Students should be able to describe some of the biological factors affecting levels of food security. • Food security is having enough food to feed a population. • Biological factors which are threatening food security include: the increasing birth rate has threatened food security in some countries; changing diets in developed countries means scarce food resources are transported around the world; new pests and pathogens that affect farming; environmental changes that affect food production, such as widespread famine occurring in some countries if rains fail; the cost of agricultural inputs; conflicts that have arisen in some parts of the world which affect the availability of water or food.