The ecosystems they are systems of living beings in a given space.
They consist of:
- Biocenosis. It is also called a biotic community. It is the set of organisms (living beings) that coexist in the same space of uniform conditions. It includes various species of both flora and fauna.
- Biotope. It is a specific area in which the environmental conditions are uniform. It is the vital space for the biocenosis.
Every ecosystem is highly complex because it includes a network of relationships between various species of organisms as well as those organisms with abiotic factors, such as light, wind or inert components of the soil.
Natural and artificial
- Natural ecosystems. They are those that develop without human intervention. They are much more varied than artificial ones and have been extensively classified. For instance: dry forest, polar desert, seabed.
- Artificial ecosystems. They are created by human action and did not previously exist in nature. For instance: reservoir, greenhouse, streams.
Types of natural ecosystems
- Marine. It was one of the first ecosystems, since life on our planet arose in the sea. It is more stable than freshwater or terrestrial ecosystems, due to slow temperature variations. Can be:
- Photic. When a marine ecosystem receives enough light it can contain plants capable of photosynthesis, which affects the rest of the ecosystem, since it is the organisms that are capable of creating organic matter from inorganic matter. In other words, they start the food chain. They are the ecosystems of beaches, coral reefs, river mouths, etc.
- Aphotic. There is not enough light for photosynthesis, so these ecosystems lack photosynthetic plants. There is little oxygen, low temperatures and high pressure. These ecosystems are found in the deep sea, in abyssal zones, in the oceanic trench and most of the seabed.
- Sweet water. They are the rivers and lakes.
- Lotics. Rivers, streams or springs. They are all those in which the water forms a unidirectional current, presenting a state of continuous physical change and a great variety of micro-habitats (spaces with heterogeneous conditions).
- Lentic. Lakes, lagoons, estuaries and swamps. They are bodies of water where there is no constant current.
Those where the biocenosis it develops in the ground or subsoil. The characteristics of these ecosystems depend on humidity, temperature, altitude (height with respect to sea level) and latitude (proximity to the Equator).
- Woods. They include rainforests, dry forests, temperate forests, boreal forests, and subtropical forests.
- Desert. They can be found in subtropical or tropical climates, but also in ice sheets.
- Shrubs. They have bushy plants. They can be shrub, xerophilous or moorland.
- Grasslands. Where herbs have a greater presence than shrubs and trees. They can be prairies, savannas or steppes.
- Tundra. Where mosses, lichens, herbs and smaller shrubs are found in greater numbers. They have a frozen subsoil.
They are those that, being floodable, can be considered terrestrial or aquatic.
Examples of natural ecosystems
- Stream (aquatic, sweet, lotic). A stream of water that flows continuously but with a lower flow than a river, so it can disappear in dry stations. They are not usually navigable, with the exception of those that have a low slope and a considerable flow. But in any case, only very small boats, such as canoes or rafts, can be used. Streams have areas called fords that are so shallow that they can be crossed on foot. Small fish, crustaceans and a multitude of insects and amphibians can live in them. The plants are mainly freshwater algae.
- Dry forest (terrestrial, forest). It is also called xerophilous, hiemisilva or dry forest. It is a wooded ecosystem of medium density. The rainy seasons are shorter than the dry seasons, so species less dependent on the availability of water develop, such as deciduous trees (they lose their leaves and therefore do not lose as much moisture). They are usually found between rainforests and deserts or savannas. Its temperatures are warm throughout the year. Monkeys, deer, cats, a variety of birds and rodents live in these forests.
- Sandy desert (desert land). The soil is mainly sand, which forms dunes by the action of the wind. Specific examples are:
- Kalahari desert. Despite being a desert, it is characterized by a variety of fauna, including rodents, antelopes, giraffes and lions.
- Sahara desert. The warmest desert. It has more than 9 million square kilometers of surface (an area similar to that of China or the United States), covering most of North Africa.
- Stony desert (desert land). Its soil is made of rock and stones. It is also called Hamada. There is sand but it does not form dunes, due to its small quantity. An example is the Draa desert in southern Morocco.
- Polar desert (desert land). The ground is ice. Rain is very scarce and the water is salty, so animals (such as polar bears) must obtain the necessary fluids from the very animals they eat. The temperatures are below zero degrees. This type of desert is called indlandsis.
- Sea bottom (aphotic marine). It is located in an area called “hadal”, which is below the abyssal zone, that is, it is the deepest in the ocean: more than 6,000 meters deep. Due to the total absence of light and high pressures, the available nutrients are very scarce. These ecosystems have not been sufficiently explored, so there are only unproven hypotheses about their inhabitants. It is considered that they survive thanks to marine snow, which is organic matter that falls in the form of particles from the most superficial layers of the ocean to the bottom.
