Heterotrophs are organisms that obtain their energy (nutrition) from organic compounds/materials.
In other words, heterotrophs are organisms that are unable to produce their own food (like autotrophs) and therefore have to ingest organic compounds as a source of energy.
Hearing that, you might know one or two organisms that fit that label – yourself included! Yes, heterotrophs include a wide array of organisms, including human beings and mammals.
You may never have heard the term before, but you’re included in it – how cool is that?
If you want to learn everything about heterotrophs and the types of nutrition, just keep reading! We’re going to be going through everything you could possibly want to know right here. Interested? Let’s get started.
Here, we’re going to go through what heterotrophs are. After that, we will be exploring the various types of nutrition available. Stick around to be amazed.
What Are They?
So, heterotrophs are organisms that get their energy from organic materials. They are creatures that are unable to produce their own food like autotrophs can.
Because of this, they are required to ingest organic materials or compounds as their only source of energy.
We will go through the differences between heterotrophs and autotrophs at the end of this post. However, in simple terms, autotrophs are organisms that are at the bottom of the food triangle.
They are able to make their own food using a different means entirely.
Heterotrophs you might be familiar with include things such as:
- Dragon flies
- Plasmodium species (malaria parasites)
Types Of Nutrition
Many people probably don’t think about nutrition too much. However, there are a lot of interesting points to talk about when it comes to nutrition.
As heterotrophs, we all require food or organic material to provide us with energy and nutrients. Nutrition isn’t that straightforward, though – there are three primary kinds of nutrition!
These three primary types of nutrition are as follows:
- Saprotrophic nutrition
- Holozoic nutrition
- Parasitic nutrition
We’ll be going through each of these types of nutrition in detail below. By the end of this post, you’ll know everything you need to know about them all!
Saprotrophic nutrition is the name given to the nutrition that involves the absorption (consumption) of food or organic material from decaying plants or animals.
Any organism that is known to obtain their required nutrition from decaying plants or animals are known as saprophytes or saprotrophs.
A number of bacteria and fungi are included in this, as well as many more organisms that are similar to fungi – for example, water molds.
Organic matter for saprophytes gets broken down into a more simple substance thanks to the enzymes present. Once the organic matter has been broken down, it then gets absorbed by the organisms and is turned into a nutritional energy source.
Although a great many saprophytes such as fungi possess a number of plant-like traits, it’s important to note that they are not plants.
These organisms are not able to produce their own food, meaning that they have to ingest organic matter to get energy. As such, they are heterotrophs.
Understanding Saprophytic Fungi
This includes things like yeast and mucor. The term “sapro” means !decaying material”, which explains everything about these organisms.
Mucor is a type of saprophytic fungi that cannot make their own food or even ingest food like higher animals are able to. They require a completely different mechanism in order to get the nutrition that they need to survive.
Simply put, the body of mucor is divided into threads, which are known as hyphae. The hyphae grow and spread through the organic matter that the organism is growing on.
This can be anything from bread to plants to rotting animals. Through the hyphae, the nutrients are absorbed, and the organism gets everything it needs.
The presence of digestive enzymes such as oxidases and cellulases allow the substances to be brown into simple molecules. These simple molecules are then absorbed via diffusion by the fungi.
Yeast, on the other hand, is also classed as fungi. However, yeast is actually a single celled organism which produces spores when it reproduces. These fungi cannot produce threats or hyphae like mucor, so they get the nutrients they need another way.
This method of gaining nutrition is called “extracellular digestion”. When this occurs, yeast produces and releases a digestive enzyme into their environment.
The enzyme helps break down the organic material in the area into simple molecules and nutrients. Once this happens, the nutrients are then taken to the cell by the organism to nourish it.
Anyone who learned about fungi in life will know that they need four simple things in order to thrive and survive. These four things are as follows:
- Neutral or slightly acidic pH
Without these four basic needs being met, saprophytes would not be able to thrive.
Why Saprophytic Fungi Are Important?
Now, you might be wondering why these fungi are important – why bother talking about them? Well, these fungi actually play an incredibly important role in nature and life.
These organisms aid in the breakdown of dead matter by turning it into a simple substance. In other words, dead plants and animals are broken down in order for new growth to occur and new organisms to thrive.
