take in oxygen and expel carbon dioxide with air spaces in the soil by diffusion. Leaves take in carbon dioxide for photosynthesis and expel oxygen through the stomata. The needed sugars are produced in the leaves by photosynthesis. These essentials need to be transported cellularly, laterally, and to the top of the plant. On the cellular level passive and active transport is used to achieve this. Passive transport is when the solutes diffuse down their gradients across the membrane, and no energy is required for this method. This is the way water is transported. Active transport is the movement of the solute against its concentration, and this method requires the use of energy (Campbell 693). There are three methods to transport water and minerals laterally. One is when solutes move across the cell wall into the next cell. This requires the solute to repeatedly cross the plasma membranes. Another method is through the symplast, which is the continuation of cytoplasm within the plant tissue, and requires only one crossing of the plasma membrane. The last method is the movement of water and minerals along the apoplast, which is the extracellular pathway between cell walls, and does not require the solute to cross the plasma membrane. Now the water and minerals need to get to the leaves at the top of the plant. Bulk flow, the movement of materials from high to low pressure, is used to accomplish this. The leaves transpire or get rid of water causing the pressure in he leaf to drop. This makes the pressure in the roots higher than that of the leaves, making a vaccum, causing the water and minerals to move up the xylem as xylem sap at one meter per hour (Campbell 697). Nitrogen is also transported in this fashion. Sucrose, the energy source, moves along the pholem in a pressure flow form the source to sink. In the source part of the pressure flow, the sucrose is pumped into the leaf portion of the pholem. The water follows gradients by osmosis, and a high pressure develops in pholem. In the sink portion of the pressure flow, sucrose is consumed for energy, and water moves along its concentration gradient reducing the pressure in the pholem. Even the tallest tree in the world, the coast redwood, works using the same methods as an incredibly small plant.

The Bald Eagle, as with all animals, also needs the same simple essentials. The eagle uses its digestion, circulatory, and urinary systems to obtain and dispense these materials. The eagle has a mouth, esophagus, crop, stomach, gizzard, intestine, and anus. The esophagus us wide in the eagle and also acts as a food storage area when large amounts of food are consumed. The eagle also has an extra storage area in the esophagus called the crop. The stomach of the eagle has two chambers, the proventriculus, which produces gastric fluids for chemical digestion, and the gizzard, which mechanically digests food. The wall of the gizzard in the eagle is extremely thin and sac-like because the fish is much easier to digest. The gizzard also traps indigestible particles such as bones, teeth, and feathers, and compacts them into pellets, which are then regurgitated. For the food to be completely digested, it is moved back and forth between the two chambers of the stomach. The intestine completes the final process of digestion and then nutrients are absorbed through the gut wall. Both the liver and the pancreas are larger than those of mammals. The eagle has a closed circulatory system, which means that the blood stays within the wall of the blood vessels. The blood is pumped throughout the body by a four chambered heart. The heart of an eagle is much stronger than the heart of a mammals because of the higher metabolic rate needed for flight. The body temperature of the eagle ranges form 100.4 F to 107.6 F. They maintain this temperature by three different methods. First the arterial blood passes heat to venous blood, therefore cooling the outgoing blood and warming the incoming blood; which lessens the heat loss in areas without feathers. To stay warm the eagle can increase metabolism and fluff its feather to trap warm air. To stay cool the eagle can decrease metabolism and flatten its feathers to release trapped air, or it can pant. The eagle has the best respiratory system of all animals because of their ability to fly. The eagle has lungs and also extra air sacs. Two cycles of inhalation are required for the air to pass throughout the bird. In the first inhalation, air passes past the lungs and enters the posterior air sacs, air then moves into the lungs during exhalation. In the second inhalation, the air from the first inhalation goes into the anterior air sacs and new air enters the posterior air sacs, air from the anterior air sacs moves out the lungs during exhalation. This completes a full cycle of breathing. The function like those in mammals. Uric acid is produced as the final waste (Sea World 2-3).

Campbell, Neil A. Biology. Fourth Edition. Menlo Park, California:

Benjamin/Cummings Publishing Company, 1996

"Anatomy and Physiology." Sea World/Busch Gardens. (1997): 4pp. Online. Internet

23, March 1998