In biology, a large number of species of living organisms that belong to different taxonomic units have already been studied to date. Related systematic groups of organisms are separated from other similar species, which simplifies the study of science in general and evolution in particular.
Science Systematics
This industry is engaged in the study and description of all the diversity of living things on planet Earth. Also, the main task of taxonomy is the grouping of organisms according to distinctive features, which in the future helps to draw up competent classification schemes.
In classifying animals, plants, bacteria, or protists, the concept of a taxon is often used. This term refers to a systematic group of organisms related by kinship and common distinguishing features.
Features of the systematization and classification of everything that exists are the main subjects of study of such a doctrine as taxonomy. The term is used not only in biology, but also in other fields (linguistics, bibliography).
Hierarchical Classification Systems
In any science that requires the systematization of its objects, it is necessary to distinguish common classification taxa. These can be large groups (in our case) of living organisms, taking into account common features.
From these classification taxa, several systematic groups of organisms related by kinship are subsequently formed. They usually have a number of distinctive and characteristic features, by which they differ from other objects of study of biologists.
If any two taxa do not have common features (do not intersect) or are subordinate to each other, then such a classification system can be called hierarchical.
The following examples can be given here: the Amphibians class and the Birds class do not intersect, because their representatives have little similarity. If we consider the order of Primates in the framework of the Mammals class, then both of these taxa are characterized by some common features, however, they are subordinate (the order is lower than the class in the biological systematics of animals).
Characteristics of a biological taxon
Attributes of any systematic group of organisms related by kinship are diagnosis, rank and volume.
1. Under the diagnosis understand all the distinguishing features of this taxon, which combine the corresponding species of organisms. Moreover, these distinctive features should be sufficient to limit the objects in a separate group.
2. The rank is the level of the taxonomic group within the framework of the classification scheme under consideration. Depending on it, these groups are subordinate and at the same time may have several common features.
3. If it is necessary to indicate the number of taxa of a lower rank, the concept of the volume of a systematic group is used. Now it is rarely used and is usually explained in Latin expressions sensu stricto or sensu lato (in the narrow sense and in the broad, respectively).
Biological classification
The systematization of various species of plants and animals is now firmly entrenched in many textbooks and teaching aids. Based on the above features of the hierarchical classification, all living organisms are divided into 5 kingdoms: plants, animals, fungi, protists and bacteria. There are also non-cellular life forms (viruses, viroids, virusoids, prions), which are considered separately.
Within the kingdoms of Plants, Mushrooms and Bacteria, the following taxonomic units are distinguished, which go by the decline of seniority:
- Kingdom.
- Department.
- Class.
- Order.
- Family.
- Rod
- View.
If we consider higher plants (according to the old classification), which include all terrestrial representatives, we studied 4 departments: bryophytes, ferns, gymnosperms and angiosperms. Sometimes fern-like species are divided into three separate taxonomic groups: coniferous, plauiform and fern-like.
Here is another distribution of taxonomic ranks:
- Kingdom.
- A type.
- Class.
- Detachment.
- Family.
- Rod
- View.
Such a hierarchical classification is used in the study of animals and protists.
The relationships within one systematic group of organisms are arranged vertically, however, from the point of view of the evolution of scientists, the “horizontal” classification of taxa is of interest.
For example, representatives of the type of Intestinal are more primitive in comparison with the type of Mollusks, but the latter are clearly inferior in evolutionary terms to the type of Mammals. As you can see, the taxonomic rank is the same, but the level of organization of the species in question is different.