Ecosystems

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Ecosystems

An ecosystem is a system made up of a group of organisms, the habitat in which they live, and the relationships established between them.

The species of living beings that inhabit an ecosystem interact with each other and with the environment, determining the flows of energy and matter that occur in that environment.

On the planet, there is a great diversity of ecosystems, which are classified into different types: aquatic, terrestrial, mixed, microbial, artificial, and subterranean.

Currently, many ecosystems are at risk due to human activities. Pollution, overexploitation of resources, deforestation, and the effects of climate change often lead to extinctions, overpopulation, mutations, and displacement, which threaten biodiversity and the systemic balance of nature.

Characteristics of an Ecosystem

They are complex systems due to the interactions between their members. The greater the biodiversity, the greater the complexity of the ecosystem.

They are dynamic and variable environments, which experience natural or artificial changes and a constant flow of energy and nutrients between their constituent factors.

Their main source of energy comes from solar radiation. This energy is used by plants to convert inorganic matter into organic matter.

They can be altered naturally or by human action. Alterations caused by human activity can cause irreversible damage.

They are studied by ecology, the branch of biology that focuses on living beings and their relationship with the environment they inhabit.

Components of an ecosystem.

Biotic elements: These are the elements that support life, that is, all the living beings that inhabit an ecosystem. For example: animals and plants.

Abiotic elements: These are nonliving elements that are part of an ecosystem. For example: climatic conditions, terrain, pH variation, the presence of sunlight or water.

Types of Ecosystems

There are several types of ecosystems, which are classified according to the habitat in which they are located:

Aquatic ecosystems: These are characterized by the presence of water as their main component and are the most abundant type on the planet: they constitute almost 75% of all known ecosystems. This group includes ecosystems of the oceans and those of fresh or salt continental waters, such as rivers, lakes, and lagoons.

Terrestrial ecosystems: These occur on the Earth's crust and above water, in various types of relief: mountains, plains, valleys, and plains. There are significant differences in temperature, oxygen concentration, soil, and humidity between them, so the biodiversity of these ecosystems is large and varied. Some examples of this group are forests, scrublands, steppes, and deserts.

Mixed ecosystems: These are located where the aquatic and terrestrial environments combine, giving them a unique dynamic. The living beings that inhabit them (such as amphibians) spend most of their time in one of the two ecosystems, but require the other to rest, feed, or reproduce. Some examples of this group are mangroves, estuaries, and coasts.

Microbial ecosystems: They are made up of microscopic organisms that inhabit practically all environments, both aquatic and terrestrial, and even within larger organisms, as is the case of the intestinal microbial flora of humans.

Artificial ecosystems: They are created and/or intervened by humans, which is why they are also These are known as anthropogenic ecosystems, and they are increasingly common around the world. Some examples of this group are urban ecosystems, reservoirs, and agricultural ecosystems.

Underground ecosystems: These ecosystems are located beneath the Earth's surface and are inhabited by organisms adapted to conditions of darkness and limited resources. Examples of this group include caves and underground water systems.

Examples of ecosystems

Coral reefs: These ecosystems represent one of the largest concentrations of life in the underwater world and occur within and around the coral structures that form in the seas. Due to the abundance of organic matter that lives in them, numerous species of fish, crustaceans, and small mollusks also serve as food for predators.

Underwater abyssal zones: These are ecosystems located in the depths of the ocean, with little animal presence and no plant presence, since the absence of sunlight prevents photosynthesis. The organisms that live there adapt to the enormous water pressure, lack of light, and limited food.

Polar Zones: These are ecosystems characterized by very low temperatures and low atmospheric humidity. Despite this, they have a sea rich in plankton and fauna adapted to icy waters (the animals have hairy bodies and dense layers of fat, among other adaptations).

Water flows: These are ecosystems that occur within and on the margins of rivers, streams, or springs on the Earth's surface. Life in them adapts to the flow of water, which carries with it nutrients, chemicals, living species, and oxygen.

