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If a population growing exponentially double in size in 3 years, what is the intrinsic rate of increase (r) of the population? |
Answer» A population grows exponentially if sufficient amounts of food resources are available to the individual. Its exponential growth can be calculated by the following integral form of the exponential growth equation: `N_(t)= N_(0) e^(rt)`. Where, `N_(t)` = Population density after time t `N_(O)` = Population density at time zero r = Intrinsic rate of natural increase e = Base of natural logarithms (2.71828) From the above equation, we can calculate the intrinsic rate of increase (r) of a population. Now, as per the question, Present population density = x Then, Population density after two years = 2x t = 3 years Substituting these values in the formula, we get: `rArr 2x= x e^(3r)` `rArr 2 = e^(3r)` Applying log on both sides: `rArr log 2 = 3r log e` `rArr (log2)/(3loge) = r` `rArr (log2)/(3xx 0.434) = r` `rArr(0.301)/(3xx0.434)=r` `rArr (0.301)/(1.302) =r` `rArr 0.2311 = r` Hence, the intrinsic rate of increase for the above illustrated population is 0.2311. |
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