Environment, Resources, and Competition
University of Phoenix Ecology and Evolution
BIO 315
January 14, 2011

Environmental Ecology
The ecosystem I choose to analyze is the tropical rain forest. These forests contain large trees and dense vegetation with warm temperatures year round accompanied by frequent rainfall.

Tropical rain forests also have very diverse species of plants and animals; there is a very high

level of biodiversity present there as well. Most trees have very short roots, particularly taller

trees, while others have deeper roots. The soil is very thin because the tree branches and leaves

keep the ground shaded and void of sunlight. This also makes it more challenging for smaller

plant life to thrive, due to a lack of rich soil needed for them to flourish. Thus, small plants and

shrubs that do survive must have qualities that make living without much tillable land possible.

Moreover, animal diets must not rely solely on small plants and shrubs, because they are of

limited supply.

The temperatures of the tropical rain forests are typically warm with an average yearly

low of 20C and an average yearly high of 34C. These temperatures are often accompanied

with constant rainfall. Tropical rain forests get an average yearly low of 200 cm of rainfall and

an average yearly high of 400 cm of rainfall; this combination create humid conditions under the

trees and at ground level (Smith & Smith, 2009). Precipitation and temperature play a large role

in this biome because they almost entirely determine what plants and animals are able to sustain

life there. They also establish high levels of biodiversity within the forests, fostering the homes

of many different species of trees and monkeys. Ultimately, both temperature and precipitation

are equally important because they balance one another.

The population of prey and predators fluctuates from year to year. During intraspecific

competition, the predator community suffers when there are limited supplies of prey available to

them for consumption. Therefore, the food supply is quickly depleted, causing the predator

population to decrease; there is a positive correlation between predator and prey in this

circumstance. High numbers of predator prey consumption translate to low numbers of available

prey, because they can be consumed faster. There is a negative correlation between predators

and prey in this circumstance. This predation creates competition between different species that

prey on the same food supply. The opposing species will be competing for the same prey,

forming more of a supply on demand environment and causing prey limitations. During interspecific competition, the graph suggests that the older the mother Felis catus

is, the higher chance of survival her offspring have; age of mother and offspring survival percentage are positively correlated (Smith & Smith, 2009). This offspring’s success may be because the older mothers have more experience and are able to teach their progeny more efficiently and provide them with more useful survival skills. A plausible scenario might be about a 40-month-old female monkey who has just delivered a baby about a month ago. This mother has lived in that forest for over three years and has gained experience about how to gather food, construct shelter, and avoid predators. She will be able to teach these survival techniques to her offspring, which will in-turn increase their chances of surviving in that environment. Interspecific competition might affect the reproductive success by making the resources shared by the different species more scarce. Pregnant animals require a certain amount of these resources in order for offspring to live to term. Additionally, newborn animals might find it extremely difficult to compete for resources against older more experienced animals and this could affect reproductive success as well.

The three graphs illustrate that a relationship exists between plants and animals. In the

sense of a predator/prey relationship, the animals would be the predators while the plants would

be the prey. On a more evolutionary standpoint, the plants eventually develop skills and

techniques that help them to disguise better, taste unappealing, or poison their predator to

increase their chances of survival. The plants’ inability to move or outrun a potential

predator causes this evolution of unique ways to avoid being eaten. In response, animals may

overtime acquire the abilities to recognize these disguises and build immunity to the poison in order to increase their chances of survival. This is an ongoing cycle where the relationship feeds

off of evolutionary advances experienced by both species.

References
Smith, T. M., & Smith, R. L. (2009). Elements of ecology (7th ed.). San Francisco, CA: Benjamin
Cummings/Pearson.