Biotic and Abiotic Factors

We explain what biotic and abiotic factors are, how they are related and various examples. Also, what are food chains?

What are biotic and abiotic factors?

Biotic and abiotic factors are two of the central elements studied by ecology, that is, the scientific discipline that is dedicated to ecosystems to understand the way in which relationships are built between life and the inert elements that surround it.

So, the Biotic factors are those living beings that inhabit an ecosystem feeding on it, reproducing and serving as sustenance for other species. On the contrary, Abiotic factors are those that have their origin in inert matter That is, they are the set of chemical materials and physical forces that constitute the ecosystem and that exert certain specific effects on living beings.

All ecosystems are made up of these two types of factors between which more or less complex relationships are woven, which constitute the environment. Human beings are not exempt from this type of relationship, although they are distinguished from the rest of the animals in that they have the psychic and technological tools to modify the environment, instead of irremediably adapting to it, as other species do in their habitats. respective.

See also: Components of the environment

Biotic factors and examples

The term “biotic factors” refers, in essence, to the flora, fauna and funga of an ecosystem, that is, to the total species of plants, fungi and animals. Microorganisms can also be included (microflora and microfauna), depending on the level of detail with which the ecosystem is studied.

These biotic factors are characterized by their desire for survival, that is, they are organisms that fight to preserve internal order and continue existing, and by their reproductive capacity, that is, their innate tendency to produce more new individuals of the species. In this way, the different species of living beings that share a habitat are in continuous competition for available resources for food and the search for protection against natural elements (such as rain, cold or heat).

For this reason, many species make a continuous effort to control the necessary resources, whether it is food, territory, water or fertile females for reproduction, which they dispute both with other species (interspecific competition) and with other individuals of the species. its own species (intraspecific competition).

At the same time, many species build bonds of cooperation and mutual aid known as cooperative relationships (inter- and intraspecific): mutualism, in which both individuals or species benefit; commensalism, in which they share resources without particularly harming or benefiting each other; and symbiosis, in which they cooperate so closely that they depend on each other to survive.

Examples of biotic factors are:

• The animals: reptiles, fish, birds, mammals, worms, sponges, echinoderms, among many others.
• The microorganisms both multicellular and unicellular, such as bacteria, archaea and protozoans.
• The plankton of the seas: zooplankton (animal) and phytoplankton (plant).
• Fungi and yeast both free-living and parasitic.
• The plant species: trees, bushes, plants, vines, grasses, algae, among many others.

Food chains

The competitive relationships between living beings are complex and lead to the exchange of matter and energy between different species. That is to say, The matter that makes up the body of a living being is assimilated by another when it feeds on it as predators do when ingesting and digesting their prey. Furthermore, when the latter die, the matter in their bodies is assimilated by the decomposer species, thus returning to the circuit.

Depending on the place that a species occupies within this cycle of transmission of matter, also called food chain or trophic chain, we can distinguish between three sets of living beings:

• Producer or autotrophic organisms. Those that are capable of generating their own food from inorganic elements, such as water, sunlight or soil elements. In this group are plant species and a few other autotrophic organisms, which give rise to organic matter, transforming inorganic matter for their benefit.
• Consumer or heterotrophic organisms. Those that cannot generate their food from inorganic elements, but must consume the organic matter of other living beings. Those that consume organic matter from producing organisms are known as herbivores or primary consumers; while those who consume the organic matter of primary consumers (and other types of consumers) are known as carnivores or secondary consumers. For example: A deer is a primary consumer, since it feeds on leaves and stems; while a panther feeds on deer and is therefore a secondary consumer. Between one and the other there may also be other intermediate consumers.
• Decomposer or detritophagous organisms. Those that feed on the organic matter of producers and consumers, but once they have died and their body begins the decomposition process. Detritophages are responsible for recycling organic matter back into the circuit of life, since they not only feed on the body of deceased beings, but also decompose it into simpler substances that producers or autotrophs use for their benefit ( that is, organic fertilizer).

Abiotic factors and examples

The term “abiotic factors” encompasses a very diverse set of non-living components of an ecosystem such as water, air, sunlight, gases in the atmosphere or mineral components of the soil. These elements do not have a life of their own, but they are essential for the existence of living beings since they are used by producers to generate organic matter: plants, for example, use carbon dioxide, sunlight and water to produce organic molecules (sugars).

Furthermore, abiotic factors affect living beings in various ways, forcing them to adapt to their environment. The change in temperature in the cold seasons, for example, forces trees to lose their leaves to save water in times of low sunlight, and many animals to accumulate resources to hibernate during the worst weather.

Abiotic factors can be classified according to their nature into two sets:

• Chemical factors. Those that have to do with the constitution of matter, such as water, gases in the air (oxygen, hydrogen, nitrogen, among others) and mineral elements in the soil (calcium, iron, phosphates, among others).
• Physical factors. Those that have to do with natural forces, movement and energy, such as sunlight, environmental temperature, meteorological phenomena (rain, hail, snow, among others) or the forms of the earth's relief.

Finally, examples of abiotic factors are:

• solar radiation which provides light and heat to the Earth's surface.
• The different stages of water in its hydrological cycle: ice, liquid water, water vapor in the atmosphere or water droplets in precipitation.
• ambient temperature and atmospheric pressure, which determine the climate that changes cyclically throughout the year.
• Soil minerals rocks of different types and relief accidents.
• the tides caused by the attraction of the Moon.

Relationship between biotic and abiotic factors

Biotic and abiotic factors are continuously and closely related. On the one hand, abiotic elements serve as a starting point so that biotics can feed as in the case of autotrophic nutrition, or for respiration, a process in which living beings ingest gases useful for their metabolism, such as oxygen.

On the other hand, natural elements shape the ways in which living beings survive promoting an adaptive response on their part, that is, forcing them to protect their survival in different ways or to take advantage of moments of prosperity. Rain, for example, is essential for the life of plants and to cool the environment, keeping the climate stable.

So, in a very dry season, living beings must compete for available water, which can involve migration to wetter geographies and, therefore, the fight for territory with other species. Something different happens in deserts, whose continually dry environment encourages the adaptation of creatures, which develop over generations bodies and metabolisms capable of minimizing water consumption or retaining reserves of this substance inside.

Continue with: Landscape

References

• “Biotic factors” on Wikipedia.
• “Abiotic factors” on Wikipedia.
• “What are biotic and abiotic factors?” on the CCH Academic Portal of the National Autonomous University of Mexico (UNAM).