Onur Baykal 3-10-14 Class: 44s
Homework #24 – Plant and Animal Essay Questions
1. In general, respiration refers to the process by which organisms undergo gas exchange. More specifically, in order for an organism to complete the process of respiration, a continuous source of oxygen is required, and as such many different organisms have undergone various structural and physiologic alterations for the taking in of oxygen. One specific living organism, which has endured such adaptations for oxygen intake, is a fish. On the notion of structural adaptations, fish have developed gills, which are in effect respiratory organs, that enable fish to extract the dissolved oxygen found in their surrounding aquatic environments. An additional structural adaptation, comes from the presence of a Operculum in various fish species. By definition, the Operculum is a structural flap, composed of bone, that basically covers and protects the gills of the fish. Furthermore, the Operculum is also capable of functioning as a “seal,” to eliminate the occurrence of a reversal in water flow though the gills during respiration. In terms of Physiological adaptations, many fish utilize a countercurrent mechanism of gas exchange. In other words, oxygen exchange in fish simultaneously occurs in two opposing directions of gas flow, as fish exchange oxygen gas through their gills within their aquatic environments. An additional physiological adaptation, comes from how fish utilize the iron rich, protein molecule Hemoglobin, for holding and transferring oxygen throughout their bodies, in their process of gas exchange.
Besides fish, trees have also undergone structural and physiological adaptations for the uptake of oxygen. One example of a structural adaptation, is the presence of stomates on the leaf surfaces of trees. Specifically, stomates are pores, which allow essential gases, namely Carbon Dioxide, to be sufficiently exchanged, and bypass the wax based barrier known as cutin, which exists on many plant surfaces, so that photosynthesis can proceed. Furthermore, stomates are bordered by guard cells, which aids in their functioning. An additional structural adaptation for trees, comes from the tree's epidermis, which is a protective boundary which separates a plant from its exterior surroundings. In terms of gas exchange, this “protective layer” is permeable to oxygen, so that the exchange of oxygen is allowed to proceed as part of photosynthesis. In terms of physiological adaptations, tress have mechanisms by which stomata are regulated. More specifically, the opening of stromata are regulated by light energy conversions, as well as the buildup of Potassium Salts and sugars within the guard cells. These phenomena are controlled by proton pumps in the cell membrane. An additional physiological adaptation, comes from how the large, wet interior Mesophyil surfaces in trees, provide for a large surface area for gas exchange to incur.
Finally, structural adaptations for gas...