WA 7 - Essay Example

The J- curve increases exponentially, reaches a maximum and then suddenly crashes to zero. J- curves are commonly seen in organisms that have very short life spans, and after laying eggs they die. The next generation of organisms that hatch from these eggs again follow a J- curve trend. Flies, mosquitoes are examples that exhibit this behavior. S- curves are seen in bigger animals such as mammals. The population grows steadily until it reaches stability. At this point the ecosystem is said to be in its carrying capacity.

The environmental resistance hinders uncontrolled growth in these animals. A. Competitive exclusion principle states that two species cannot exist together when they compete for the same resource. When this happens, either the more dominating species pushes out the other species, or the docile species undergoes a shift and moves onto some other resource. A. Owls are predators on the top of the food chain in the ecosystems where they thrive. Hence any distress in the bottom of the food chain is reflected in the owl’s population.

The majority of ecosystem which includes grasses, rodents and other small animals on which owls depend upon can be effectively studied by monitoring owls. A. Mutualism and commensalism are forms of symbiosis, where two organisms live in association with each other. In mutualism both the organisms are benefitted by associating, whereas in commensalism, one organism is benefited while the other is nether neither harmed nor benefitted A. Zero population growth rate is virtually impossible because, to achieve it the birth and death rates have to be exactly the same.

However the growth rate can be close to zero over a long period of time. A. The age structure diagram is affected by the birth and death rates of a population. Also the relative proportion of males and females in the population shapes it. The mortality rates at different cohorts affect the abundance of population in that cohort. 11. Is the clapper