The Food Chain
In ecology, the food chain illustrates how energy and nutrients are transferred from one living organism to another in the forms of food. The smallest organisms are fed upon by larger ones, which in turn feed still larger ones, and so on. As you’ll learn below, the food chain is an elegant systematic arrangement that builds upon itself so that it can supply all living things with the amounts of energy that they need based on their sizes, activities, and life styles. In the end, the food chain becomes a cycle of life in which all energy sources break down to feed the earth, the cycle begins once again, and life continues. In the natural order things, this is how Mother Nature beautifully orchestrates the natural rhythms of self-sustaining ecosystems. Let’s look at each level of the food chain and how they function.
Producers are organisms that make their own food. In terrestrial food chains, they are plants, trees, bushes, grasses, and anything that has leaves. They are called autotrophs (from Greek, “auto” means “self” and “troph” means “feeding”) because they create energy by absorbing carbon dioxide from the air through their leaves and sucking up water and nutrients from the soil, with the help of fungi and bacteria. They use the sun’s energy to convert carbon dioxide into oxygen and water vapor that they then release through their leaves into the atmosphere. They are responsible for infusing energy into the food chain, making them the first link of the food chain. Without plants, all the other animals in the food chain would not exist.
Producers create energy in the forms of glucose (a form of sugar), amino acids, proteins, and fats, which they store inside new cells that are made using the nutrients (nitrogen, sulphur, and phosphate) they took from the soil. Those nutrients affect how fast plants grow.