What is an ecosystem? The definition of an ecosystem, how it works, how humans affect it and why – find all these issues answered below.

Simple Ecosystem Definition

The simplest definition of an ecosystem is that it is a community or group of living organisms that live in and interact with each other in a specific environment.

For instance, tropical forests are ecosystems made up of living beings such as trees, plants, animals, insects and micro-organisms that are in constant interaction between themselves and that are affected by other physical (sun, temperature) or chemical (oxygen or nutrients) components.

Ecosystem Scientific Definition

An ecosystem is the basic unit of the field of the scientific study of nature. According to this discipline, an ecosystem is a physically defined environment, made up of two inseparable components:

  • The biotope (abiotic): a particular physical environment with specific physical characteristics such as the climate, temperature, humidity, concentration of nutrients or pH.
  • The biocenosis (biotic): a set of living organisms such as animals, plants or micro-organisms, that are in constant interaction and are, therefore, in a situation of interdependence.

The concept of < ecosystem > is possible at several scales of magnitude. From multicellular organisms such as insects animals or plants to lakes, mountain ranges or forests to the planet Earth as a whole.

What Is A Marine Ecosystem?

Together with freshwater ecosystems, marine ecosystems are also part of the broader category of aquatic ecosystems. Marine ecosystems cover more than 70% of the Earth’s surface and have a high salt content. Some examples of marine ecosystems are offshore systems like the ocean surface, the deep sea, pelagic oceans or the seafloor. But there are also nearshore systems like coral reefs, mangroves or seagrass meadows.
Marine ecosystems can too be characterized following the abiotic and biotic dimensions mentioned above. In this way, its biotic components are organisms and their species, predators, parasites, and competitors. On the contrary, the concentration of nutrients, the temperature, sunlight, turbulence, salinity and density are its abiotic components.

How Do Natural Ecosystems Work?

Natural ecosystems are “balanced” systems. This means the interactions between the different organisms that make up the ecosystem contribute to a certain stability. For example, in grassland ecosystems, herbivores consume grass, but also feed the soil with their droppings, which allows the grass to grow back and allows some sort of balance. Still, this doesn’t mean an ecosystem, even a healthy one, is static. In reality, ecosystems are constantly evolving as they are based on dynamic processes that are constantly changing.

For instance, biocenosis are living organisms that interact with their environment and constantly transform it. How? Because animals compact the soil, plants create humidity or regulate the temperature and bacteria help in the microscopic world by protecting all sorts of animals from diseases and helping in their digestion process. As well, an ecosystem also evolves due to external or unforeseen events. A climatic or natural phenomenon, for example, can lead to transformations in the environment. In this way, biocenosis the ecosystem’s living organisms to adapt to these new constraints, and change happens.

It’s also curious that although an ecosystem is always looking for stability, the ecosystem never perfectly succeeds at it. The various natural imbalances tend to offset each other permanently. Some ecosystems evolve very slowly while others can transform very quickly. Sometimes, in extreme cases, they can even disappear.

How Does Energy Flow In An Ecosystem?

According to the law of energy conservation, energy can neither be created nor destroyed. In fact, it can only be transformed or transferred from one form to another. But how does this work in an ecosystem? How does energy flow here? Let’s watch this video to better understand this phenomenon.

We’ve managed to control fire, practice agriculture, and build transportation vehicles. We’ve built factories, dams, solar panels and we’re constantly finding new ways of exploring space. Still, the human race’s thirst to use, modify and transform natural ecosystems seems endless. For instance, when we transform a plain to grow cereal fields, we’re significantly modifying that local ecosystem. Sometimes, we even end up completely changing it from its original foundations.

Today, human activities have such an impact on ecosystems that we now speak of the Anthropocene timeline. This is a period that defines the significant human impact of human activities on the Earth’s atmospheric, biospheric, geologic and hydrologic systems. This period in time also considers changes happening due to climate change events, which is also mainly caused by human activities. We can see all these changes everywhere. When trees are taken down in the Amazonian forest, the ecosystems change as species struggle to survive and the local humidity and the climate both change. As well, building a dam also changes the distribution of water and affects the species living along the river’s course.

An example often used about how human activities affect ecosystems is the US Yellowstone National Park. Here, as in other national parks, the U.S. Biological Survey decided to kill wolfs and other species as a predator control measure. The problem was that the disappearance of the wolf population affected all the ecosystem in the long run, even changing the course of the local river. The wolf was later reintroduced in the Park, around 70 years later, in an attempt to restore the balance of the ecosystem. Check out the whole story on this video:

Why Is Preserving Ecosystems Important?

Like all other living beings, humans are dependant on natural ecosystem services to survive. We need it to get the food we eat, the water we drink and to transform raw materials into our everyday products. So in order to keep our living conditions, it’s truly important that we preserve natural ecosystems.

For example, the agriculture that provides our food depends on the characteristics of a specific ecosystem. Cereals or vegetables grow only under certain conditions of temperature and humidity. They also need certain natural processes, such as pollination, to take place. If we change these characteristics too intensely, there is the risk that we aren’t able to produce what we produce today, or at least not in the same way. That’s why there are some agricultural techniques that understand and manage food production (such as agroforestry, permaculture or regenerative agriculture) that the wider impacts of using herbicides, pesticides, exhausting nearby water sources or betting on different types of trees that make ecosystems more resilient.

