Variety of the living world. Levels of organization and basic properties

The diversity of the living world is almost impossible to express in quantitative terms. For this reason, taxonomists have grouped them into groups based on certain characteristics. In this article we will consider the basic properties, the basis of classification and the levels of organization of living organisms.

Variety of the living world: briefly

Each species existing on the planet is individual and unique. However, many of them have a number of similar features of the structure. It is on these grounds that all living things can be combined into taxa. In the modern period, scientists singulate five kingdoms. The variety of the living world (the photo shows some of its representatives) includes Plants, Animals, Mushrooms, Bacteria and Viruses. The latter of them do not have a cellular structure, and on this basis belong to a separate Kingdom. The virus molecule consists of a nucleic acid, which can be represented by both DNA and RNA. Around them is a protein membrane. With such a structure, these organisms are able to carry out only a single sign of living beings - to multiply by self-assembling inside the host organism. All bacteria are prokaryotes. This means that in their cells there is no formed nucleus. Their genetic material is represented by a nucleoid - circular DNA molecules, clusters of which are located directly in the cytoplasm.

Plants and animals differ in the way they eat. The former are able to synthesize organic substances themselves during photosynthesis. This method of nutrition is called autotrophic. Animals absorb already prepared substances. Such organisms are called heterotrophs. Mushrooms have signs of both plants and animals. For example, they lead an attached lifestyle and unlimited growth, but are not capable of photosynthesis.

Properties of living matter

And by what signs, in general, do organisms call living organisms? Scientists identify a number of criteria. First of all, this is the unity of the chemical composition. All living matter is formed by organic substances. These include proteins, lipids, carbohydrates and nucleic acids. All of them are natural biopolymers, consisting of a certain number of repeating elements. Signs of living beings also include food, breathing, growth, development, hereditary variability, metabolism, reproduction, adaptability.

Each taxon is characterized by its own characteristics. For example, plants grow unrestrictedly, throughout life. But animals grow in size only up to a certain time. The same goes for breathing. It is generally believed that this process occurs only with the participation of oxygen. This breath is called aerobic. But here some bacteria can oxidize organic substances and without the presence of oxygen - anaerobic.

The diversity of the living world: levels of organization and basic properties

The microscopic bacterial cell, and a huge blue whale, possess the indicated signs of the living. In addition, all organisms in nature are interconnected by the continuous metabolism of substances and energy, and are also necessary links in food chains. Despite the diversity of the living world, the levels of the organization assume the presence of only certain physiological processes. They are limited to the features of the structure and species diversity. Let's consider each of them in more detail.

Molecular level

The diversity of the living world, along with its uniqueness, is determined precisely by this level. The basis of all organisms are proteins, the structural elements of which are amino acids. Their number is small - about 170. But the composition of the protein molecule is only 20. Their combination causes an endless variety of protein molecules - from the reserve albumin of bird eggs to the collagen of muscle fibers. At this level, the growth and development of organisms as a whole, the storage and transfer of hereditary material, the metabolism and the transformation of energy are carried out.

Cell and tissue levels

Molecules of organic substances form cells. The diversity of the living world, the basic properties of living organisms at this level are already manifested in full. Unicellular organisms are widespread in nature. It can be both bacteria, plants, and animals. In such beings, the cellular level corresponds to the organism level.

At first glance, it may seem that their structure is rather primitive. But this is not so. Just imagine: one cell performs the functions of the whole organism! For example, the infusoria of the shoe moves with the flagellum, breathing through the entire surface, digestion and regulation of osmotic pressure by means of specialized vacuoles. Known in these organisms and the sexual process, which occurs in the form of conjugation. Multicellular organisms form tissues. This structure consists of cells that are similar in structure and function.

Organism level

In biology, the diversity of the living world is studied at this level. Each organism is a single whole and works in concert. Most of them consist of their cells, tissues and organs. The exception are lower plants, fungi and lichens. Their body is formed by a set of cells that do not form tissues and is called a thallus. The rhizoids perform the function of the roots in organisms of this type.

Population-species and ecosystem level

The smallest unit in taxonomy is the form. This is a collection of individuals with a number of common features. First of all, these are morphological, biochemical features and the ability to freely cross, allowing to inhabit these organisms within the same range and to give fertile offspring. More than 1.7 million species of modern taxonomy. But in nature they can not exist separately. Within a certain territory, several species live at once. This determines the diversity of the living world. In biology, a collection of individuals of one species that live within a certain range is called a population. From such groups they are isolated by certain natural barriers. These can be water bodies, mountain or forest tracts. Each population is characterized by its diversity, as well as its sexual, age, ecological, spatial and genetic structure.

But even within a single range, the species diversity of organisms is quite large. All of them are adapted to dwelling in certain conditions and are closely related trophically. This means that each species is a source of nutrition for another. As a result, an ecosystem or biocenosis is formed. This is already a collection of individuals already of different species, associated habitat, circulation of substances and energy.

Biogeocenosis

But with all organisms constantly interacting factors of inanimate nature. These include the temperature regime of air, salinity and chemical composition of water, the amount of moisture and sunlight. All living beings are dependent on them and can not exist without certain conditions. For example, plants eat only in the presence of solar energy, water and carbon dioxide. These are the conditions for photosynthesis, during which the necessary organic substances are synthesized. The totality of biotic factors and inanimate nature is called biogeocenosis.

What is the biosphere

The diversity of the living world on the broadest scale is represented by the biosphere. This is the global natural envelope of our planet, uniting all life. The biosphere has its limits. The upper, located in the atmosphere, is limited by the ozone layer of the planet. It is located at an altitude of 20 - 25 km. This layer absorbs harmful ultraviolet radiation. Above him, life is simply impossible. At a depth of 3 km is the lower boundary of the biosphere. Here it is limited by the presence of moisture. So only anaerobic bacteria can live deep. In the water shell of the planet - the hydrosphere, life is found at a depth of 10-11 km.

So, the living organisms that inhabit our planet in different natural environments have a number of characteristic properties. These include their ability to breathe, nourish, move, multiply, etc. The diversity of living organisms is represented by different levels of organization, each of which differs in the level of complexity of structure and physiological processes.