Learn about the Differences Between Autotrophs and Heterotrophs

By Jarod Saucedo

Need to distinguish an autotroph from a heterotroph? Read this study guide to learn about the various differences as well as the fact that you are a heterotroph and depend on autotrophs for survival.

Role of Organisms

There are a variety of organisms that have a mutual relationship in providing for others. In this context, an organism is either a producer or a consumer in the environment. Producers make their own food by using energy. For example, a green plant takes in the sun's rays, carbon dioxide, and water to make glucose using photosynthesis which it uses as a form of energy and food. Consumers, such as herbivores (plant eaters), carnivores (meat eaters), and omnivores (plant and meat eaters) often consume producers in order to get energy.

With this mutual relationship, the sun provides energy for the producers which in effect also provide energy for consumers. A food pyramid comes out of this relationship with producers at the bottom, followed by herbivores, then carnivores, and finally omnivores. An interesting thing to note is that at each step, only about 10% of energy is transferred to the next level. For example, if a herbivore eats a plant, it only gains about 10% of the energy that the sun provided for the plant.

So how does one distinguish between an autotroph and a heterotroph?


Autotrophs Producers are often called autotrophs because they can make their own food. Autotrophs do so by taking in sunlight, carbon dioxide, and water where they use photosynthesis in order to make glucose and other sugars. Examples include a variety of plants as well as certain bacteria which also use this process in order to make food.

In relation to heterotrophs, autotrophs are important because they are the foundation of food for heterotrophs. In return, heterotrophs can break down the food molecules to convert their own form of energy. Without autotrophs, heterotrophs would not be able to survive.

One interesting fact about autotrophs is that they do not have to rely on any other food source besides their own needs. For example, a plant only needs sunlight, carbon dioxide, and water to survive. Therefore, they are the foundation of all food chains.


So where do consumers fit into this picture? Consumers are often called heterotrophs because they consume autotrophs in order toHeterotroph  survive. For example, let's say a cow eats grass for energy. They consume a large amount of grass where it travels to their stomach. It is here where the food molecules are broken down and the cow uses these food molecules to make energy. Like previously stated, a cow will only receive about 10% of the energy from the grass.

There are a wide range of heterotrophs. Examples include herbivores such as dinosaurs who eat plants, carnivores such as lions who eat herbivores or carnivores, and omnivores such as human beings who can eat autotrophs, herbivores, carnivores, and even other omnivores! Another category is decomposers such as vultures and bacteria which eat or break down dead herbivores, carnivores, or omnivores.

It is interesting to see how the transfer of energy is so inefficient when it comes to this particular food chain. For example, let's say a lion eats a herbivore. The lion will only receive 10% of the energy from the herbivore which only received 10% of energy from an autotroph. The autotroph had the best form of energy where it received 100% energy from the sun.

Even though there are differences between autotrophs and heterotrophs, they still depend on each other.



MC Biology. "Environmental Biology-Ecosystems." http://www.marietta.edu/~biol/biomes/ecosystems.htm

Taggart, Ralph E. "Life and Energy." http://taggart.glg.msu.edu/isb200/energy.htm


柑橘類. "Plant Diversity." http://commons.wikimedia.org/wiki/File:Plants_diversity.jpg

Cgoodwin. "Beef Shorthorn." http://commons.wikimedia.org/wiki/File:Beef_Shorthorn_calf.jpg