Species (biology)

Species . It comes from the Latin species. In biology , each of the groups into which the genders are divided is called, that is, the limitation of the generic in a specific morphological field. In biology, a species is the basic Unit of the biological Classification .


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  • 1 Definition
  • 2 Determination of limits
  • 3 Nomenclature
  • 4 Types of species
  • 5 Other classifications: cryptic, sympatric and synoptic species
  • 6 Alien species and invasive alien species
  • 7 The extinction of species
  • 8 Sources


A species is often defined as a group of Organisms capable of interbreeding and producing fertile Offspring . While in many cases this definition is adequate, more accurate or more differentiating measurements are often used, for example based on DNA similarity or the presence of specific locally-adapted traits.

It is a group of natural populations whose members can cross each other, but cannot – or at least do not habitually do so – with members of populations belonging to other species. In this concept, the isolation in the Reproduction with respect to other species is central.

Species: Animals

It is a group of organisms reproductively Homogeneous , but very changing throughout time and space. In many cases the groups of organisms that separate from the original population, and are isolated from the rest, can achieve sufficient differentiation to become a new species.

Determination of limits

The determination of the limits of a species is purely subjective and, therefore, exposed to the modalities of personal interpretation. Some usual concepts are ancient, long before the scientific establishment of this systematic category.

On the contrary, there are others with very vague limits, in which the systematics are in complete disagreement. If the species were immutable, each could be easily defined by saying that it is the set of individuals (who were, who are, and who will be, if not extinct) of qualitatively identical characters. An entity so determined is not really a species, but what is usually called a pure Line or a Clone .


The names of the species are Binominal , that is to say, formed by two words, which must be written in a typeface different from that of the general text (usually in italics; of the two words cited, the first corresponds to the name of the genus to which it belongs and it is always written with the initial in capital letter; the second word is the specific Epithet or specific name and must be written entirely in lowercase and must agree grammatically with the generic name). Thus, in Mantis religiosa , Mantis is the generic name, religiosa is the specific name, and the binomial Mantis religiosa designates this species of insect.

In the scientific name assigned to the species, the specific name should never be isolated from the generic one since it lacks its own identity and can coincide in different species. If the full name has been previously cited and there is no doubt which genus it refers to, the genus name may be abbreviated to its initial (M. religiosa).

Species types

In any Ecosystem we find populations of all kinds of species. The ecology studies the role that species play in the ecosystem and the various types of relations with each other.

Native and immigrant species: Species that naturally belonged to the ecosystem are called native or indigenous . The immigrant species are those that are deliberately or accidentally introduced into an ecosystem. Human activity has accelerated the introduction of new species into ecosystems.

Sometimes the result is beneficial – for example, to fight a Plague – but others are very harmful, because they become pests or eliminate other native species. This was the case with the introduction of the Rabbit in Australia or the Cats or other Mammals in many Pacific islands where they have led to the extinction of several species of Birds .

Generalist and specialist species: Generalist species, such as Man , Rat , Flies , etc. They can live in many different places, eat a wide variety of foods and smell very different . Environmental conditions .

Specialist species can only live under very specific nutritional or environmental conditions. Thus, for example, the panda bear feeds on bamboo leaves.

Other classifications: cryptic, sympatric and synoptic species

Cryptic species are those species that are difficult to distinguish by their external morphology, but which are different in internal, behavioral, molecular, and cytogenetic characters .

Already from the habitat point of view , sympatric species are recognized as those that coexist in the same area or territory, but not necessarily in the same habitats, and, as synoptic species, those that coexist in the same locality and overlap their habitats. .

Alien species and invasive alien species

The use of plant and animal species by human beings for the satisfaction of their needs, goes back to the origins of their own existence as a species.

From then until now, the introduction of species has taken place in areas other than those of these species. These species that reach a different area, by human means, are exotic species for that area.

The agriculture , fisheries, timber industry , the pet trade and horticulture are some of the practices through which the exchange of species is between different regions of the planet.

Sometimes by introducing a species, it can survive and adapt without causing great damage to its new environment, and with it the expected benefits are obtained from it.

In others, the introduced species come to cause serious negative effects for the new environment, including people, because they develop a different behavior than they had in their ecosystem of origin, as they do not have controlling factors characteristic of their natural distribution area in the new place. . Thus, it is accepted that exotic species that establish themselves in a new environment, proliferate and disperse destructively and negatively for the interests of man, are considered invasive alien species.

The natural controlling factors of species include predators, specific environmental conditions and competition for resources, among others, and are what keep populations at equilibrium levels in ecosystems where they have evolved naturally for long periods of time.

New behaviors of invasive alien species include uncontrolled growth of their populations and not shown aggressive behavior in their natural environment . Thus, these behaviors can be used when determining the invasiveness of a species.

The introductions of species made by man may be deliberate or not.

In the first case, they are organisms, often plants and animals , that are transferred to new destinations to satisfy economic and social interests.

Unintentional introductions are those in which species are transported in an unconscious or accidental way.

It has been verified that introduced species, whether or not deliberately, that have been established as invasive, cause impacts on ecosystems, agriculture, tourism and health, and cause serious economic, ecological and social losses.

The weeds , for example, reduce the volume of crops, reduce the water available to degrade watersheds and freshwater ecosystems.

Tourists unintentionally introduce exotic plants into national parks , thereby degrading protected ecosystems and increasing the costs of their proper management.

The pests and pathogens of crops, livestock and trees , destroy plants directly, or reduce harvests and force increase spending on pest control measures.

By discharging ballast water, harmful aquatic organisms, such as bacteria and viruses , enter marine and freshwater ecosystems; This degrades economic activities such as the fishery.

There are disease-carrying organisms that have recently begun to spread and have continued to kill or incapacitate millions of people every year, which have profound social and economic implications.

So far, approximately twenty plants and animals make up the group of prioritized invasive alien species in Cuba.

An important line of work for the prevention and control of invasive alien species, and with it the safeguard of biodiversity of global importance, is the awareness and education of citizens, in order to strengthen public awareness of this problem.

The extinction of the species

Generally, an endangered species is an organism in danger of disappearing from the face of the Earth if its situation does not improve. When members of a species have not been observed in natural environments for more than fifty (50) years, that species is said to be extinct. Those species that could be in danger in a short time are called threatened species . The rare species are those with small populations that could also be in danger.

Laws and regulations have been enacted in many countries to protect endangered species and the habitats on which they depend. These legal provisions establish the categories of danger; in most cases, at least two categories are recognized: immediate risk and threatened . In addition to these two official categories, Biologists also recognize another: rare species , for species that exist throughout their range but in relatively low numbers.

The main causes of extinction of species, or their endangered, are destruction of habitats, commercial exploitation (such as collecting plants, hunting, and marketing of animal parts), damage caused by plants and non-native animals introduced into a area, and environmental pollution . Of all these causes, direct habitat destruction is what endangers the greatest number of species.


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