Forests: These are ecosystems made up of extensive and dense stands of tall, leafy trees with wide crowns, where animal and plant species abound. They are generally located in regions with warm and humid climates.

Deserts: These are ecosystems with extreme temperatures, little rainfall, and sparse vegetation. The organisms that inhabit them have developed adaptations to conserve water. Furthermore, animals often carry out their vital activities at night to avoid the heat of the day.

Savannas: These are grassland ecosystems with a few scattered trees. They have flora and fauna adapted to the lack of water. They are generally found in warm, dry regions of Africa and parts of South America.

Wetlands: These are ecosystems where water accumulates permanently on the surface. This allows for the development of a unique biodiversity, with vegetation adapted to saturated soils and a large number of amphibious animals.

Mountains: These are ecosystems that develop at high altitudes. As you ascend, the temperature drops, so vegetation and fauna must adapt to the cold, poorly developed soils, and steep slopes.

Food chains in ecosystems

Food chains are representations of the feeding relationships that exist between the species that make up an ecosystem. Generally, food chains interrelate, forming food webs.

A trophic relationship exists between two organisms when one is consumed by the other. In turn, the consuming organism can be the food of another organism that is part of the same ecosystem. Thus, a connection is created between several links, forming a food chain. Each link in a chain represents an organism that eats another or is eaten by another.

Within food chains, there are different trophic levels, which are based on the position each organism occupies in the flow of matter and energy. In other words, the trophic level groups all the species that share the source of their food within the ecosystem. There are three trophic levels:

Producers: These are autotrophic organisms, meaning they are capable of producing organic matter (their own food) from inorganic matter through photosynthesis or chemosynthesis. Producers are the first trophic level, meaning they constitute the first link in food chains. This group is represented by plants, algae, phytoplankton, and some bacteria.

Consumers: These are heterotrophic organisms, meaning they feed on other living beings to obtain the matter and energy they need. There are primary consumers (herbivorous organisms, meaning those that feed on producers) and secondary consumers (carnivorous organisms that feed on primary consumers). There are also tertiary consumers (carnivorous predators) and quaternary consumers (large predators), which feed on secondary and tertiary consumers, respectively.

Decomposers: These are organisms that feed on decomposing organic matter; that is, they obtain the matter and energy they need from the remains of other living beings. They are essential in nature, as they allow the recycling of nutrients. This group includes fungi, earthworms, and some bacteria that recycle organic matter.

Activity. Answer the following questions.

Remember to review the answers to the open-ended questions at the bottom of this page.

1. What factors make up an ecosystem?

2. What is the main source of energy in ecosystems?

3. Which of the following ecosystems is considered terrestrial?

4. What type of organism occupies the first link in a food chain?

5. What do food chains represent in an ecosystem?

Once you click this button, the questions will close and you will not be able to change your answer.

6. Define mixed ecosystems and give an example.

7. What role do decomposers play in an ecosystem?

8. What is the difference between primary and secondary consumers?

9. What do plants use solar energy for?

10. What are some problems that threaten ecosystems?

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Answers to questions:

6. These are ecosystems that combine aquatic and terrestrial environments. The living beings that live there spend most of their time in one of the two ecosystems, but require the other to rest, feed, or reproduce.

7. These are organisms that feed on decomposing organic matter; that is, they obtain the matter and energy they need from the remains of other living beings. They are essential in nature, as they allow the recycling of nutrients.

8. Primary consumers feed on producers (plants). Secondary consumers feed on primary consumers.

10. Pollution, overexploitation of resources, deforestation, the effects of climate change, and human activity.

1. Sposob, G. (2025, 13 marzo). Ecosistema - Qué es, tipos, características y componentes. Concepto. https://concepto.de/ecosistemas/

4. The Editors of Encyclopaedia Britannica. (2025a, marzo 28). Ecosystem | Definition, Components, Examples, Structure, & Facts. Encyclopedia Britannica. https://www.britannica.com/science/ecosystem