Some of these fungi can be food, such as mushrooms, while others are poisonous. When it comes to things like yeast, it is incredibly important because it plays a role in fermentation.
Fermentation in turn is an important part of baking and even the process of making alcohol!
There are saprophytic bacteria as well as fungi. These bacteria are typically found on decaying matter, such as rotting plants or animals. This includes things like rotting wood or even matter found in water that is stagnant.
Much like other saprophytes, this type of bacteria is able to produce digestive enzymes to break down matter.
A few examples of saprophytic bacteria are as follows:
- Clostridium thermosaccharolyticium
- Clostridium aceto-butylicum
Like saprophytic fungi, this type of bacteria is also incredibly important in the natural world. These bacteria play the biggest role in decomposing organic matter.
However, they also have other important roles in breaking down various waste materials that we have to deal with. These include:
- Spoiled food – saprophytic bacteria are known to speed up the rate at which food spoils, and also break down that same food. Because of this, they can be a nuisance to deal with, but are important nonetheless.
- Manure – since these bacteria have a role in breaking down organic matter, they are frequently used in farms to help break down dung, or complex organic material. This is turned into mature, which then gets used to promote plant growth.
- Fermentation – these bacteria are also used in fermenting, as well as aiding in the production of vinegar, among many other things.
The word holozoic is made up of two words from the Greek language – “holos” – meaning “whole”, and “zoic” – meaning “animal”. As such, you can literally translate this form of nutrition as “whole animal”.
This is a very different form of nutrition compared to saprophytic. Unlike in saprophytic nutrition where organisms absorb nutrients, holozoic nutrition refers to the fact that organic matter must be ingested by the organism.
As such, holozoic organisms must consume solid (or liquid) food in order to get the nutrients they need. This food is then broken down inside the organism themselves, and relayed to the cells within the organism.
We as humans fall into this category! As do most of the animals and creatures we will come across in our daily lives.
What Creatures Come Under This Term?
- Single celled organisms (e.g. amoeba)
There Are Three Groups Of Holozoic Organisms:
Let’s take a look at these three categories below to get a better understanding of what they actually mean.
Omnivores are animals that are able to eat both animals and plants. Being an omnivore (like humans) is a trait that is typically seen as beneficial, as it can make living in various environments easier.
Some environments have small amounts of plant matter and meat, which means that omnivores would thrive, since they wouldn’t have to depend on one or the other.
Humans are omnivores. As are creatures such as brown bears, dogs, raccoons, and even a number of bird and insect species.
If you took a look in your own mouth, you are likely to see that you have canines (the sharper teeth) on either side, as well as molars.
Carnivores are organisms that typically hunt (or scavenge) other animals and eat their meat. They only eat meat, and are typically capable hunters, though this might not always be the case.
Carnivores are only able to get the nutrients they require by eating meat. While these animals are able to ingest plant matter, they will not benefit from the nutrients found in plants or other organic materials other than meat.
Depending on where a carnivore is on the food chain, they may only be able to eat herbivores. Other carnivores might be able to eat both herbivores and omnivores.
Some carnivores might be able to eat other carnivores on top of herbivores and omnivores. An example of a carnivore that can eat other carnivores would be hyenas – as they often eat lion cubs.
Since carnivores need to hunt, they typically need a lot of energy in order to do so. Protein, which comes from meat, is a great source of energy. These animals typically have a set of characteristics that set them apart from their herbivore counterparts.
For example, they are likely to have long, sharp canines, talons, and sometimes even poisons. Just think about eagles, sharks, and lions – they all have sharp, pointy features (talons, teeth, claws, etc.) to help them catch prey and easily eat it.
Herbivores are animals that only consume plants in order to get energy and nutrients. These animals can have all kinds of different diets, depending on the animal and their location.
Some herbivores might only eat certain parts of plants, such as the bark, while others will only eat the leaves or fruit. As such, herbivores are not all able to eat all types of plants.
A great example of this would be to compare giraffes to animals such as cows – the giraffe is able to eat leaves of the acacia tree, which has thorns.
Because of its long tongue, the animal is able to separate the leaves from thorns safely. On the other hand, a cow would be unable to do this, and would predominantly eat grass because of its anatomy.
