Final Exam Biology - Assignment Example

The primary consumers will have all the energy from the sun and synthesize nutrients. These nutrients will be used by each level with little being passed to the next trophic level hence the biomass will decrease. Considering the concept of ecological efficiency, only about ten per cent of the nutrients and energy passed to a given trophic level will be utilized. Therefore, that will be lost with the one in the next trophic level being smaller by ten percent. This is the main reason why the pyramid will rarely have more than seven trophic levels.

The acacia ants live in the thorns. The acacia produce the substance that the ants use for food. On the other hand, the ants defend the acacia from herbivores by stinging them. Therefore, when the ants were removed, the acacia left could have been destroyed by herbivores with their height remaining limited. The ants also prune other plants that grow under the acacia making them dominant. This explains the information presented on the graph. Dead zones are also called hypoxic zones. They exist in oceans where there is low oxygen concentration such that aerobic organisms living there die due to lack of oxygen.

Dead zones are formed due to an interaction between biological, chemical and physical factors. Nutrients from agriculture and urban development are washed off to the water bodies such as the ocean. The excess nutrients fertilize the quick growing microscopic plants in a process known as eutrophication. Once all the nutrients are used up by the phytoplankton, they sink to the bottom and decompose. The decomposition process by the aerobic bacteria depletes the oxygen making the region hypoxic. This leads to the formation of dead zones.

Hamilton addressed the issue of altruism to develop the equation above. His approach considered that provided there is a genetic basis for altruistic tendencies should-via the principle of independent assortment-produce siblings with a particular probability