i. The concept of a population ceiling, first suggested by Malthus, is of a saturation level where the population equals the carrying capacity of the local environment.
Three models portray what might happen as a population, growing exponentially, approaches the carrying capacity of the land.
ii. The rate of increase may be unchanged until the ceiling is reached, at which point the increase drops to zero. This highly unlikely situation is unsupported by evidence from either human or animal populations.
iii. Here, more realistically, the population increase begins to taper off as the carrying capacity is approached, and then to level off when the ceiling is reached.
It is claimed that populations which are large in size, have long lives and low fertility rates conform to this ‘S’ curve pattern.
iv. In this instance, the rapid rise in population overshoots the carrying capacity, resulting in a sudaen check e.g., famine and reduced birth rates-which causes a dramatic fall in the total population.
After this, the population recovers and fluctuates around, eventually settling down at, the carrying capacity. This ‘J’ curve appears more applicable to populations, which ar^ small in number, have short lives and high fertility levels.
v. The carrying capacity is the largest population of humans/animals/plants that a particular area/environment/ecosystem can carry or support.