The name for the science of biology was given in 1802 by the French scientist Lamarck. In those days, it still began its development. And what does modern biology study?
Sections of biology and what they study
Generally speaking, biology studies the living world of the Earth. Depending on what modern biology studies specifically, it is divided into several sections:
- molecular biology studies living organisms at the molecular level;
- a section of biology that studies living cells — cytology or cytogenetics;
- living organisms - morphology, physiology;
- ecology studies the biosphere at the level of populations and ecosystems;
- genes, hereditary variation - genetics;
- embryo development - embryology;
- evolutionary biology and paleobiology study the theory of evolution and ancient organisms;
- ethology studies animal behavior;
- general biology - processes common to the entire living world.
There are also many sciences involved in the study of certain taxa. What are these sections of biology and what are they studying? Depending on which kingdoms of living organisms are studied by biology, it is divided into bacteriology, zoology, mycology. Smaller taxonomic units are also studied by individual sciences, for example, entomology, ornithology, and so on. If biology studies plants, then science is called botany. Let's consider in more detail.
What kingdoms of living organisms does biology study?
According to the prevailing theory now, the living world has a complex structure and is divided into groups of different sizes - taxa. The classification of the living world is handled by the biology systematics. If you need an answer to the question about which kingdoms of living organisms is studied by biology, it is necessary to turn to this science.
The largest taxon is an empire, and the living world consists of two empires - non-cellular (another name - viruses) and cellular.
From the name it is clear that the members of the first taxon did not reach the cellular level of organization. Viruses can multiply only in the cells of another, cellular, host organism. The structure of viruses is so primitive that some scientists do not even consider them alive.
Cellular organisms are divided into several kingdoms - eukaryotes (nuclear) and prokaryotes (prenuclear). The former have a shaped cell nucleus with a nuclear membrane, the latter do not. In turn, supra-kingdoms are divided into kingdoms.
The kingdom of eukaryotes consists of three multicellular kingdoms - animals, plants and fungi, and one kingdom of unicellular - the simplest. The kingdom of protozoa includes many diverse organisms with great differences. Sometimes scientists divide protozoa into several groups, depending on the type of food and other features.
Prokaryotes are usually divided into the kingdom of bacteria and archaea.
Currently, scientists offer another division of wildlife. Based on signs, genetic information and differences in the structure of cells, three domains are distinguished:
- archaea;
- real bacteria;
- eukaryotes, in turn dividing into kingdoms.
What kingdoms of living organisms is biology studying today:
Domain or kingdom of archaea
Prokaryotic microorganisms live in the oceans, soil, human intestines (participate in the digestion process), extreme conditions, such as hot springs and elsewhere. Prokaryotic cells lack a nucleus and membrane organelles. Unlike bacteria, archaea leading a parasitic lifestyle are unknown; they can also not be considered pathogenic, although there are studies indicating a link between archaea and periodontitis. All representatives of one archaea species have identical genetic material, since they do not have meiosis - they reproduce asexually. Do not form a dispute, unlike other domains. They have a unique genome that is different from eukaryotes and bacteria.
The kingdom (domain) of bacteria or eubacteria
Prokaryotes are usually unicellular, but sometimes forming colonies (cyanobacteria, actinomycetes). They do not have a nucleus enclosed in a membrane or membrane organelles. A bacterial cell contains an unformed nucleoid containing genetic information. The cell wall consists mainly of murein, although it is absent in some bacteria (mycoplasmas). Most bacteria belong to heterotrophs, that is, they feed on organic substances. But there are autotrophs, for example, capable of photosynthesis - cyanobacteria, which are also called blue-green algae.
Some bacteria are beneficial - those contained in the intestinal microflora are involved in digestion; some are harmful (pathogens of infectious diseases). Since ancient times, people have been able to use bacteria for their own purposes: for the production of food, medicines, fertilizers, and so on.
Kingdom of the simplest
Includes all eukaryotes not related to animals, plants, and fungi. This includes directly protozoa with a heterotrophic type of nutrition, algae, mushroom-like protozoa. Typically, protists are unicellular, but are often capable of forming colonies. They live, as a rule, in a liquid or humid environment. Eukaryotic cells have a nucleus and membrane. Reproduction is both sexual and asexual. There are simple parasites of humans, animals and plants that cause various diseases (dysentery, malaria and others). At the same time, some types of protists are beneficial, forming limestone deposits or serving as the orderlies of ponds.
The kingdom of mushrooms
Eukaryotic organisms with heterotrophic type of nutrition. Cells have one or more nuclei. The cell wall contains chitin. Symbiosis with higher plants and the formation of mycorrhiza are characteristic. Propagated by spores. The ability to unlimited growth and immobility in the vegetation phase is related by mushrooms with plants. The body of the fungus consists of hyphae - long strings. Mushrooms are useful, like those that people eat (departments of ascomycetes, basinomycetes). But many types of fungi are parasites or pathogens that cause diseases in humans, animals and plants, and damage products. Some types of mushrooms, such as yeast or penicillin, people use for their own purposes.
Kingdom of plants
Eukaryotes; distinctive features - the ability to unlimited growth, autotrophic type of nutrition (photosynthesis), an immovable lifestyle. Cellulose cell wall. Reproduction is sexual. They are divided into sub kingdoms of lower and higher plants. Lower plants (algae), unlike higher ones (spore and seed), do not have organs and tissues.
Animal kingdom
Eukaryotic multicellular organisms with heterotrophic type of nutrition. Features - limited growth, mobility. Cells form tissue; cell wall is absent. Reproduction is sexual, in lower groups alternation of sexual and asexual is possible. Animals have a nervous system of varying degrees of development.