Species

Article

May 28, 2022

A species (lat. Species, abbreviation sp., Plural spp.) Is a group of organisms in biology whose offspring are able to reproduce with each other or which are similar in some other important ways. In taxonomic classification, organisms are classified into a hierarchical system that reflects the relationships between species. The basic unit for this classification is the species. More than four million of the species that live on Earth today have been described and named. Estimates of the actual number of species generally range from 5 to 30 million. Scientific species name According to the nomenclature rules used in biology, the scientific name of a species consists of two parts (Binomial Nomenclature), a surname and a species attribute. The latter is also called epithet in botany. For example, the human species name is Homo sapiens, where Homo means the human genus and sapiens is a species attribute, the Finnish translation of which in this case is “wise”. The birch, on the other hand, is Betula pubescens, where Betula is a genus of birches and an epithet of pubescens whose translation is “fluffy”. The last name can be used alone, as each family has a different name. On the other hand, the latter part of the species name alone is not useful, as several species belonging to different genera may have the same species attribute (for example, the genus of oaks has Quercus pubescens).

Species concepts

In practice, the species cannot be defined unambiguously, but different species concepts are used in different situations. No known definition applies to all forms of life.

Biological species concept

The most commonly used species concept is the biological species concept defined by Ernst Mayr, according to which organisms belong to the same species if they are able to produce reproductive offspring under natural conditions. According to this definition, a horse and a donkey are different species because their hybrids, or mules, are unable to reproduce. The advantage of a biological conception of a species is that it seeks to identify entities that are not merely a product of the human imagination, but that have real biological significance. The problem is that the biological concept of species is often difficult to put into practice. It is far from always possible to determine whether individuals from different populations can reproduce with each other. This is the case, for example, when populations live in different geographical areas and the individuals they belong to never meet in the wild. Geographical dispersal may prevent cross-breeding between populations that could reproduce if artificially introduced side by side. It is also impossible to determine the crossing capacity of fossil (extinct) species. The biological concept of species is not at all suitable for the classification of organisms that reproduce only asexually. Such are, for example, bacteria. Even the reproductive capacity of the offspring cannot be unequivocally classified as having or not having it. For example, in the case of a mule, most individuals are unable to reproduce, but there are also known cases in which a mule has been able to continue to breed. The gray gull and the gull living in Finland do not intersect with each other, but increasing intermediate forms of the species live around the northern hemisphere. According to the biological definition, gray gull and back gull are only the extremes of an unbroken ring species. In plants, demarcation is even more difficult. The European aspen (Populus tremula) and the North American aspen (Populus tremuloides) intersect into a viable hybrid ulcer (Populus × wettsteinii), but this intersection is non-reproducible. Many willows, considered different species, on the other hand, intersect quite easily. Although the fell