Some factors may cause a decrease in food supplies, thereby having an adverse effect on the population. In any habitat, producers provide the food that supports all consumers, either directly or indirectly. However, certain environmental factors can decrease the food supplies of some of these populations, causing food shortages.
Meaning of Food
Food is any nutrient-rich material consumed or absorbed by living things to sustain life and growth. The major sources of food are animals and plants. It is consumed because it provides energy and nourishment and keeps humans and animals healthy.
Read: Classes of food
Causes of Food Shortage
Disease: This is one of the factors that can bring about food shortage. A highly contagious viral disease can kill large numbers of crops. This causes a shortage of food for people that feed on such crops.
Drought: this causes scarcity of water, and without water, most plants die. If the drought lasts for a long period, the primary consumers start to die or emigrate to other areas, causing a food shortage for secondary consumers.
Effects of Food Shortage
Increased Mortality: Food shortage increases death rates, especially among the young and the old – the vulnerable age groups.
Emigration: Another outcome of food shortage is emigration. This is the movement of members of a population away from its habitat to various other areas as a direct response to a lack of food or living space. It occurs at irregular intervals, and there is no return movement as in migration. Individuals only emigrate if their chances of survival are better by doing so than by staying in the habitat.
Rate of Reproduction: The reproductive rate is the rate at which new individuals are produced. Food shortage lowers the rate of reproduction and delays sexual maturity. Growth is retarded during food shortages. This often delays sexual maturity, which seems to be more related to size than to age in some species. Under starvation conditions, many female humans stop ovulating and so would not be able to conceive.
Competition: During a food shortage, members of a population will compete with one another for the limited food supply. Only the most vigorous individuals succeed in getting food, the rest starve.