- Great Sandy Desert. It is found in northwestern Australia. Among its fauna are camels, dingoes, goannas, lizards and birds.
- Marsh (hybrid). It is formed in a depression in the land bordering the sea. Usually this depression is formed by the passage of a river, so fresh and salt water mix in the area. It is a wetland, that is, an area of land that is frequently or permanently flooded. The land is naturally fertilized with silt, clay and sand. The only plants that can grow in this ecosystem are those that can withstand concentrations of salt in the water close to 10%. On the other hand, the fauna is very varied, from microscopic organisms such as benthos, nekton and plankton to mollusks, crustaceans, fish and rabbits.
- Continental platform (photic marine). The biotope of this ecosystem is the neritic zone, that is, the maritime zone that is near the coast but does not have direct contact with it. It is considered from 10 meters deep to 200 meters. The temperature remains stable in this ecosystem. Due to its great abundance of animals, it is the preferred area for fishing. The flora is also abundant and varied because the sunlight arrives with sufficient intensity to allow photosynthesis.
- Tropical meadow (terrestrial, grassland). The dominant vegetation are grasses, reeds and grasses. In each of these meadows there are more than 200 species of grasses. However, the most common is that only two or three species are dominant. Among the fauna are herbivores and birds.
- Siberian tundra (terrestrial tundra). It is located on the northern coast of Russia, in Western Siberia, on the shores of the Arctic Ocean. Due to the scarce sunlight that reaches this latitude, a tundra ecosystem developed, bordering on a fir and spruce forest.
Examples of artificial ecosystems
- Reservoir. When a hydroelectric plant is built, an artificial lake (reservoir) is usually created by closing the course of a river and thus making it overflow. The pre-existing ecosystems are profoundly modified since with the terrestrial ecosystems they become aquatic ecosystems when they are permanently flooded and part of the lotic ecosystem of the river becomes lentic ecosystem.
- Farmlands. Its biotope is fertile land. This is an ecosystem that has been created by man for 9,000 years. There are a variety of ecosystems, not only depending on the type of crop but also on the form of cultivation: whether or not fertilizers are used, whether agrochemicals are used, etc. The so-called organic gardens are fields of crops that do not use artificial chemicals but rather control the presence of insects through substances obtained from the plants themselves. On the other hand, in fields of industrial crops, all the organisms present are under severe control, through chemicals that prevent the growth of a large part of organisms, with the exception of what is cultivated.
- Open pit mines. When a deposit of a valuable material is discovered in a certain territory, it can be exploited through open-pit mining. While this form of mining is cheaper than others, it also impacts much more deeply on the ecosystem, creating one of its own. Vegetation on the surface is removed, as well as the upper layers of the rock. Plants do not survive in these mines, but insects and a multitude of microorganisms can exist. Due to the constant change made in the soil of the mines, no other animals settle.
- Greenhouse. They are a particular form of growing ecosystem in which temperatures and humidity are high, taking advantage of the concentration of solar energy in a delimited space. This ecosystem, unlike crop fields, is not affected by wind, rain or temperature changes, since all these factors (air movement, humidity, temperature) are controlled by man.
- Gardens. They are ecosystems similar to grasslands, but with a significantly lower variety of flora and fauna, since the flora is selected by man and the fauna usually includes only insects, small rodents and birds.
- Streams. They can be created artificially from a natural source (a river or a lake) or artificial (pumped water). A channel is dug with the desired shape and ensuring a slope in the right direction. The channel can be covered with stones or pebbles to ensure that erosion from the passage of water will not change the designed shape. The ecosystem of these artificial streams begins with the microorganisms that the water brings with it, depositing algae on the bottom and sides of the river and attracting insects. If the source is natural, it will also contain the animals (fish and crustaceans) that lived in the ecosystem of origin.
- Urban environment. Towns and cities constitute ecosystems that did not exist prior to human action. These ecosystems are the ones that have varied the most in recent centuries, significantly modifying the species that live in them, as well as the abiotic factors that interact with them. The only factor that has remained unchanged is the high concentration of human beings, although this has been increasing. The soils of both towns and cities are made of artificial materials (with a reduced amount of “green spaces” with natural soils). This ecosystem extends above the ground into the air space but also underground, forming houses, reservoirs, drainage systems, etc. Pests due to population density are common in this ecosystem.