Ecosystem: Definition, Components, and Structure

Ecosystems are a fundamental part of biology that help us understand how communities in nature  function and interact with their environments. Ecosystems are also complex and multilayered, with  many interconnected parts.  

👉 So what is an ecosystem? What components are ecosystems comprised of and how are they structured?

A good way to remember how to define an ecosystem is to break down the word itself into “eco” and  “system”.

“Eco” is short for ecology, which is how living beings interact with each other and their non living environment. If you mesh that definition with “system”, you get a new biological discipline that  looks at these relationships as cogs in an interconnected network.

Ecosystem Biomes

Many ecosystems together form biomes. Biomes are a collection of alike ecosystems that form larger regions, such as forest ecosystems, grassland ecosystems, desert ecosystems, or aquatic ecosystems.  

Some ecosystems are interconnected with other nearby ecosystems in the same biome. Others, however, are either fractured or isolated.  

Island biogeography

When we build highways that cut right through the a terrestrial ecosystem such as a forest, we are fracturing an ecosystem into separate parts, limiting the flow of energy from one side to the other. Animals will still try to cross, however, and  unfortunately can end up as roadkill.

When an ecosystem is separated from all other ecosystems of a similar type, it follows an interesting  pattern based on island biogeography.  

Island biogeography tells us that when an ecosystem is isolated, it experiences rapid speciation – creation of unique living organisms. Lakes on the side of a mountain, oases in the desert, islands in the middle of the ocean, and caves are all examples of island ecology.

When it comes to the survival of humans, ecosystems provide many ecosystem services – benefits that  humans receive from ecosystems. They are also a lens that can help people understand the importance  of the environment.  

For example, among other ecosystem services, humans receive:

• Food
• Clean air and water
• Regulated climate
• Healthy soil
• Resources for buildings and clothing‍

However, if we do not treat our ecosystems with respect, we could either lose the quality of some of  the ecosystem services or a service all together.  

For example, consider if a forest were clear cut to build a housing development. The air quality of that  area would be lower than the surrounding environment since it would have significantly fewer trees to filter the air. It's the same reason why air smells and feels fresher in the forest than it does deep in a city – there is a higher oxygen content in the forest, exactly what our bodies prefer.  

We can split ecosystem components into two parts – biotic and abiotic components (ie. living and non living components).

Biotic factors

Examples of biotic factors include:

• Trees
• Animals
• Fungi
• Grasses
• Bacteria
• Humans

Abiotic factors

All of the above living beings rely on abiotic factors for life, they include environmental factors such as:

• Water
• Sunlight
• Minerals in the soil
• Landscape
• Temperature
• Humidity

How are biotic and abiotic components linked together?

These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the system through photosynthesis and is incorporated into plant tissue.

‍👉 Did you know? Ecosystem ecology is the study of living (biotic) and non-living (abiotic) components of ecosystems and their interactions within an ecosystem (ie. ecosystem processes).

A change in just one factor can have varying and profound effects on the others. For example, with global warming, some ecosystems will experience a significant change in temperature that will make that space uninhabitable for some of its plants and animals.

Like our earlier example, if a forest is clear cut, the lack of trees drastically alters the forest ecosystem. The  animals lose their habitat, plants that were shaded out now flourish, and the humidity, temperature,  and even weather patterns of that area will change.

What makes an ecosystem strong is its resilience. This is where biodiversity comes into play – biodiversity is important because it is the safety net of an ecosystem.  

Species richness is a term used to describe the number of species in an ecosystem, which is often  correlated with its health. High species richness is many species living in an area and indicates a healthy  and resilient ecosystem. It is common in a tropical rainforest where it tends to be hot and wet, as we will  discuss more later.  

Ecosystem, structure 

Producer, consumer and decomposer

Essential to ecosystem structure is the flow of energy and nutrients that keep ecosystems alive and healthy.  

The various life cycles, like carbon, water, and nitrogen, are key processes in making Earth a habitable planet. And on Earth, ecosystems are the building blocks.

⚠️ Each species plays a role in these cycles of energy, and can be characterised as a producer, consumer, or decomposer.

Producers, like trees and grasses, have a name that beguiles their powers. They consume several abiotic (non-living) components – sunlight, carbon in the air, water, and nutrients in the soil – to create new growth via photosynthesis.  

But producers were named for how they contribute to their ecosystems. Their miraculous alteration of  energy is exploited by consumers, like animals and insects. Consumers, as their name suggests, consume  producers or other consumers for energy.  

Decomposers, like fungi and bacteria, get their energy from consuming dead producers and consumers.  They are essential to the functioning of ecosystems – their efforts are what make fertile soil that creates  healthier producers, which make healthier consumers, and so on.  

Ecosystem structure example

As an example of ecosystem structure, we will look at one specific  species and how it interacts with its environment.

A peregrine falcon that lives in the state of New Hampshire survives there because it can find food and water and has a coat that is suitable to the climate there. However, the falcon will migrate to Ecuador  during the winter because it cannot survive the freezing temperatures of New England.  

The peregrine falcon has a diet of rodents and smaller birds. A songbird that the falcon may eat has a  diet of worms, seeds, and berries. The worms help decompose dead matter, making the soil more  nutritious for the plants that grew the seeds and berries. As we know, the plants rely on rainwater,  sunlight, and carbon dioxide in the atmosphere to photosynthesise.

Due to these biotic and abiotic factors that work in harmony, the peregrine falcon can flourish in its  ecosystem.

Aquatic ecosystems

Within the aquatic ecosystem category, there are both freshwater and marine ecosystems (also known as ocean ecosystems). Freshwater ecosystems include rivers, ponds, lakes, and springs, while a marine ecosystem encompasses the various parts of the ocean.

Marine areas can be specified down to the following different types of ecosystems:

• Shallow ocean like coral reefs.
• Deep ocean where some light is present.
• Deep ocean bottom where often there is no light.  

Terrestrial ecosystems

Like aquatic ecosystems, terrestrial ecosystems vary depending on climate and geography. They comprise forest ecosystems such as tropical forest, temperate forest, of boreal forest.

Terrestrial ecosystems also include grassland ecosystems, shrub land, mountain areas, tundra, and desert ecosystems.

👉 Did you know? Of all types of ecosystems, tropical rainforests have the most biodiversity.

Why tropical rainforests, you might ask? Well, they have very stable climates that promote growth.  Tropical rainforests, being close to the equator, usually do not experience seasons or significant changes in climate between months. They tend to be very wet and warm, both good indicators for where to find an abundance of living organisms.  

Because of this stability, tropical rainforests have massive trees that create more ecosystem levels  within themselves. There are canopy ecosystems that are unique to the top of the trees as well as understory ecosystems that do not see direct sunlight.  

Both canopy and understory ecosystems, despite being very close to each other, are home to quite different species. For example, monkeys have learned to thrive in canopies because of their ability to  swing from branches, keeping them safe from predators on the ground. Whereas certain plants will only thrive in the understory because they have developed shade tolerance to survive.

Unfortunately, ecosystems across the world are facing significant changes due to human-induced climate change. Our fossil fuel emissions are contributing to global environmental destruction. They will  continue to do so unless we limit our emissions and work to remove our excess of greenhouse gasses  from the atmosphere.

If you contact Greenly, you will be taking a step to improve the health of global ecosystems. We can  perform a life cycle analysis of the product of your business to help you understand your environmental  impacts. We also can set you up with verified and reliable carbon offset projects.