Essay about Describe the physiological and subsequent ecological effects on living organisms and their populations of rising mean temperatures.

Submitted By ednasher
Words: 628
Pages: 3

Ecosystems are delicate communities of interacting organisms, and as such, factors impacting upon one part of it can cause knock-on effects throughout. Due to this, the increase in mean temperature in across the world may have a great effect on the populations living there. The direct effect of a temperature increase will be experienced on the molecular level initially. As the temperature rises, it causes the molecules, and atoms within them, to have more kinetic energy. This causes them to move faster, increasing the rate of diffusion as they collide more frequently with membranes and other molecules. It also increases the rate of reactions, not only because the increase of collisions causes an increase in successful ones, but also because the molecules collide with more energy, making reaction more likely. However, an increase in kinetic energy can also break the H-bonds in proteins, changing their secondary structure, and thus permanently changing their shape. This can change the active site of an enzyme, making it no longer have a shape complimentary to the substrate. The enzyme has then been denatured, and can no longer catalyse its reaction. Overall, a rise in temperature will initially increase the rate of most metabolic reactions, as most organisms’ body temperature is just below their optimum for enzyme activity, but then cause a permanent decrease in the rate of most metabolic reactions as the enzymes begin to denature. The denaturing of enzymes will reduce the rate of metabolic reactions such as photosynthesis and respiration, but it also lowers the affinity for oxygen of haemoglobin. This causes oxygen to be more readily unloaded at respiring tissues, increasing the rate of respiration, until the limiting factor becomes the rate of reaction due to the respiratory enzymes denaturing. This causes a decrease in the growth of organisms because they cannot respire to produce ATP as efficiently, and a decrease in plant growth due to the reduction in rate of photosynthesis. The mean temperature increase will cause water to evaporate from the leaves of plants at a faster rate, increasing the rate of transpiration due to cohesion tension. This provides more minerals for plant growth via the xylem, as they a brought up with the water. However, it also requires the plant to have a good supply of water, as otherwise, it may die due to dehydration. The result of this is that plants and animals grow less efficiently and there is therefore less…