Phenomenal and rapid increase of population in a short period is called
Natural increase
Population growth
Population explosion
None of these
$I.$ Population evolve to maximise their reproductive fitness, also called Darwinian reproductive fitness (higher $r$ value), in the habitat in which they live
$II.$ The population growth rate $r$ is inversely related to generation time
$III.$ The housefly, which has a short life span and produces a large number of eggs, could be considered as a ' $K$ ' selected species
$IV.$ Under a particular set of selection pressures, organisms evolve towards the most efficient reproductive strategies
$V.$ Life history traits of organisms have evolved in relation to the constraints imposed by biotic and abiotic factors in their habitat Select the combination of correct statements
A biologist studied the population of rats in a barn. He found that the average natality was $250$, average mortality $240$, immigration $20$ and emigration $30$. The net increase in population is
Maximum survival and reproductive capacity shown by a population under optimal environmental conditions is called
In a population, unrestricted reproductive capacity is called
If natality is represented by $-B$
If mortality is represented by $-D$
If immigration is represented by $-I$
If emigration is represented by $-E$
If population density is represented by $-N$
Then population density at time $t+1$ is represented by