What kingdoms of living organisms does biology study? Sections of biology and what they study
The name science of biology was given in 1802 by the French scientist Lamarck. In those days, it was still developing. And what does modern biology study?
Sections of biology and what they study
In general terms, biology studies the living world of the Earth. Depending on what modern biology is studying specifically, it is divided into several sections:
- molecular biology deals with the study of living organisms at the molecular level;
- section of biology, studying living cells - cytology or cytogenetics;
- living organisms - morphology, physiology;
- the biosphere at the level of populations and ecosystems is studied by ecology;
- genes, hereditary variability - genetics;
- embryo development - embryology;
- evolutionary biology and paleobiology are engaged in the theory of evolution and the oldest organisms;
- ethology studies animal behavior;
- general biology - the processes common to the whole living world.
There are also many sciences dealing withresearch of certain taxa. What are these sections of biology and what are they studying? Depending on which kingdoms of living organisms biology studies, it is divided into bacteriology, zoology, mycology. Smaller taxonomic units are also studied by separate sciences, for example entomology, ornithology, and so on. If biology studies plants, then science is called botany. Let us consider in more detail.
What kingdoms of living organisms does biology study?
According to the current theory, the living worldhas a complex structure and is divided into groups of different sizes - taxa. Classification of the living world is engaged in the biometric systematics. If an answer is needed to the question of which kingdoms of living organisms biology studies, it is necessary to turn to this science.
The largest taxon is an empire, and the living world consists of two empires - non-cellular (also known as viruses) and cellular.
From the name it is clear that the members of the first taxon do notreached the cellular level of the organization. Viruses can multiply only in the cells of another, cellular, host organism. The structure of the viruses is so primitive that some scientists do not even consider them alive.
Cellular organisms are divided into severalsupercars - eukaryotes (nuclear) and prokaryotes (pre-nuclear) The former have a decorated nucleus with a nuclear envelope, the latter do not. In turn, the supercarships are divided into kingdoms.
The kingdom of eukaryotes is composed of three kingdomsmulticellular - animals, plants and mushrooms, and one kingdom of unicellular - protozoa. In the realm of protozoa there are many heterogeneous organisms that have great differences. Sometimes scientists share protozoa in several groups, depending on the type of nutrition and other characteristics.
Prokaryotes are divided into the kingdoms of bacteria and archaea.
At present, scientists offer a different division of wildlife. Based on the signs, genetic information and differences in the structure of cells, three domains are distinguished:
- real bacteria;
- eukaryotes, which in turn are divided into kingdoms.
What kingdoms of living organisms are studying biology today:
Domain or kingdom of Archaean
Prokaryotic microorganisms live in the oceans,soil, intestines (involved in the digestion process), extreme conditions, such as hot springs and elsewhere. Prokaryotic cells do not have a nucleus and membrane organelles. Unlike bacteria, the archaea, the leading parasitic lifestyle, are unknown; they can not be considered pathogenic either, although there are studies pointing to the relationship between archean and periodontitis. All representatives of one species of Archaean have identical genetic material, since they lack meiosis - they reproduce asexually. Do not form a dispute, unlike other domains. They have a unique genome, different from eukaryotes and bacteria.
The kingdom (domain) of bacteria or eubacteria
Prokaryotes are usually unicellular, but sometimesForming colonies (cyanobacteria, actinomycetes). They do not have a core enclosed in the membrane, and membrane organelles. The cell of the bacterium contains a nucleoid unformed into the nucleus containing genetic information. The cell wall consists mainly of murein, although in some bacteria it is absent (mycoplasmas). Most bacteria belong to heterotrophs, that is, they feed on organic substances. But there are also autotrophs, for example, capable of photosynthesis - cyanobacteria, which are also called blue-green algae.
Some bacteria are useful - contained inintestinal microflora involved in digestion; some are harmful (pathogens of infectious diseases). People have long been able to use bacteria for their own purposes: for the production of food, medicines, fertilizers and so on.
The kingdom of protozoa
Includes all eukaryotes not related toanimals, plants and mushrooms. These include directly protozoa with a heterotrophic type of food, algae, mushroom-like protozoa. Usually protists are unicellular, but they are often capable of forming colonies. They live, as a rule, in a liquid or moist environment. Eukaryotic cells have a core and membranes. Reproduction is both sexual and asexual. There are the simplest parasites of man, animals and plants, causing various diseases (dysentery, malaria and others). At the same time, some types of protists are of benefit, forming limestone deposits or performing the function of sanitation of water bodies.
The Kingdom of Mushrooms
Eukaryotic organisms with heterotrophic typepower supply. Cells have one or more nuclei. The cell wall contains chitin. Characteristic is the symbiosis with higher plants and the formation of mycorrhizas. Propagate by arguments. The ability to unrestricted growth and immobility in the phase of vegetation give rise to fungi with plants. The body of the fungus consists of hyphae - long filaments. Mushrooms are useful, like those that people consume (ascomycete, bazinomycete). But many species of fungi are parasites or pathogens that cause human, animal and plant diseases that damage food. Some types of fungi, such as yeast or penicillin, people use for their own purposes.
The Kingdom of Plants
Eukaryotes; distinctive features -ability to unlimited growth, autotrophic type of nutrition (photosynthesis), motionless lifestyle. Cellular cellulose wall. Reproduction is sexual. They are divided into sub-kingdoms of lower and higher plants. Lower plants (algae), unlike higher plants (spore and seed), do not have organs and tissues.
Eukaryotic multicellular organisms withheterotrophic type of nutrition. Features - limited growth, ability to move. The cells form tissues; the cell wall is absent. Reproduction is sexual, in lower groups sexual and asexual alternation is possible. Animals have a nervous system of varying degrees of development.