Herbivores all have different unique anatomy. Goats can eat and digest the bark of trees thanks to their hard upper gum and strong lower teeth combined with their unique intestines.
This would be a trait that few other herbivores have, hence why they eat other plant matter.
- Browsers – animals that are browsers will usually feed on things like shrubs, soft shoots, fruit, and leaves. There are many browning animals, including wild goats, black rhinos, and deer.
- Grazers – animals that are grazers will usually eat grass. These kinds of animals include things like cows, kangaroos, and white rhinos.
- Intermediate feeders – these are animals that can both graze and browse. A good example of these animals include sheep. You will notice that these animals tend to have larger rumen and narrow muzzles, which allow them to do this. Many animals fall into this category.
Parasites are likely everyone’s least favorite type of organism. When we’re talking about a parasite model of nutrition, we are referring to a type of nutrition where an organism is dependent on a host (another organism) for their nutrition.
The organism that we call the parasite is the one that depends on another living thing for the nutrition that they require – think of ticks.
The host, or living thing that the parasite is relying on, is the one in the pairing that does not benefit from the relationship. In fact, in some cases, the host can actually experience negative side effects because of the relationship.
There are a number of parasites that we live alongside in our everyday life and cause horrific issues.
Common examples of different parasites include:
- Bed bugs
- Mosquitoes and malaria parasites
Every single one of the parasites mentioned above are likely to be ones that you are already familiar with. Ticks are a very common issue in the country, and can cause horrible sickness and even death in animals and humans.
Similarly, many mosquito species are known for spreading malaria, another deadly disease that kills millions.
Parasites can be animals as well as plants. In most cases, they can have dire consequences and even cause death if issues are left untreated. Anyone with pets or livestock is likely to know how important checking for parasites can be in their animals.
Two Types Of Parasites
There are two types of parasites that you can experience. These are either total or partial parasites. Let’s take a look at both of them below:
These are parasites that are fully dependent on their host. They need the host for not only shelter, but also food and water. Endo-parasites include things such as malaria parasites and tapeworms.
In other words, these types of parasites are parasites that physically live inside the host, and would not be able to survive if they found themselves outside the host.
In the plant world, Cuscuta is a parasite that is reliant on plants like Zizyphus in order to survive.
As the name suggests, partial parasites are parasites that only partially depend on a host, usually for things like food. An example of this would be the mosquito (specifically, the female mosquito).
The female mosquito is reliant on organisms to get blood for their food, but they otherwise do not need a host in order to survive. In the plant world, Viscum is a good example of a partial parasite, and it can often be found on Oak tree branches.
Understanding The Difference Between Heterotrophs And Autotrophs
As we briefly mentioned earlier, there are some key differences between heterotrophs and autotrophs. The first cannot make their own food, while the latter can.
Autotrophs can make their own food by using carbon dioxide and sunlight, so the sunlight is their source of energy.
In other words, plants are a type of autotroph. However, not all autotrophs are plants. There are two types of autotrophs – photoautotrophs, and chemoautotrophs.
Photoautotrophs use light to create energy. This is called photosynthesis. On the other hand, chemoautotrophs have the ability to turn chemicals into energy. This process is called chemosynthesis.
Autotrophs have chlorophyll, which is found in both plants and bacteria. They can use this chlorophyll to trap energy in the world of light and use it in order to make food.
Because autotrophs are able to create their own food from something like light, they are actually one of the most important elements in the whole food chain.
They do not rely on other organisms to feed them nutrients, though they do help. Instead, they can feed themselves and give themselves what they need in order to thrive and grow.
As such, autotrophs are actually the most important part of the whole ecosystem. They are the primary producers of the world, and make up the ecosystem’s foundation. Nothing else has the ability to do that.
Heterotrophs, while you may never have heard a lot about them, make up a massive percentage of the world’s organisms. They include beings like humans, dogs, cats, frogs, insects, and most other things you can think of.
However, these creatures all rely on various types of nutrition to keep them alive. We as humans may not give nutrition types a lot of thought in everyday life, but it is a pivotal part of our existence.
From saprotrophic nutrition, to holozoic and parasitic, when you look around you, you will notice that these things occur every day.
Hopefully this has been helpful, and you now understand heterotrophs and nutrition a little more now. Keep learning, you never know what you will find out next!
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