Tuesday, August 12, 2014

Population Growth

Exponential Growth
Definition: is a type of growth curve when a population is constantly increasing with no factors that limits its growth. The graph of this line is in a J curve that rises from the left to right. This type of curve when there is an infinite amount of  resources are available in an environment. The rate of growth will be increasing each year because resources keep on being available. 
Example: The temperate deciduous forest contains bacteria which grow at an exponential rate. In particular the forest contains paramecium, bacterium and amoeba. Bacteria grows exponentially in the temperate deciduous forest because bacteria grows high in a fresh medium when a given number of cells are present. This forest is rich with fresh medium, it consist of one of the most richest soils and bacteria loves to inhabit itself in it. This forest is always growing due to constant rain during summer and spring times. 


Logistic Growth & Carrying Capacity
Definition: is a type of growth curve that will start slow and then keeps increasing until it finally tappers of at its carrying capacity. The carrying capacity is the amount of organisms an ecosystem can sustain without becoming overpopulated and loosing resources. Logistic growth is in the form of a S-Curve. This is the most common type that is found in biological populations. 
Example: The White Tailed Squirrel is an example of an r-selected species. If this population of white tailed squirrels started of with just a few members but then found a steady source of food. This population of squirrels would then start to grow rapidly and reproduce at a steady rate. Then if a natural disaster such as a hurricane comes by, it would diminish the food source which would lead to the population tapering of at the carrying capacity. 


Age Structure Pyramids
Definition: shows the chance of living in a population through each age group. In the temperate deciduous forest there weren't any depictions of animals for age structure diagrams. This is why a survivorship curve is a much accurate representation of what organisms live and survive in this biome. A survivorship curve is a graph that measures the number of organisms that  will be alive a different age groups. There are three types which are type 1, 2, and 3

Example: In the temperate deciduous forest type 2 organisms are commonly present. These type of organisms have an even chance of dying throughout their life span. There chance of dying is independent of age so the mortality rate is constant throughout there entire life. In the deciduous forest species that display this behavior is the White Tailed Squirrel and the Red-Tailed Hawk.

No comments:

Post a Comment