Similarities between Heterotrophs and Autotrophs

In this similarities between heterotrophs and autotrophs post we have briefly explained about autotrophs vs heterotrophs, flow of energy, photosynthesis, and cellular respiration. Read on to learn more about autotrophs vs heterotrophs!

Earth is home to numerous creatures, including humans. This raises questions about what these creatures eat. What is the basis of their food, or what is their growth process? In years of research and study, we have come to a classification of organisms based on the principle of where they obtain their nutrients from. Therefore, they are divided into two types of autotrophs and heterotrophs. 

The latter is a secondary or tertiary customer within the food chain. For instance, plants, algae, etc. However, they are the major food producer in the chain. Examples include animals such as horses, dogs, lions and others. We will also discover the difference between heterotrophs and autotrophs, along with their definitions and other information.

Autotrophs vs Heterotrophs


Autotrophs as shown in the figure below contain chemical energy in the carbohydrate molecules that they make themselves. Food is the chemical energy that is stored within organic compounds. Food supplies the energy required to perform work and carbon for building the bodies. 

Since most autotrophs convert sunlight into food, we can call the process they utilize the process of photosynthesis. Only three organisms, namely, algae, plants, and a few bacteria, can transform this vital energy. Autotrophs produce food for themselves and produce enough food to sustain other living things. 

Nearly all other species depend completely on three of them for their food sources. These three groups, also known as producers or autotrophs, also called; start with food chains that feed all living things.


Heterotrophs are unable to create food from scratch. Therefore they have to eat or take it in. Because of this, heterotrophs are often referred to for being a consumer. Consumers include any animal as well as the protists, as well as many bacteria. 

They could consume autotrophs or other heterotrophs, organic molecules produced by other species. Heterotrophs have a variety of species and can be superior to the producers. However, heterotrophs are limited due to our dependence on autotrophs that make our food. 

If algae, plants, and autotrophic bacteria disappeared from earth and the environment, animals, fungi and heterotrophs like them would be soon gone as well. All life depends on a constant source of energy. As illustrated in the figure below, only autotrophs can convert the ultimate solar energy source into the food chain that fuels life.

Similarities between Heterotrophs and Autotrophs

Photosynthesis is responsible for more than 99% of the energy required for life on Earth. A smaller number of autotrophs, mostly bacteria that live in
low-oxygen or dark environments make food with the chemical energy stored in organic molecules, such as ammonia, hydrogen sulfide or methane.

As photosynthesis converts the energy of light into the chemical form, this alternative method of food production transfers chemical energy from inorganic into organic molecules. It’s also known as Chemosynthesis and is a characteristic of the tubeworms depicted in the figure in the following.

A few recently discovered chemosynthetic bacteria live in the deep sea heated waters vents, or “black smokers.” There they make use of the energy of gases that come from the Earth’s innermost regions to make food for various distinct heterotrophs like enormous tube worms, blind shrimp and giant white crabs, along with armoured snails. 

Scientists believe that Chemosynthesis might be able to support life beneath on the surfaces of Mars and Jupiter’s moon Europa, as well as other planets too. Ecosystems built on Chemosynthesis could seem unusual and unattainable however they also illustrate the complete dependence of heterotrophs and autotrophs to feed.

Difference between Heterotrophs and Autotrophs

A food chain shows how energy and matter flow from producers to consumers. Matter is recycled, but energy must keep flowing into the system. Image Source:

Flow of Energy

The flow of energy through living organisms starts with photosynthesis. The process stores energy generated by sunlight by forming chemical bonds in glucose. Through breaking the chemical bonds in glucose cells, cells release stored energy and create the ATP they require. The process through which glucose is broken down and ATP is created is cell respiration.

Photosynthesis and cellular respiration seem similar to two different sides on the same coin. This is evident from the figure below. The product of one process is the reactions that are the products of another. Together, these two processes can store and release energy from living organisms. These two processes also cooperate to recycle oxygen within the atmosphere of Earth.

Difference between Heterotrophs and Autotrophs

This diagram compares and contrasts photosynthesis and cellular respiration. It also shows how the two processes are related. Image Source:


Photosynthesis is thought to be the most important process that life has on Earth. It transforms the energy of light into chemical energy and releases oxygen. Without photosynthesis, there’d not be oxygen in the air. Photosynthesis requires a myriad of chemical reactions. However, they can be put together into an equation that is a single chemical formula:

6CO2 + 6H2O + Light Energy → C6H12O6 + 6O2.

Photosynthetic autotrophs take in the sunlight’s light energy and absorb carbon dioxide and liquid water from their surroundings. Using light energy, they mix the reactants to create glucose and oxygen, an unneeded product. The glucose is stored mostly as starch, then release oxygen to the atmosphere.

Cellular Respiration

The process of cell respiration “burns” glucose for energy. But it doesn’t generate the same intense or light heat, unlike other types of burning produce. This is because it releases energy from glucose slowly and in smaller steps. The energy is released to make the molecules that makeup ATP. Cellular respiration has many chemical reactions that can be summarized with the following chemical equation:

C6H12O6 + 6O2 → 6CO2 + 6H2O + Chemical Energy (in ATP)

Cellular respiration takes place in cells in all living creatures. It occurs in cells of autotrophs as well as heterotrophs. They all burn glucose to create ATP.

Take Away

Autotrophs store energy from chemical reactions within carbohydrates, making them into food molecules themselves. Autotrophs typically make their “food” through photosynthesis using the energy from the sun. Heterotrophs can’t create the food they consume, so they have to eat or take it in. Chemosynthesis is a method of making food products using the chemical energy stored in organic molecules.

Further Readings

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