Biological systematics is a science that is developing principles for classifying all existing living organisms and applying these principles to the construction of a holistic system. The classification of living organisms implies their description and hierarchical distribution in the system of organisms. According to one of these classifications, all living nature is divided into kingdoms.
The kingdoms of wildlife are the highest taxonomic categories in the system of the organic world. The division of existing wildlife into kingdoms is considered quite reasonable from the point of view of evolution. According to it, all organisms are divided into two supra-kingdoms (nuclear and nuclear organisms), which include four kingdoms: slugs, plants, fungi and animals. Each kingdom, in turn, is divided into sub-chapters. Consider the main categories in more detail.
Nuclear-free and pre-nuclear organisms (prokaryotes) - organisms that do not have a formalized cell nucleus. The genetic code has the form of a DNA ring chain and is present in the nucleotide without forming real chromosomes. These organisms do not have a sexual process. Scientists attribute various bacteria to prokaryotes, including blue-green algae.
The other three kingdoms of wildlife are eukaryotes. The first of these is plants. The most important difference between plants and other organisms is their ability to eat autotrophically, that is, to synthesize certain organic substances from inorganic ones. Green plants carry out photosynthesis using the energy of sunlight. Thanks to photosynthesis, the gas composition of the atmosphere is maintained. So, plants are the main source of energy and food for all organisms on our planet.
The classification scheme of plants is quite complicated. Initially, they are divided into lower and higher plants. The body of lower plants is not divided into root, stem and leaf. The lower plants include algae, namely blue-green algae, chrysophytes, siliceous, yellow-green, brown, red, euglena, green and other algae. Unlike lower plants, the bodies of higher plants are divided into the above specialized organs (leaf, stem, root). This includes mossy, fern, angiosperm plant types, within which separate classes are distinguished.
Mushrooms - the kingdom of wildlife, combining the characteristics of both animals and plants. Mushrooms, like plants, are motionless; they are characterized by apical growth and the presence of cell walls. From animals, mushrooms inherited a heterotrophic type of metabolism, the formation of urea, and other traits. Mushrooms reproduce vegetatively, sexually and asexually. They mineralize plant debris in the soil. Some species can cause plant and animal diseases. Found a large number of molds used today to obtain antibiotics, vitamins, hormones. It is no secret that many mushrooms are edible. Within this kingdom of wildlife, there are three types: real mushrooms, oomycetes and myxomycetes.
Representatives of the animal kingdom are characterized by some common properties with plants, among which, for example, metabolism and cellular structure. Such similarities are due to the unity of origin. However, the main distinguishing feature is nutrition. Animals are heterotrophs, that is, they feed on prepared organic compounds, due to the inability to synthesize them from inorganic substances. As a rule, animals are actively mobile. According to rough estimates, there are approximately two million species of animals. Like other kingdoms of wildlife, animals are divided into subcartes, types and species. So, there are unicellular and multicellular animals, dividing into dozens of types and species. One of these types includes people.