
Classification of Living Things Essay Sample
In biology, by the 1960’s, there was an idea of the levels of organization of living things as a concrete expression of the increasing complexity of ordering the organic world. Life on Earth is represented by organisms’ peculiar structure, belonging to certain taxonomic groups (species), as well as communities of varying complexity (biogeocenosis, biosphere). In its turn, the body is characterized by organization of organs, tissues, cells and molecules. On one hand, every organism consists of specialized subordinate organization systems (organs, tissues, etc.). On the other hand, it is, itself, relatively isolated unit of the super organism of biological systems (species, biogeocenoses and biosphere as a whole.)
The body is composed of various components, but at the same time due to their interaction, it is holistic. The species is a complete system, although its form separate units, namely the individuals, but their interaction and maintains the integrity of the species.
The existence of life on all levels provides a structure of lower rank. For example, the nature of the cell is determined by the level of organization of subcellular and molecular levels; the organism is determined by the organization of organ, tissue, and cellular levels; species is determined by the organization of the organism, etc.
There is the great similarity of units at lower levels of the organization and an increasing difference in the higher levels. Living world of our planet is infinitely diverse and includes a large number of species.
In fact, according to experts, there are twice more species, which is known to science in the world today. Annually, in scientific publications are described hundreds and thousands of new species.
Man has been surrounded always by many different creatures. Moreover, man was and remains substantially dependent on organisms, giving him food, medical supplies, raw materials and other important things. However, many of species are dangerous and harmful to humans. They are predators and poisonous organisms, parasites that are pathogens of domestic animals and humans, crop pests. Therefore, from the early phases, a person wanted to know the living organisms and their specific properties, characteristics, and mode of existence. And most important, it is significant to learn how to make distinguish between species and be able to navigate in their diversity.
In the process of understanding the numerous objects (objects, phenomena), and comparing their properties and characteristics people try to classify them. Then, similar objects are combined into groups. Differentiation of groups based on the differences between the subject matter. Thus, the system is constructed. The system covers all the studied objects (such as minerals, chemicals and organisms) and the relationships among them.
Biological taxonomy is the scientific discipline, which mission is to develop the principles of classification of living organisms and the practical application of these principles to the construction of the system. The classification means the description and location in the system of all existing and extinct organisms.
Taxonomy, as a separate biological discipline, deals with the problems of organisms’ classification and a system construction of nature.
Attempts to classify organisms date back to ancient times. Long time ago, there was a system developed by Aristotle in science (IV c. BC. E.). He divided all known organisms into two kingdoms: plants and animals. He used the stiffness and numbness of the first kingdom; then, he compared them with the second kingdom. In addition, Aristotle shared the animals into two groups: “animals with blood ‘and’ animals without blood ‘, which generally corresponds to the present division into vertebrates and invertebrates. Then he singled out a number of smaller groups, guided by different distinguishing features.
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Of course, from the standpoint of the modern science system Aristotle seems incomplete, but should take into account the level of actual knowledge of the time. His work is described only 454 species of animals and the possibility of research methods were very limited.
For almost two thousand years descriptive material in botany and zoology has been accumulated. The material provided a systematic development in the XVII-XVIII centuries. There was also the culmination in the original system of organisms Linnaeus (1707-1778), which was widely acknowledged in the world. Drawing on the experience of predecessors and new facts, that were found by Linnaeus, he laid the foundations of modern taxonomy. His book, published “System of Nature” was published in 1735.
Linnaeus took the form as the basic unit of classification, and he innovated into science such terms as “kind”, “family”, “force” and “class”. He retained the division of organisms to the kingdom of plants and animals. He proposed the introduction of binary nomenclature (which is used in biology to this day). He assigned a Latin name for each species,, which consists of two words. The first word (noun) was the genus name, which brings together a group of closely related species. The second word (usually an adjective) was the name of the form itself. For example, the types of “Buttercup pungent” and “creeping buttercup”, “goldfish gold” and “silver carp.”
Later, at the beginning of the XIX century, Georges Cuvier introduced in the concept of “type” as the ultimate unit of classification of animals.
The appearance of evolution theory of Charles Darwin (1859) had particular importance in the formation of modern taxonomy Scientific systems of living organisms created before Darwin were artificial. They joined a group of organisms by similar external characteristics rather formally. Darwin’s ideas have provided a method of constructing a science of the natural system of the living world. This means that it has to be based on some of the essential and fundamental properties of classified objects (organisms).
By the analogy, it could build a “natural system” of objects, such as books; for example, the personal library. If desired, the books can be arranged on the shelves of cabinets, or grouped by size or the color of the roots. In these cases, the “artificial system” will be created as “objects” (books), that is classified by minor properties. “Natural” will be a “system”, a library where the books are grouped according to their content. In this cabinet is located nonfiction: on one shelf there are books on physics, on the other there are books on chemistry, etc. Thus, there is a classification of books on the main property. Having now the “natural system”, it is easy to focus on a multitude of “objects”.
The fundamental basis of modern taxonomy is an idea about the unity of the origin of living organisms and organic evolution that led to the current diversity of these organisms. Guided by such ideas, modern science builds a natural system based on phylogenetic relatedness classified organisms (i.e., common descent, proximity and distance of the relationship between different species). The degree of relatedness of the species is established on the basis of their morphological, anatomical, biochemical, genetic, and other similarities and differences.
To build a system of organisms there were used hierarchy (subordination), and taxonomy (systematic) units. Types are grouped into genera, genera are grouped into the family, the families are grouped into teams, groups are grouped into classes, and classes are grouped into types. The different types are combined in the kingdom. Taxonomic unit of higher rank unites organisms to the largest and the most significant, important and fundamental characteristics. The lower rank has more specific, subordinate evidence, by which species are grouped within this taxon.
Throughout the XX century, systematic has been developing. This process is now continuing too. Thanks to advances in various fields of biology and other sciences the factual material is accumulated. This is a cause of serious review the existing systems of living organisms.
Aristotle divided all living things on the set of the two kingdoms: plants and animals. Such an idea was maintained almost in the middle of the XX century when began the fundamental restructuring of the system of a higher taxon. In 1934, E. Shatton (French microbiologist) offered to provide the bacteria into a particular over-kingdom that is called prokaryotes.
Only in the 1970s, through the electron microscopy and molecular biology, people were able to establish the fundamental differences between prokaryotic and eukaryotic organisms, which consist primarily of the cellular organization of representatives of this superkingdom. For several years, it concerns the allocation of the new (third) eukaryotic kingdom called fungi, proposed in 1969 by RG Whittaker (American ecologist), and immediately accepted in the scientific world. Mushrooms previously had been included in the plant kingdom. Although, they had been different from metabolism, the characteristics of cell organization, and many other features.
Currently, it is discussed the allocation of another kingdom of eukaryotic organisms (kingdom Protista), which differ from all other eukaryotes that are mostly single-celled forms, and metazoans (more precisely – colonial). Thus, in this kingdom should be attributed the simple, many algae and some fungi, previously included in three different kingdoms: animals, plants and fungi, respectively.
About two decades ago, in the macrosystem of prokaryotic organisms, scientists began to differ a new kingdom called archaea. Representatives of this group attracted the attention of biologists. Being undeniably prokaryotic organisms (i.e., the unlabeled nuclei in the cell), they are close to eukaryotes by the organization of the genetic apparatus, a number of biochemical properties, particularly metabolism.
Summarizing all the above, the final stage of the taxonomy is the creation of the natural system, which reflects the view of certain groups of living organisms. It is assumed that this system, on the one hand, is the heart of nature, and on the other hand, it is only a step of scientific research.