What is called the body, and how it differs from other objects in nature?Under this concept to understand a living body that has a plurality of different properties.They distinguish the organism from non-living matter.In Latin organismus means "inform slender look," "arrange".The very name implies a specific structure of any organism.This research deals with the biology category.Living organisms are striking in their diversity.As some individuals are included in the species and populations.In other words - a structural unit of a certain standard of living.To understand what is called the body, it should be viewed from various aspects.
General classification
body as defined quite fully explain its essence, consists of cells.Experts identify such vnesistematicheskie categories of objects:
• celled;
• multicellular.
In a separate group of isolated such an intermediate category between the colonies of single-celled organisms.Their share in the general sense in the non-nuclear and nuclear.For the convenience of studying all of these objects are distributed across multiple groups.Thanks to this division into categories of living organisms (biology class 6) are summarized in an extensive biological classification system.
notion cells
definition of "organism" is inextricably linked with the category as a cell.It is a basic unit of life.This cell is the real carrier of all the properties of a living organism.In nature only viruses which are non-cellular form, do not have them in its structure.This basic unit of life and structure of living organisms possesses the totality of properties and mechanisms of metabolism.The cell is capable of independent existence, development and self-renewal.
The concept of a living organism is easy to fit into many bacteria and protozoa, which are single-celled organisms and multicellular fungi, plants, animals, consisting of a plurality of these units of life.Different cells have their own structure.So, in the prokaryotes include organelles such as the capsule, plasma membrane cell wall, ribosomes, the cytoplasm, the plasmid, nucleoid, flagellum, drinking.In eukaryotes, there are the following organelles: the nucleus, nuclear membrane, ribosomes, lysosomes, mitochondria, Golgi apparatus, vacuoles, vesicles, the cell membrane.
biological definition of "organism" is exploring an entire section of this science.Structures and processes of their life has been cytology.In recent years, it is more often called cell biology.
unicellular organisms
term "unicellular organism" means non-systemic category of objects, the body which has only one cell.It includes:
• prokaryotes that do not have formalized the cell nucleus and other internal organelles with membranes.They have no nuclear membrane.They have osmotrofny and autotrophic type of food (photosynthesis and chemosynthesis).
• eukaryotes, which are cells that contain a nucleus.
generally accepted that single-celled organisms were the first living entities on this planet.Scientists believe that the most ancient of them were archaea and bacteria.Unicellular protists are also often called - eukaryotic organisms, which are not included in the category of fungi, plants and animals.
multicellular organisms
multicellular organisms, the definition of which is closely related to the formation of the whole, is much more complex single-celled objects.This process consists of differentiation of various structures, which include cells, tissues and organs.The formation of a multicellular organism involves the separation and integration of various functions in ontogenesis (individual) and phylogeny (historical development).
multicellular organisms consist of many cells, many of which differ in structure and function.The only exceptions are the stem cells (in animals) and cambium cells (in plants).
multicellular and colonial
In biology distinguish multicellular organisms and colonies of single-celled.Despite some similarities of living objects, among them there are fundamental differences:
• multicellular organisms - is a community of many different cells, which have the structure and special features.Its body is made of different fabrics.For this organism have a higher level of integration of cells.They are characterized by their diversity.
• unicellular colonies are composed of identical cells.They are almost impossible to divide tissue.
boundary between colonial and multicellular fuzzy.In nature, there are living organisms, such as Volvox, which in its structure is a colony of single-celled, but they have somatic and generative cells, which differ from each other.It is believed that the first multicellular organisms appeared on our planet only 2.1 billion. Years ago.
Differences organisms from lifeless bodies
concept of a "living organism" refers to a complex chemical composition of the object.It contains proteins and nucleic acids.In this he differs from the bodies of inanimate nature.They also differ in their set of properties.Despite the fact that the body inanimate also possess a number of physicochemical properties, the term "organism" includes more numerous characteristics.They are much more diverse.
To understand what is called the body, is necessary to study its properties.So he has these characteristics:
• Metabolism, which includes food (intake of nutrients), selection (and removal of harmful waste products), movement (change of the position of the body or its parts in space).
• Perception and information processing, which include irritability, anxiety and allowing to perceive external and internal signals, and to selectively respond to them.
• Heredity, allowing transfer their descendants, and the variability of symptoms, which is a difference between individuals of the same species.
• Development (irreversible changes throughout life), growth (an increase in weight and size due to the processes of biosynthesis), reproduction (play like themselves).
classification based on the structure of the cells
Experts shared by all forms of living organisms 2 superkingdom:
• pre-nuclear (prokaryotes) - evolutionarily primary, the simplest type of cell.That they were the first forms of life on Earth.
