Difference between autotrophic and heterotrophic organisms with examples

Organisms are also called producers , since they have the ability to produce their own food from inorganic molecules and a source of energy. Most autotrophic organisms are plants. Autotrophic organisms are classified into two classes :

• Phototrophs: These organisms synthesize organic molecules using sunlight for energy and as precursors to carbon dioxide and water. This synthesis process is called photosynthesis and the organisms that carry it out usually have the pigment chlorophyll. Most plants, algae, some bacteria and phytoplankton belong to this category.
• Chemotrophs or chemosynthetics: these organisms obtain their energy and organic molecules from chemical reactions between inorganic molecules. Some bacteria that live in extreme conditions belong to this category.

Some clear examples of autotrophic organisms are:

Plants

Plants are usually photoautotrophic organisms, with very few exceptions (such as carnivorous plants , such as the Venus flytrap that feeds on flies). Thanks to chlorophyll, it captures photons of light and produces sugars and other substances for its food. Plants are usually consumed by heterotrophic animals that use these organic substances.

Green algae

Green algae , such as verdigris or some marine algae, are photoautotrophic organisms. In fact, green algae come from ancient cyanobacteria, a type of green algae that began the process of turning Earth into a planet with an oxygen-rich atmosphere.

Iron bacteria

These organisms are chemoautotrophs. An example is the bacterium Acidithiobacillus ferrooxidans , which obtains energy from ferrous iron, transforming it from an insoluble to a soluble form. These types of organisms have their applications in biohydrometallurgy and mineral extraction that cannot be extracted by conventional means.

Heterotrophic organisms are also called consumers , since they obtain energy for their metabolic activities from the consumption of plants and producer organisms.

These types of organisms are unable to produce their own food and require autotrophic organisms, both directly and indirectly, for their survival. The categories into which heterotrophic organisms are classified are more varied than that of autotrophs.

There are many more categories in heterotrophic organisms than in autotrophs. Some examples of heterotrophic organisms are:

Herbivores

These organisms feed on plants, which is why they are also called primary consumers. Through this diet, they obtain, among other molecules, complex carbohydrates such as starch or cellulose. Starch is easily broken down (most animals have amylase), but cellulose (a component of plant cell walls) requires a special enzyme, cellulase, which is found specifically in the intestines of herbivorous animals or by organisms. symbiotic intestines.

Examples of herbivorous animals are cows, deer, sheep, and other ruminants or elephants. Those that feed on fruits or frugivores such as birds, bats or monkeys are also considered herbivores.

Carnivores

They feed on primary or herbivore consumers, or other carnivores, which is why they are also called secondary and tertiary consumers. The energy they obtain is that which flows throughout the entire food chain, starting with autotrophic organisms. This energy is used to make its biomolecules or is stored.

Examples of carnivorous organisms are the lion, snakes or sharks. Scavengers such as vultures or cockroaches are also carnivores , since they consume meat from dead animals.

Decomposers

They feed on dead organic matter through decomposition and absorption . These substrates on which they feed can be very diverse, such as wood, cheese, meat or litter. Examples of decomposing organisms are some fungi or small invertebrates. The decomposers play an important role in the trophic cycles of ecosystems, because they act allowing the recycling of nutrients within ecosystems . In addition, they are important for humans economically and for food, because thanks to them we can produce certain foods that we consume.

As a summary, you can see 3 differences between autotrophic and heterotrophic organisms that are fundamental:

• Autotrophic organisms make their own food through photosynthesis or chemosynthesis, while heterotrophs depend on autotrophic organisms for food and use energy for metabolism.
• Most autotrophs use the pigment chlorophyll, while heterotrophs do not have chlorophyll.
• Autotrophic organisms depend directly on sunlight, while heterotrophs indirectly.

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