The scientific method of dividing organisms into large and small groups on the basis of their similarity among themselves was proposed by the Swedish naturalist Karl von Linney, a botanist, zoologist, naturalist, practitioner, pathologist, who published the scientific paper “Life System” in 1735. Although the book contained erroneous statements, it was a breakthrough in biology. Only during the lifetime of the author she was reprinted many times.
What Carl Linney proposed
Linnaeus is called the creator of the biological language. Some techniques were proposed by other naturalists earlier, but he was able to combine them into a harmonious system for both animals and plants. Linnaeus proposed the following:
- Group plants and animals according to similar characteristics into several taxa with a strict hierarchy.
- Each organism is given a name in Latin. It consists of two parts. Genus in biology is the first word in the name.
- The youngest rank is the species. The second word in the name of the organism, most often an adjective or noun in the genitive case, is written with a small letter.
- The free crossing of individuals of one species (i.e., the birth of fertile offspring) is a key sign of belonging to a species.
- An organism can be part of only one group at each level, therefore it receives a strict address in the biological system containing an exact sequence of ranks and an invariable binary name.
Now in biology, the genus, species, class, and other hierarchical levels seem familiar and even natural. But almost 3 centuries ago, this was a powerful impetus to development, which was extremely hindered by the lack of hierarchy and strict nomenclature. It is in this that Linnaeus sees great merit, of course, not the only one.
Many tried to introduce a classification of all living things on different grounds before it. But, given the diversity, even at that time of open and described species, it was a titanic work and at the same time an inspiration. After all, the signs by which systematization should have been carried out still had to be distinguished.
What is genus in biology
Briefly, a supraspecific taxonomic unit in the biological systematics of living organisms. In Latin, the genus is genus. Genus in biology is a singular noun in Latin. In the name of the organism, it is capitalized. It is sometimes abbreviated to a capital letter with a period. The word itself can be both the name of the naturalist who first discovered and described the species, and a noun borrowed from another language.
What kind of genus is in biology is quite difficult to say in terms of how precisely the species are combined in it. In general, they are similar in origin. That is, the remains of ancestors are known and found. Extinct species also have a strict place in the hierarchical system. So, a genus in biology is a concept similar to that in genealogy: representatives of a family whose ancestor was a common ancestor, for example, the Romanov dynasty.
It is much easier to describe the unifying characters, for example, for the class mammals or the order carnivores. Everything is clear from the name of the taxon.
Do representatives of one genus interbreed
A genus in biology is the penultimate rank, so the question of whether offspring of members of the same genus is possible is logical. But from the point of view of evolution, the point is not whether mating is possible, but will the couple have fertile offspring? And is endless mixing of species needed?
With interspecific crosses, the offspring are most often sterile. According to Haldane’s rule, a heterogametous hybrid that carries XY chromosomes not only in humans, but also in mammals in general, is often not viable and sterile. This is a man, male. Such destruction of hybrids is a natural protection of individual species from mixing.
In addition, there is a natural geographical protection - representatives of different species of the same genus do not live in the same range. For example, lions live in Africa, and tigers - in Asia. Their hybrid was born in a zoo, because in a natural environment, meeting is impossible.
Liger is a huge descendant of a lion (Panthera leo) and a tigress (Panthera tigris). It is sand color, but with fuzzy stripes. He was born when crossing two species of the same genus of panther in the cat family, with the lion being a male and the tiger a female. In the photo, the largest of the ligers is Hercules. According to Haldane’s rule, their females are fertile and the males are sterile.
Childbirth unites in families
The family is the next rank that unites several genera. If everything goes lower on the taxonomic system of biology from classes to species (family, genus and species), each rank becomes more numerous.
How are they designated? Most often, the name of the family is formed from the genus that is most typical of all in the taxon. The ending -idae in zoology or -aceae in botany is added to the root of the noun. For example, the cat family (Felidae) was named the genus of the cat (Felis) in its composition, and in the first photo of the article, representatives of the genus Primula (Primula) of the family Primrose (Primulaceae).
Example
In the photo, the location of the Ursus arctos brown bear in the biological system: Kingdom - Animals, Type - Chordates, Class - Mammals, Order - Carnivores, Family - Bears, Genus - Bears, Species - Brown bear.
The higher you move from species to senior ranks, the more unexpected “distant relatives” appear in the bear. But, according to the theory of evolution, they were all once united by a common ancestor.