What Are The Ecosystem Services?

According to FAO, ecosystem services, worth USD $125 trillion, “make human life possible by, for instance, providing nutritious food and clean water, regulating disease and climate, supporting the pollination of crops and soil formation, and providing recreational, cultural and spiritual benefits.” 

For all these to be possible, Earth’s ecosystems like forest ecosystems, grassland ecosystems, aquatic ecosystems or agroecosystems need to properly function. But the fact is that some ecosystem services are currently under threat.

Ecosystem Services: Examples

Without ecosystem services, life on Earth as we know it wouldn’t exist. There are four main categories of ecosystem services:

Provisioning services refer to the products secured by ecosystems. These include:

• Water
• Food (including cattle and seafood)
• Pharmaceuticals, biochemicals, and industrial products
• Energy (sunlight, hydropower, biomass)
Regulating services are the ecosystem services that allow the regulation of ecosystem processes such as:
• Climate regulation (and carbon absorption and storage via the oceans, trees, soil)
• Waste decomposition (one of the most essential microbial process happening in soil)
• Crop pollination (performed by agents such as bees that contribute to the reproduction of flowering plants)
• Water and air purification and regulation
• Control of pests and diseases
Supporting and habitat services refer to the ability of ecosystems to give habitat for migratory species and to support the viability of gene-pools.This is possible thanks to:
• Primary reproduction
• Nutrient and seed dispersal
Cultural services are the benefits ecosystem services bring to humans. Examples of these are:
• Inspiration for intellectual (creativity), cultural (entertainment) and spiritual (why) purposes
   – Remember how it feels good to seeing and hearing wild birds
   – Animals, plants and even the funghi kingdom serve as inspiration in theaters, movies…
   – Many people go to natural sites when they want to be alone or reflect about life
• Recreational experiences such as outdoors activities or ecotourism
• Scientific discovery and optimization/efficiency by following examples of the natural world (biomimicry)


Learn more about ecosystem services, how natural resources are being overexploited, how the environment is being damaged and how to protect ecosystem services for the future generations:

How Do Humans Affect Ecosystems? The Human Impact On Ecosystems

Human activities are having a negative impact on ecosystems. In fact, according to the famous Millennium Ecosystems Assessment, at the beginning of the 20th century, human activities changed ecosystems more rapidly than ever before.

Humaking has been demanding for food, water, food, timber, and other materials like crazy. And all these demands have been highly contributing to deforestation (to grow more crops), the loss of natural pollination (bees are disappearing), water pollution (from animal excreta and pesticides to plastic), soil exploitation (due to intensive agriculture), overfishing and huge biodiversity loss. But why are humans affecting ecosystems this much?

Why Are Humans Affecting Ecosystems?

ecosystem services definition examples
There is no straight-forward answer to this question. But human activities have impacts that aren’t instantaneously noticed. This means the visual impact of these effects isn’t there most of the time. As well, the ecological capital is hard to measure.

For instance, transforming land to build a hotel will have specific costs (buying the land, construction materials, manpower) and the revenue can be predicted via estimation of occupancy rate, price per season… But there’s no precise way to quantify what’s the value of that park and those trees that will need to be taken down to build it. What is its value for the environment? And for the families that go there every day? There’s no exact way of answering this, although organizations such as the European Parliament are trying to shed light on this issue.

Apart from the need to use ecosystems services at a large scale to keep the economy rolling, there’s also another very discussed theory on this issue. It says that if an ecosystem service is common and belongs to no one in particular, humans will exploit it until they exhaust it. This theory where individuals pursue their individual interests is called the tragedy of the commons. Find more info about it in our sustainable development definition.

Ecosystems Expanded To Human Environments

Generally speaking, we need to have a more rational approach regarding how we’re transforming ecosystems. We need to rethink the processes by which we change, take, use and get disposed of natural resources. They need to become more efficient and circular so that ecosystems can be better preserved. Only by restoring a more harmonious and lasting cohabitation with natural habitats and their living population we’ll be able to benefit from the Earth services. These are especially important to humankind’s survival on what concerns:

  • Supply: water, food, materials, energy resources, pharmacopoeia…
  • Regulation: climate, water cycles, bio-ecological cycles, atmospheric stability (oxygen production) and geological…

Ecosystems And Corporate Social Responsibility

To try and restore the health of ecosystems and their balance, our consumption and extraction processes will need to become more efficient and circular. For this, it is crucial that companies develop sustainability and CSR strategies–  that they assess their impact and act upon it. Governments need to create better regulations to encourage companies to follow this path, while at the same time, find ways to measure and include the natural capital in the most famous way (not necessarily a good or fair one) of accessing progress: GDP.

  • Related: Consumers Want Companies That Care About Social And Environmental Issues
  • The European Union Is Mapping Its Ecosystems And Their Services (MAES)

  • The goal of these large assessments conducted by the EU is to evaluate and measure ecosystems and their services in order to support better decisions on complex public issues. More specifically, they address issues such as biodiversity, water, agriculture, forests, and regional planning – hoping to provide reliable data used for better planning and implementation of positive projects. The latest edition (5th) was published in 2018.

[Image credits to marine ecosystem on Shutterstock and African ecosystem on Shutterstock]