EVERYDAY SCIENCE

Detailed explanation-1: -These density-independent factors include food or nutrient limitation, pollutants in the environment, and climate extremes, including seasonal cycles such as monsoons. In addition, catastrophic factors can also impact population growth, such as fires and hurricanes.

Detailed explanation-2: -Overfishing and hunting, the destruction of habitats through agriculture and urban sprawl, the use of pesticides and herbicides, and the release of other toxic compounds into the environment have all taken their toll, particularly on vertebrates.

Detailed explanation-3: -Causes of population decline The size and demographics of the population change when: fewer children are born; families with children move to larger towns and cities; young and better-educated people move to larger towns and cities.

Detailed explanation-4: -A reduction over time in a region’s population can be caused by sudden adverse events such as outbursts of infectious disease, famine, and war or by long-term trends, for example, sub-replacement fertility, persistently low birth rates, high mortality rates, and continued emigration.