AP BIOLOGY

Detailed explanation-1: -Population growth is the increase in the number of people in a population or dispersed group. Actual global human population growth amounts to around 83 million annually, or 1.1% per year. The global population has grown from 1 billion in 1800 to 7.9 billion in 2020.

Detailed explanation-2: -Overall, population grows or shrinks through two very basic components – natural change (births minus deaths) and migration (domestic plus international).

Detailed explanation-3: -The rate at which a population is increasing (or decreasing) in a given year due to a surplus (or deficit) of births over deaths, expressed as a percentage of the base population. A population in equilibrium, with a growth rate of zero, achieved when births plus immigration equal deaths plus emigration.

Detailed explanation-4: -Formula to calculate growth rate To calculate the growth rate, take the current value and subtract that from the previous value. Next, divide this difference by the previous value and multiply by 100 to get a percentage representation of the rate of growth.

Detailed explanation-5: -Usually, populations first grow exponentially while resources are abundant. But as populations increase and resources become less available, rates of growth slow down and slowly level off, reaching the carrying capacity. The carrying capacity is the upper limit to the population size that the environment can support.