explain the graphical representation of growth rate and also the mathematical formula for that!!sum1 plzzz**
A growth rate can be either Sigmoid (S shaped or logistic) or exponential. A logistic growth rate shows sigmoidal curve where there occurs an increase in the growth followed by a plateau. When organisms are introduced into a previously unoccupied area the growth of the population is first slow (positive acceleration phase) and then growth becomes very rapid (logarithmic phase). The growth then finally slows down as environmental resistance increases (negative acceleration) until an equilibrium is reached. Equation for logistic growth rate is:
dN/dt= rN (K-N/K)
where r: the intrinsic rate of natural increase
K: carrying capacity
N: Population density at time t.
J shaped growth curve (Exponential growth) has the density of a population increasing rapidly and then stopping abruptly as environmental resistance become effective more or less suddenly. Equation for the same is:
Nt= N0 (ert)
dN/dt= rN (K-N/K)
where r: the intrinsic rate of natural increase
K: carrying capacity
N: Population density at time t.
J shaped growth curve (Exponential growth) has the density of a population increasing rapidly and then stopping abruptly as environmental resistance become effective more or less suddenly. Equation for the same is:
Nt= N0 (ert)