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Biology 2nd Baccalaureate

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13.2. Types of ecosystems

Types of ecosystems

The  biosphere is a thin layer of the Earth, from about 10 km of altitude to the ocean floor, in which life develops.

Living beings cannot survive in isolation, but they need to relate to the environment that surrounds them, so each living being is related to others, of the same or of a different species.

Two different environments can be distinguished in the biosphere: the  aquatic environment  and the  terrestrial or aerial environment. In each of them there are millions of species of living beings, each of them adapted, as a consequence of natural selection, to certain environmental conditions.

Aquatic ecosystems

The  aquatic ecosystems are ecosystems whose biotope is a mass of water such as rivers, lakes, seas, oceans, swamps, etc.

Two types of aquatic ecosystems are distinguished:

  • Marine ecosystems. They are characterized by the high salinity of their waters, about 35 g/l, and include the seas and oceans.
  • Freshwater ecosystems. The concentration of its salts is less than 1 g/l, and includes rivers, lakes, wetlands, etc.

In aquatic ecosystems, the trophic level of producers, photosynthetic organisms, is made up of algae and phytoplankton, always in the surface area, where sunlight reaches them. The second trophic level, that of the primary consumers, will be zooplankton, made up of simple unicellular and multicellular organisms, which will feed on the first level. Subsequently, secondary  and tertiary consumers  intervene in the food chain.

The flow of energy begins in the phytoplankton, which captures solar energy, and moves to different levels, in the deepest areas of the sea. Decomposing organic matter settles to the bottom of the sea and takes a long time to re-enter the biological cycle.

Ecosistema acuático marino

Loro Parque (Puerto de la Cruz, Santa Cruz de Tenerife)

Answer in your notebook

13.2.- Describe the components of an aquatic ecosystem.

Terrestrial ecosystems

The  terrestrial ecosystems are ecosystems whose biotope is the soil and airThey are highly influenced by the climatic characteristics of each area.

According to the abiotic factors  of each ecosystem, different habitats are distinguished, such as deserts, grasslands and forests. The species of plants and animals in each habitat have different characteristics, since they have adapted to living in these conditions. If a species cannot adapt to these conditions, it disappears and may become extinct.

Examples of terrestrial ecosystems are the Mediterranean foresttundrasavannadesert, etc.

In terrestrial ecosystems, photosynthetic organisms, producers, live fixed to the ground. The herbivores, invertebrates and vertebrates, feed on leaves, fruits, roots, seeds, etc., of the producers. The carnivores hunt in different ways herbivores, such as wolves are predators, spiders weave their web, bats at night, scavengers like vultures, etc.). Decomposing organisms  recycle dead organic matter and it can be quickly reused by plants.

The flow of energy begins in photosynthetic organisms, which capture sunlight, and through photosynthesis, make organic matter from inorganic matter. Then it goes to herbivores, carnivores, and decomposers.

Ecosistema terrestre

Parque Nacional y Natural de Doñana (Almonte, Huelva)

Answer in your notebook

13.3.- Describe the components of a terrestrial ecosystem.

Urban ecosystems

Although within terrestrial ecosystems, we must point out a particular ecosystem, cities and their urban ecosystem. In the human environment, with its buildings, streets, cars, pollution, etc., there are characteristics that have allowed some living beings to adapt to them. For example, the temperature of cities is a couple of degrees higher than their surroundings.

The level of producing organisms is almost nil, since most of the food has an external origin and the trophic levels of the consumers predominate. Only in some parks and green areas can there be fruits, for example, that feed the primary consumers.

Although the main consumer is humans, other species such as dogs, cats, live with it. And others, such as pigeons, sparrows, ants, etc., which are also primary consumers. There may even be a bird of prey in our cities. The cycle of matter is not completed, since waste accumulates in landfills and some are even difficult to recycle.

In cities, a large quantity of drinking water is required, which is obtained from the water treatment plants and which has to go through the treatment plant before returning it to the river.

The energy used in cities comes from electricity consumption and fossil fuels that pollute the atmosphere.

Video: Meet the other inhabitants of our cities.

Answer in your notebook

13.4.- Describe the components of an urban ecosystem.


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