[Biology Class Notes] on Difference Between Autotrophs and Heterotrophs Pdf [2024]

The most essential aspect of living is food. No living species can exist without consuming food. This food is derived and eaten by living species in 2 different modes. We are about to look at these 2 modes of nutrition that living things obtain namely autotrophs and heterotrophs. Along with their definitions, we will also get a quick understanding of their characteristics and difference between autotrophs and heterotrophs with examples.

Difference between Autotrophs and Heterotrophs

The key difference between autotrophic and heterotrophic nutrition in their source of intake. Autotrophs can prepare their food on their own. But heterotrophs depend on other surrounding organisms to get their required food. It is no wonder to consider autotrophs as Producers and heterotrophs as Consumers. Henceforth, heterotrophs take the position of secondary or tertiary levels, while autotrophs are present at the primary level in the food chain.

One more contrasting feature between autotrophs and heterotrophs lies in their ability to store natural elements. Heterotrophs cannot store their energy as they spend enough in their routine activities, even while searching for food. But autotrophs are capable of storing both energy and light.

Green plants and algae fall under the category of autotrophs as they will prepare their food by themselves using sunlight, chlorophyll by the means of the chloroplast and photosynthesis (convert chemical energy into inorganic substances). Animals such as tigers, cows, etc. cannot make their foods and hence need other species to get their nutrition (mostly by killing and also by consuming plants like a herbivore). As an added-value, animals, i.e. heterotrophs can move from 1 place to another in their search for food. But autotrophs remain in 1 stable place.

The key difference in an autotroph vs heterotroph is in their capability to get their main source of living – food. All plants are autotrophs and many animals are heterotrophs, classifying them in the way they make or get their food daily.

Autotrophs

As we now know, autotrophs are species that are independent when it comes to food aspects. They prepare their own food with the help of water and carbon dioxide (CO₂). The term ‘autotroph’ was coined by Albert Bernhard Frank. Furthermore, autotrophs can also be divided as chemoautotrophs and photoautotrophs. Since the majority of the autotrophic mode of nutrition is from plants, they also possess the characteristic of converting carbohydrates either as fatty acids to get lipids or change it into sugars such as cellulose, sucrose, starch, etc.

Heterotrophs

From our previous understanding, heterotrophs are living organisms that cannot make food on their own and rely on other fellow species. Meaning, heterotrophs depend on autotrophs while autotrophs remain independent in getting their nutrition. The heterotrophic mode of nutrition is continually surviving based on the availability of external food sources. Similar to autotrophs, heterotrophs are also subdivided into 2 namely photoautotrophs and chemoheterotrophs. Animals, birds, non-green plants and even human beings are the best examples for heterotrophs.

Flow Chart of Autotrophs and Heterotrophs

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Autotrophs and Heterotrophs Key Points

The prime difference between autotrophs and heterotrophs lies in their source of getting nutrition (food).
In the comparison of their level of importance to the ecosystem, autotroph vs heterotroph both are equally beneficial to the natural flow of energy.
Autotrophs prepare their food on their own whereas heterotrophs depend on other species or autotrophs to get their nutrition.
Green plants are the classic example to autotrophs as they make their food and convert chemical energy into oxygen and other inorganic substances using chlorophyll, added by the process of photosynthesis.
Heterotrophs get their food either by killing other animals (carnivore), feed themselves from both plants and animals (omnivore) or consume only plants (herbivore).

Did You Know?

There are other organism groups present named mixotrophs, who can produce their own food but still consume other living things for their food.
Venus flytrap is one example of mixotrophs.
These plants combine the food-producing ability with a heterotrophic nutrition lifestyle.
Saprophytic nutrition is where organisms depend upon dead remains of organisms for food
Parasitic Nutrition is where the animals depend upon other animals for surviving, but they consume as being a host.
and if these parasites are present there in the body they are called endoparasites.
Examples of parasites are Tapeworms.

Autotrophic & Heterotrophic Nutrition:

Autotrophic nutrition is a mode of nutrition in which organisms prepare their own food using sunlight

Heterotrophic nutrition is a mode of nutrition in which the organisms depend upon other organisms for their food. These organisms do not produce food like autotrophs

Types of Autotrophs

There are two types of autotrophs known as Photoautotrophs and chemoautotrophs.

Photoautotrophs use sunlight to prepare their own food. Chlorophyll is present in autotrophic organisms. With the help of this, food is produced and stored. Algae, bacteria, cyanobacteria algae are examples of photoautotrophs. Photo means light and Auto means self and trophs means feeding. Hence, photoautotrophs means organisms that produce food through light.

Chemoautotrophs are organisms that obtain energy from Chemicals to prepare their own food. Examples of Chemoautotrophs are sulfur-oxidizing bacteria and nitrogen-fixing bacteria. Chemoautotrophs also need carbon dioxide along with Chemicals to produce food. Chemo means chemical, Auto means self and trophs means feeding. So, chemoautotrophs are organisms that produce food with the help of chemicals.

Questions Based on the Topic

What are autotrophs and give example.
What are heterotrophs and give an examp
le.
What are the types of autotrophs?
Differentiate between autotrophs and heterotrophs.
Do Autotrophs depend upon heterotrophs? If yes, explain why.
Are fungi Heterotrophs or autotrophs?
How do Autotrophs produce food?
How are chemoautotrophs different from photoautotrophs?