Population Growth and Competition in Lemna sp. and Spirodela sp.1
Joane C. Tampoco
Group 3 Sec. U-1L
August 8-29, 2009
1A scientific paper submitted in partial fulfillment of the requirements in Ecology laboratory under MS. Faith Maranan, 1st sem., 2009-2010. INTRODUCTION
Population growth is the change in population over time, and can be quantified as the change in the number of individuals in a population using "per unit time" for measurement (Wikipedia.com). A population can grow in an exponential or logistic growth pattern. Exponential population growth is the geometric increase of a population as it grows in an ideal, unlimited environment. For a continuously reproducing population, exponential growth is an excellent first-approximation of population growth. When resources are not limiting, and interspecific competition is at a minimum, many populations of organisms grow exponentially. This generally occurs when populations are at densities far below their environmental carrying capacity, which is the maximum number of individuals a given environment can sustain (IUC. edu). The outcome of n exponential growth can be determined by the intrinsic rate of increase which is the difference between the birth rate and death rate. If the rate is greater than zero, the population increases exponentially. If it is less than zero, the population exponentially decreases, and if it is equal to zero, the population remains constant. In reality, populations do not appear to increase in an unlimited manner. Instead, populations are limited in their numbers by the availability of the resources or by the carrying capacity. With high number of species, intraspecific competition, that is, competition among similar species, intensifies. While the intrinsic rate of increase was assumed to be constant in the exponential growth equation, when intraspecific competition is...
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