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11.1.1. Biotope

Biotope

The biotope is the place or the physical environment in which the living beings of an ecosystem live. It includes a substrate (soil, water , air , rocks , etc.) and the physical and chemical conditions of that medium (temperature, humidity, light, etc.).

These abiotic components condition the life of the organisms that live in the ecosystem.

Environmental factors are called the set of physical and chemical conditions that influence the biotope and the life of living beings in the ecosystem.

The main abiotic environmental factors are:

  • The light. It is necessary for photosynthetic organisms (and non-photosynthetic organisms) and determines their situation in the ecosystem. Photosynthetic autotrophs need energy from the sun to carry out photosynthesis. Trees sometimes struggle to capture more light by growing larger than the other trees next to them.
  • The water. It is essential for organisms to carry out their vital functions.
  • The temperature. Almost all living things need a certain temperature, usually between 0 and 50 ºC in order to live. According to how they regulate temperature, two types of organisms are distinguished:
    • Homeotherms or endotherms. They maintain their body temperature within limits, regardless of the environmental temperature. For example, mammals and birds.
    • ectotherms. They regulate their temperature depending on the ambient temperature. For example, reptiles , insects , etc.
  • The salinity of the water. It refers to the quantity of mineral salts dissolved in the water (freshsaltybrackish).
  • The pH. Indicates the degree of acidity or basicity of the medium in which organisms live.

Environmental factors influence the living beings in the ecosystem. Between all of them there is a balance that means that, generally, when one of these factors varies, there are changes in the rest of the other factors.

Main abiotic factors
Terrestrial environment Air environment Aquatic environment
Physical abiotic factors

Absence of light

Soil texture

Temperature

Precipitation

Solar radiation

Humidity

Temperature

Depth

Solar radiation

Turbidity

Currents

Chemical abiotic factors

Soil nature

Nutrients

Amount of oxygen

Salinity

Nutrients

Amount of oxygen

Answer in your notebook

Think and describe two adaptations that some organisms present to some of the abiotic factors that we have seen in the text.

Adaptations to the terrestrial environment

Absence of light

Organisms that live underground do not need to see, so many have lost the ability to see.

ScalopusAquaticus.jpg
By Kenneth Catania, Vanderbilt University, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=8923296

Soil texture

The size of the organisms has been reduced enough to be able to live and move in a medium with a grainy texture.

Ants Eating A Caterpillar.jpg
By Jeff Turner from Santa Clarita, CA, United States - Ants Eating A Caterpillar, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=7399396

Soil nature

Some plants can only live in a certain type of characteristic soil, be it acidic or basic.

Nutrient shortage

Some plants, such as carnivorous plants, have had to develop mechanisms to obtain a supply of extra nutrients that they cannot obtain in the environment in which they live.

Digested flyFile:Digested fly.JPG - Wikimedia Commons. (s. f.). Recuperado 21 de agosto de 2016, a partir de https://commons.wikimedia.org/wiki/File:Digested_fly.JPG

Amount of oxygen

Living beings develop the necessary breathing mechanisms to capture oxygen, such as the cutaneous respiration of amphibians.

Cochranella spinosa.jpg
bgv23, CC BY 2.0, via Wikimedia Commons

Adaptations to the aerial environment

Temperature

The temperature of the ecosystem is not constant, sometimes there are large differences in temperature between day and night and between summer and winter. That is why living beings have had to adapt their organism to these temperature variations. For example, seeds can hold out for a long time in adverse conditions until the right conditions arrive and they germinate. Animals have also adapted to the cold by covering themselves with hair, or with a layer of fat, for example.

Precipitation - Environmental humidity

Plants have also adapted to arid zones with strategies that avoid desiccation, such as cacti, which have reduced the size of their leaves to spines and their stems have specialized in accumulating water.

Animals have also adapted to prevent moisture loss with hair, feathers, exoskeletons, etc. This prevents drying out. In addition, the breathing systems are internal and do not need water.

Solar radiation

Plants grow more or less, depending on their light needs. If they need a lot of light, they will grow larger so they can catch it more easily.

Animals have also adapted to daylight or to being more active at night, depending on the needs of each species.

Adaptations to the aquatic environment

Depth - Solar radiation - Turbidity

As in the terrestrial environment, aquatic photosynthetic organisms are the base of the food chain. They are responsible for manufacturing organic matter with the help of the sun's energy, and this will pass to the rest of the organisms through food webs. Photosynthetic organisms need sunlight, but the amount of light that reaches them depends on the depth and turbidity of the water. Depending on the needs of each species, they will live at different depths.

Currents

Both algae and fish have hydrodynamic shapes that facilitate their movement in the water.

Salinity

Most of the organisms are adapted to live in certain conditions of salinity, or fresh water or salt water. It is very rare that some species can live in fresh and salt water, such as salmon.

Amount of oxygen

The respiratory systems (gills) of aquatic organisms are external to facilitate the absorption of dissolved oxygen in the water.