Desert Food Chain
or Food Web

An Introduction

A Food Chain, or Food Web is how biologists describe the series of living organisms that energy passes through as it powers the lives of plants and animals. A food chain always begins with plants, called producers. It always ends with animals, called consumers.

The food chains of Southwestern deserts work just like the food chains of forests, grassy plains, swamplands or any other region.

Energy and the Food Chain

Solar energy is combined by plants with water and carbon dioxide to create glucose. Glucose is a form of sugar used by animals for reproduction and growth.

The First Link in the Food Chain - Producers [Plants]

Plants, or producers, capture the energy from the sun and are the first link in the food chain.

Energy is essential for the growth of all organisms, the processes of life and the actions of animals. Energy enters the food chain through plants, as they capture and change the energy of the sun.

Energy creates the power to make something to happen, like breathing, or movement. Energy is used by plants to grow and to reproduce. It's used by animals too, to grow, to reproduce and to move. People use energy too, just as animals do.

Energy exists in two ways:

1) Potential energy is energy that's stored, like a savings account, available for spending. Potential energy is stored, for example, in a battery, an apple or in gasoline.

2) Kinetic energy is energy that's being spent to cause something to happen, like growth, reproduction or movement.

Solar energy is combined by plants with water and carbon dioxide to create glucose. This is called photosynthesis, a word that means “gathering of light.” Almost every plant from the smallest to the largest uses photosynthesis.(Some parasitic plants such as Indian pipe, Monotropa uniflora, and the snow plant, Sarcodes sanguinea, do not use photosynthesis, getting their energy instead from their host plant.)

A prickly pear cactus has a waxy coating that slows evaporation and saves water.

The Second Link in the Food Chain- Herbivores [Animals that Eat Plants]

Energy begins to flow through the food chain when plants are eaten by animals, like insects, reptiles, birds, or mammals. Animals that eat only plants are called herbivores. They are the second link in the food chain.

Bee on Cactus Flower

A bee, feeding on plant nectar, is an example of the second link in the food chain.

The Third Link in the Food Chain - Carnivores [Animals that Eat Animals]

Energy moves through another link in the food chain when animals such as spiders, snakes, and hawks eat an herbivore. Animals that eat only other animals are called carnivores. They are the third link in the food chain.

Ladybug

A ladybug eating aphids is an example of the third link in the food chain.

The Fourth Link in the Food Chain- Carnivores, Omnivores [Animals that Eat Plants and Other Animals] and Scavengers [Animals that Eat Dead and Decaying Organisms]

Energy moves through still another link with carnivores that eat other carnivores. These include spider wasps, which may hunt tarantulas; snakes, which may eat other snakes; eagles, which may eat goshawks; and gray foxes, which may eat shrews. These carnivores are a fourth link in the food chain.

Energy moves in even more different ways with animals that eat both plants and other animals. These include earwigs, which eat flowers and flies; collared lizards, which eat various fruits and insects; gila woodpeckers, which eat fruits and insects; and coyotes, which eat fruits and small animals. These animals, called omnivores can be a second, third or fourth link in the food chain.

Energy moves in yet another direction with animals that feed on dead and decaying organisms. These animals, called scavengers include a variety of species, ranging from earthworms, which feed on dead and decaying plant tissue, to turkey vultures, which eat dead and decaying animal carcasses.

Diamondback Rattlesnake

Diamondback rattlesnakes eat small mammals and reptiles. They can be third or fourth links in the food chain.

The Final Link in the Food Chain - Decomposers [Animals that Eat Dead Plant or Animal Tissue or Waste]

Energy moves through the final link in the food chain with microscopic animals called decomposers, which feed on any remaining dead plant and animal tissue and animal waste. Over time, these tiny fungi and bacteria break down decaying organic matter, converting it into carbon dioxide and water. The freed carbon dioxide and water are then available again for plants to use in the process of photosynthesis. This makes it possible for the cycle of energy to move through the living community all over again.

Energy follows constantly changing routes throughout food chains. Communities of plants and animals may be made up of tens of thousands of species that change with the seasons and the years. This process forms an interlocking web of food chains.

Video on how the Desert Food Chain Works

Desert Thunderstorm

Desert thunderstorm brings welcome rainfall.

by Jay W. Sharp

Food Chain Introduction
How Do Green Plants Manufacture Their Own Food?
How Do Desert Plants Survive?
How Do Desert Animals Survive?
The Arithmetic of the Food Chain
The Classification of Desert Plants & Animals

Note: My thanks to Leslie Bergloff, a former teacher and the present New Mexico Farm & Ranch Heritage Museum Education Coordinator for her helpful comments in preparing this article.