• Nuclear (eukaryotes), derived from prokaryotes.This more advanced type of cell has a nucleus.Most living organisms on our planet, including humans, are eukaryotic.
Nuclear superkingdom, in turn, is divided into four kingdoms:
• protists (parafilitiechskaya group), which are ancestral to all other living organisms;
• mushrooms;
• plants;
• animals.
to prokaryotes include:
• bacteria, including cyanobacteria (blue-green algae);
• archaea.
characteristic features of these organisms are:
• lack of formalized the core;
• presence of flagella, vacuoles, plasmids;
• presence of structures in which photosynthesis occurs;
• form of reproduction;
• size of the ribosome.
Despite the fact that all organisms differ in the number of cells and their specialization, all eukaryotes are characterized by a certain similarity of the structure of the cell.They are distinguished by a common origin, so this group is a monophyletic taxon of the highest rank.According to scientists, eukaryotic organisms appeared on Earth about 2 million. Years ago.The important role played in their appearance symbiogenesis, is a symbiosis between a cell having a core and capable of phagocytosis, bacteria and absorbed by it.They were the forerunners of these important organelles like mitochondria and chloroplasts.
Mezokarioty
In nature there are living organisms that are intermediate between prokaryotes and eukaryotes.They are called mezokariotami.They are distinguished by their organization of the genetic apparatus.To this group of organisms are dinoflagellates (dinoflagellates).They have a differentiated nucleus, but in the structure of cells preserved traits of primitiveness that are inherent in the nucleoid.Type of organization the genetic system of these organisms is regarded not only as a transition, but also as an independent branch of development.
Microorganisms Microorganisms is a group living facilities, very small.They can not be seen with the naked eye.In most cases, their size is less than 0.1 mm.This group includes:
• denuclearized prokaryotes (bacteria and archaea);
• eukaryotes (protists, fungi).
vast majority of microorganisms are single cell.Despite this, in nature there are unicellular organisms which can be easily seen without a microscope, for example, Huge polikarion Thiomargarita namibiensis (marine Gram-negative bacterium).Study the life of such organisms microbiology.
Transgenic organisms
in recent times on hearing this phrase as the transgenic organism.What is it?It is an organism whose genome artificially introduced gene other living object.It is administered in the form of a genetic construct which is a DNA sequence.Most often it is a bacterial plasmid.Through such manipulations scientists to obtain organisms with qualitatively new properties.These cells produce a protein gene that has been introduced into the genome.
term "human organism"
Like any other living objects people studying science biology.The human body is a holistic, historically, dynamic system.It has a special structure and development.And the human body is in constant contact with the environment.Like all living things on Earth, it has a cellular structure.They form the fabric:
• epithelial, located on the surface of the body.It forms the skin and lining the walls of hollow organs and blood vessels inside.Also present in these tissues closed body cavities.There are several types of epithelium: skin, kidney, intestinal, respiratory.The cells that make up the fabric, are the basis of the modified structures such as nails, hair, teeth enamel.
• Muscle with properties contractility and excitability.Due to this tissue implemented motor processes inside the body and its movement in space.Muscles are composed of cells which are microfibrils (contractile fibers).They are divided into smooth and striated muscle.
• connecting, which include bone, cartilage, adipose tissue as well as blood, lymph, ligaments and tendons.All of its species have a common mesodermal origin, although each of them has its own function and structural features.
• nervous, which is formed by special cells - neurons (structural and functional unit) and glia.They differ in their structure.So a neuron consists of a body and two processes: short branching dendrites and long axons.The coated, they form nerve fibers.Functionally divided into motor neurons (efferent), sensory (afferent), intervening.Place the transition from one to the other of them is called the synapse.The main properties of the fabric: the conductivity and excitability.
What is called the human body in a broader sense?Four types of tissues form organs (part of the body with a certain shape, structure and function) and their systems.How are they formed?As with the implementation of certain functions of a single organ can not cope, they form complexes.What are they?Such a system - a collection of several bodies which have a similar structure, function and development.All of them form the basis of the human body.These include systems:
• musculoskeletal (bones, muscles);
• digestive (tract and prostate);
• respiratory (lungs, airways);
• sensory organs (ears, eyes, nose, mouth, vestibular system, skin);
• gender (male and female sexual organs);
• nervous (central, peripheral);
• circulatory (heart, blood vessels);
• endocrine (internal secretion glands);
• integumentary (skin);
• urinary (kidney, carve the way).
human body, the definition of which can be represented as a set of different organs and systems, has a major (the determining) the start - genotype.It is a genetic constitution.In other words - a set of genes of a living object obtained from the parents.Any type of microorganisms, plants and animals has distinct genotype.
