A person is inclined to systematize the objects of the world in order to generalize, which is convenient when talking. So, even in everyday life, for example, we generalize the objects used in the preparation and consumption of food products. We call this category “dishes”. The word “furniture” is constantly used in everyday life, which covers a table, a bed, and a wardrobe.
System in biology
The biosphere includes a huge number of species of living organisms. For the convenience of communication of all people, and especially biologists, scientists have identified systematic categories of different ranks. The result was a whole system of living organisms. Because wildlife is not just objects, but organisms that are related to each other. According to the theory of evolution, all living things came from one cell. That is, among living organisms there are close and distant relatives. Species close to each other fall into the general systematic category and make up the taxonomic group of living organisms in it.
In the course of the development of biology, a whole science has been formed that systematizes living beings. It is called systematics. Systematics distinguishes taxonomic groups of living organisms, which are united by similarity. They are also related to each other. That is, the taxonomic group is related organisms that are usually similar in appearance, physiologically and at the genetic level.
Ranks of systematic categories
Taxonomic groups in biology have a hierarchy:
- The basic unit of taxonomy is view. When naming an animal, we usually mean the kind of organism. Animals of the same species can produce offspring. Different types of living creatures in nature usually do not interbreed and do not produce offspring. Therefore, each species is well different from the rest.
- Next in the hierarchy is a systematic category called “genus”. This taxonomic group includes species related to each other, that is, descended from one common ancestor.
- The family is the next category of the animal and plant system. The family includes related genera of living organisms.
- The order includes one or more families, presumably descended from a common ancestor.
- The taxonomic group of animals of the category "class" includes one or more orders.
- The kingdom is a collection of related units of living organisms.
Kingdoms of wildlife
All living organisms are distributed by scientists into 8 kingdoms:
- Animals.
- Plants.
- Mushrooms.
- Bacteria.
- Viruses.
- Protista.
- Archean.
- Chromists.
What is a "domain"?
In turn, kingdoms are referred to as domains. A domain is the highest systematic category. Total domains 4:
- Eukaryotes.
- Bacteria.
- Archean.
- Viruses.
The number of species in taxa
Thus, taxonomic groups in the animal world, as well as plants and other organisms, are very different in the number of species included in them. For example, the systematic category “genus” may include one or several dozen species. One family may include one genus, two genera, or much more. There are families that include several thousand species.
Plant taxonomy
The taxonomic categories of the plant kingdom are somewhat different from the taxonomic groups of the animal kingdom.
The lower rank after the kingdom is “department”. Fifteen or sixteen departments of plants have been distinguished, depending on whether the taxonomy belongs to one or another scientist. The following are Class - Order - Family - Genus - Species. The "order" in the plant system corresponds to the "order" in the animal kingdom. The category “department” corresponds to the category “type”.
An example of a system in the plant world
Aspen belongs to the genus Poplar, the family of willow, the order of the ivory, the class of dicotyledons, the department of flowering plants, the kingdom of plants, the domain of eukaryotes. Aspen in scientific language is also called "trembling poplar."
The name of a species most often consists of two words, the first of which is a generic name, and the second is a species.
Latin in biology
In biology, the Latin language is widely used to understand the objects of nature by scientists around the world. Scientists know the Latin names of species of living organisms by heart or can compare from books. In the scientific literature next to the Russian name is always the name in Latin.
Plant varieties, breeds and subspecies of animals
Cultivated plants, within the same variety, often have many varieties. A domestic apple tree, for example, has several thousand.
Varieties are bred by people using the selection method. Unlike species, varieties are easily crossed with each other.
People breed new breeds of domesticated animals. Hatch more egg-laying chickens, meat breeds of pigs, more dairy cows and so on. New breeds of cats and dogs delight their owners.
Where does the many subspecies of animals come from? Many animal species have spread widely throughout the land. Evolving gradually, populations change both in appearance and in lifestyle. Subspecies are formed that can still produce common offspring.
Thus, taxonomic groups in biology have a different number of their constituent species or subspecies of living organisms. The higher the rank, the more species it covers.