Chemoheterotroph Definition

You are a chemoheterotroph, which may come as a surprise to you.

The word “chemoheterotroph” refers to a creature that gets its energy from chemicals, but has to eat other species to survive. That includes you; your body obtains its energy from food, and in order to exist, you must eat other species such as plants and animals.

In order to exist, all creatures must overcome two problems: they must be able to receive energy and cellular “building materials” like proteins, lipids, and carbohydrates.

The majority of organisms that ingest organic matter use it as both an energy source and a source of construction materials. Animals and fungi, for example, gain energy and building components for their own cells by breaking down the food we consume.

However, a few rare species utilise inorganic molecules for energy, but are unable to produce their own building elements. To live, these creatures—almost typically bacteria—need both inorganic chemical energy sources and other species that can provide them with organic resources.

Chemoheterotrophs are found in all mammals. Fungi are similar to plants in appearance, but they do not undergo photosynthesis and instead get their energy by breaking down organic matter in the soil.

Many bacteria that dwell within the human body, as well as many pathogenic bacteria and certain sulphur bacteria, are chemoheterotrophs.

Functions of chemoheterotrophs

Chemoheterotrophs serve an important function in the majority of ecosystems.

While “producers” at the bottom of an ecosystem’s energy pyramid create energy and organic materials from scratch, chemoheterotrophs feed on those producers at the top of the pyramid. Chemoheterotrophs include herbivores, predators, scavengers, and decomposers.

Chemoheterotrophs recycle resources from plants and chemoautotrophs in a complex web of life where components are reused again.

Types of Chemoheterotrophs

Chemoorganoheterotrophs—Eaters of Living Things

It’s a mouthful to say “chemoorganoheterotroph.” However, we’ve already learned what the terms “chemotroph” and “chemoheterotroph” mean.

“Chemoorganoheterotroph” simply adds “organo,” which refers to “organic” compounds. Organic molecules are carbon-containing molecules that are often linked with life, such as proteins, lipids, carbohydrates, and so on.

Chemoorganoheterotrophs are organic molecule feeders, but where do you go for organic molecules? Within living or dead creatures

Herbivores, carnivores, scavengers, and decomposers are all chemoorganoheterotrophs. All fungi and animals are included.

Chemolithoheterotrophs—Stone Eaters

“Litho” is the Greek root word for “stone,” just as “organo” is the Greek root word for “organic stuff.”

Chemolithoheterotrophs get their energy from inorganic minerals or other geological processes. Elemental sulphur and elemental gas are possible food sources for chemolithotrophs.

Bacteria are the most common chemolithoheterotrophs. Because obtaining energy from inorganic minerals is less effective than digesting sugars via cellular respiration, organisms that rely on this source of energy are often tiny and simple.

Chemolithoheterotrophs may be found on the seafloor or in subterranean water sources, where they can find both chemical and organic food sources.

They may derive their organic compounds by feeding on other bacteria or dead material from other creatures that collect on sea bottoms and river beds.

Examples of Chemoheterotrophs

Humans

It’s simple to see why people are chemoheterotrophs! Every day, we consume food. Animals, plants, and other species are used to make that food. We use the organic substances released by their cells to generate energy and manufacture materials for our own bodies.

Mushrooms

Mushrooms and other fungi may seem to be plants, yet they are more closely related to animals than plants.

Fungi get their energy by decomposing organic matter. It’s usually biological material that has already died or isn’t well-defended by the immune system of its host.

Mushrooms typically grow in rich soil, which is rendered rich by the decomposition of the carcasses of dead plants and animals, as well as on dead trees, old fruits, and other organic materials that lack an immune system to resist the fungus.

Some fungi may even assault and infect live mammals, despite their immune responses, but this is uncommon. For example, the Ophiocordyceps fungus attacks and digests live insects. Fungi may attack healthy people and cause serious illnesses only very infrequently—generally in patients with weakened immune systems.

Lithotrophic Bacteria

About all, chemolithotrophs are autotrophs, meaning they don’t need to eat other animals to thrive.

Similarly, almost all heterotrophs are organochemotrophs, meaning they get their energy and organic chemicals from the same place.

However, a few bacteria species that get their energy from minerals have gained the capacity to utilise organic molecules generated by other organisms rather than their own.

Some may have lost the capacity to produce organic materials on their own, requiring the presence of other species in addition to their mineral energy source to live.

Related Biology Term

• Any creature that gets its energy from chemicals is called a chemotroph. Chemoautotrophs, such as sulphur bacteria, and chemoheterotrophs, such as mammals and fungus, are examples of this.
• An energy pyramid is a graphic that depicts the transfer of energy via several sorts of creatures within an ecosystem.
• Heterotroph—Any organism that relies on the consumption of other species to live. Animals, fungus, and microbes all fall within this category.

Quiz

1. Which of the following root words is NOT found in “chemoheterotroph?”

1. “Chemo” for “chemical”
2. “Hetero” for “other”
3. “Troph” for “food” or “to eat”
4. “Auto” for “self”

Answer to Question #1

D is correct. The term “chemohetetrotroph” contains terms explaining that these organisms get their energy and building materials from chemicals, and that they rely on other organisms to provide these chemicals.

“Auto” is a root word found in descriptions of organisms that do NOT rely on others for energy or building materials.

2. Which of the following is NOT true of chemolithoheterotrophstrophs:

1. They derive their energy from inorganic chemicals.
2. They rely on other organisms for organic materials.
3. They solve the problems of obtaining energy and organic materials separately.
4. They obtain their energy and organic materials from the same source.

Answer to Question #2

D is correct. While most chemoheterotrophs obtain their energy and organic materials from the same source, chemolithotrophs need one source of inorganic chemicals to obtain energy and a different source – other organisms – to obtain organic materials.

3 Which of the following is NOT an example of a chemoheterotroph?

1. A dog
2. A daisy
3. A sulfur bacteria that can’t make its own organic molecules.
4. A mushroom

Answer to Question #3

B is correct. While all the other items on this list are organisms that derive energy from chemical sources and which need to eat other organisms in order to survive, a daisy is a plant.

That means it can make both its own energy and its own organic materials using just carbon dioxide from the atmosphere and light from the Sun!