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Why Are Plants Called Autotrophs? (All you need to know)

Have you ever wondered why we give water to plants? Necessary conditions that plants need to grow and thrive, what do they do for the plants? Those conditions such as enough sunlight, water, nutrition, and carbon dioxide are given to plants so they can make their food. And for this very reason, plants are commonly known as autotrophs.

The term autotroph will mean nothing to many people, while others might have heard it but would not know what it means exactly. An autotroph is another name for green plants. This could leave you wondering why are plants called autotrophs? If you can’t wrap your head around this, keep reading as we are here to answer this exact question – why are plants called autotrophs?   

Why Are Plants Called Autotrophs 1
Auto-and heterotrophs – via Wikimedia

Why Are Plants Called Autotrophs?

Most plants are given the name autotrophs due to their special abilities. Autotrophs cover more creatures than just plants, and not all plants are autotrophs. Plants are living things, and they need food to survive. They cannot soak up or eat human food through an organ. So, where do they get enough nutrition and glucose to grow and convert into fruits and vegetables?

The answer to that question lies in autotrophy. It is a vast, self-sustaining concept. Let’s find out more about autotrophy and why are plants called autotrophs?

What Are Autotrophs?

Autotrophs are any living things that can create their food, which means that they do not depend on other creatures to feed them, produce food for them, or bring them food. Green plants are the main living things that fall under the category of autotrophs as they produce their food.

However, not all plants are autotrophs which means that not all plants can make their food. Most plants can make their food through photosynthesis, but some plants can’t carry out the process of photosynthesis. These plants are called non-photosynthetic and parasitic as they use a special host to get their food.

The parasitic plants have specialized organs, which are called Haustoria. These organs penetrate and infiltrate the host plant’s tissue and suck out the water and nutrients from it.

Other than these parasitic plants, most plants are green plants. This green color is given to them through chlorophyll, and they use it to make their food via photosynthesis. Green plants are not the only autotrophs among the creatures. There are some other examples too that can perform the process of photosynthesis. 

Examples of Autotrophs

Some other examples of autotrophs besides plants include algae and most kinds of seaweed. Certain bacteria and fungi can also perform the process of photosynthesis in their cells. Green algae, bacteria, and seaweed undergo photosynthesis in the same manner as the plants go through it.

According to some research and evidence, phytoplankton is also called autotrophs. Phytoplankton is a tiny creature that is a bit like a plant and is found in the ocean. Jellyfish, shrimp, snails, and other water creatures feed on the phytoplankton.

You can consider them tiny water algae. These plant-like creatures can’t be easily seen with the naked eye, and they float near the surface of the water to catch the incoming light to produce their food.   

Humans and animals are not autotrophs.

Why Are Plants Called Autotrophs
Meal worm in venus fly trap – via Wikimedia

How Do Autotrophs Produce Their Own Food?

Green plants are the most common form of autotrophs, and they use the process of photosynthesis to produce their food. There are organelles inside the plants, called chloroplasts, and they help the plant convert light into nutrients. Moreover, the organelle uses carbon dioxide and water to produce glucose, which is a simple sugar used to provide energy and oxygen on the side.

Glucose is a simple sugar that is a source of energy for the plant to grow and flower and for the people consuming the plant as food.

Photosynthesis is not the only process used by autotrophs to produce food. Some bacteria that are categorized as autotrophs use chemosynthesis to produce their food. Instead of light and carbon dioxide, chemicals like methane or hydrogen sulfide are used in combination with oxygen to produce carbon dioxide and energy.

This process of chemosynthesis is also called oxidation. These are not the common form of autotrophs and are usually found in extreme environments.  

Autotrophs vs. Heterotrophs

autotrophs are known for producing their own food via photosynthesis, while heterotrophs are those organisms that cannot produce their food. Heterotrophs can’t take up inorganic materials and produce organic food in return like autotrophs. They need to consume pre-made organic items to produce energy.

Both autotrophs and heterotrophs are a necessary part of the environment to maintain the balance of the ecosystem. They have different functions to perform and gain energy from different sources, but they contribute to the balance of the ecosystem in their way. Their contribution becomes clearer when we look at the food chain and the different levels at which both the autotrophs and heterotrophs reside. 

Autotrophs and the food chain

Scientists have classified organisms into groups based on which creature eats which organism in the wild, and different classes have been grouped owing to their nutrition or trophic levels. These are arranged in a pyramid. Autotrophs lie at the first level of the pyramid as they don’t feed on anything but make their food. Therefore, they are also called the producers.

Herbivores feed on autotrophs, carnivores eat animals, and omnivores eat plants and animals. Herbivores lie at the second level of the food chain. All food chains start with some autotroph to feed others. The more autotrophs there are, the more animals there will be that eat them.

Why Are Autotrophs Important?

Autotrophs are essential to carry the food chain and hence, the life on the planet forward. There would be no life without autotrophs as there would be no herbivores to feed on them. Without herbivores, there would be no carnivores or omnivores.

Autotrophs are the source of all complex life on earth, if not directly, then indirectly, as all creatures’ diets can be traced back to green plants.


I hope this answers your question of why are plants called autotrophs. Plants are the primary source of food and life on our planet. There are several more benefits of plants around us other than food. So, make sure to keep planting more of these autotrophs in your garden and other parts of the environment.