The biology is the Science alive . Catch in the broad sense of sciences of alive, it recovers part of the Natural science and Natural history of the living beings (or having lived). However the distinction between organization S alive and nonalive is sometimes difficult and the determination of the specific object of biology does not have anything obvious.

Life presenting itself in so much forms and on scales so different that biology covers a very broad spectrum, which goes from the molecular level , while passing by that of the cell, then of the organization, up to the level of the Population and the ecosystem. These various levels show that the field of alive is strongly arranged hierarchically and as biology progresses, it specializes in multiple fields, all more or less related to the others.

During the History of biology, principles founders were discovered. Most important, which governs completely the field of living and even defining it are:

  • the evolution which makes that with each generation a Natural selection is carried out, bringing the alive characters of the being best adapted to a typical location to be likely more to be present in the following generations
  • the Hérédité, which ensures the transmission of the characters of an individual his descent

Etymology

The biology term is the composition of the two words Greek that bios (βιος) in French the life and logos (λογος) which means the study.

This word was defined at the end of the 18th century by the Naturaliste French Jean-Baptiste de Lamarck: All that is generally common to the vegetable and with the animal as all faculties which are specific to each one of these beings without exception, must constitute the single one and vast object of a particular science which is not founded yet, which does not even have a name, and to which I will give the name of biology.

Principles founders

Evolution

See also: Evolution (biology)

Although the idea of an evolution of the life is not a recent idea, it is only in 1859, with the publication of the Origin of the species of Charles Darwin that a scientific explanation was proposed with the introduction of the principle of Natural selection. With time, the original theory of Darwin was refined with the results of the experiments and observations which the biologists carried out. The theory currently making consensus is that of the synthetic Théorie of the evolution.

The evolutionary character of the life during was discussed very a long time and even is still questioned by certain people outside the scientific community, but none of these objections to the theory of the evolution is scientifically founded. The scientific community since very largely admitted the evolutionism of the life like a fact, which is shown by the experiment and the observation on several occasions in particular by:

  • the Fossil examination of the S in Paleontology watch evolution of forms of life through time
  • the Comparative anatomy which highlights the morphological similarities between animals however different
  • the Hérédité which explains the genetic variations of a generation to another
  • the comparative study of the Génome several organizations, which shows the more or less important distance in the Phylogenetic tree, thus making it possible to recall the evolution and the distance of the various forms of life
  • the artificial selection, which practiced by the Man at the animals and the plants that it has domesticated is the application by the Man of the principle of the natural selection

Diversity

See also: Biodiversity

If biology is so vast, it is because of the extreme diversity of alive which arises in so much forms that one can have of the evil to distinguish of the common points. A hierarchisation of alive was carried out all the same, which is the field of the Systématique and the Taxinomie. All the living beings are classified in three fields:

  • the Bacterium S
  • the archeobacteries
  • the Eucaryote S

Universality

Although being so different, all the forms of life share common characters. What carries to believe that the life on Earth originates in only one and even form of life, indicated under the Acronyme of LUCA (for Last universal common ancestor ), which would have appeared on Ground there is at least 2,5 billion years.

The principal universal characters of alive are:

  • the Carbon, which from its physical characteristics is used as " squelette" with all the organic compounds
  • the DNA and the ARN, which are used as support with the Génome and ensures the transmission of this last the descent at the time of the reproduction
  • the cell which is the smallest alive unit. This last point is discussed within the scientific community, because the Virus are regarded as alive by certain biologists, gold, they do not have a cell.

Fields of studies

Because of the extremely vast character of the subject, the study of biology requires a parcelling out in fields of studies. An approach, a little " réductrice" , but having the advantage of clarifying the topics, which consists in defining levels of organization. In a concern of arriving to a more total comprehension of biology, bridges were naturally created between the various disciplines.

Structure of the alive one

See also: Molecular biology, cellular Biology

The fields studying the structure of alive are on the scale of the Atome for the Molecular biology and of the cell for cellular biology.

The field of molecular biology studies the compounds of bases of alive, like DNA and the Protéine S. For a long time it was believed that the laws of the Chimie governing living it were different from those for the inanimate matter. But since the synthesis of many organic compounds, it is clearly allowed that the chemical laws are the same ones as for the inorganic matter. No vital Force insufflates the life with the matter as one thought it before with the vitalistic theory.

The development of the Microscope with which Robert Hooke discovered the cells in 1665 marked the birth of cellular biology and that of a world then unsuspected. This discovery and the many ones which followed made it possible to explain certain phenomena as what one qualified at the time of spontaneous Generation. It is on this scale that one meets the first living organisms.

Anatomy and physiology

See also: Histology, Physiology, Anatomy

Taken with the direction structural and functional, biology also recovers the whole of the disciplines, traditional and modern, which study structures like fabrics with the histology or the bodies with the anatomy. Physiology as for it studies the mechanical, physical and biochemical principles of the living organisms and is separate in two branches: the vegetable Physiology and the animal Physiology.

Diversity and evolution

See also: Systematic Taxonomy, , Biology of the evolution, Botanical, Zoology

The extreme diversity of alive does not prevent of anything the grouping in entities or Taxon S (Taxinomie), their relations the ones compared to the others and their classification (Systématique).

Interactions

See also: Ecology, Ethology

The interactions of the beings living between them and the bonds linking them with their environment is the field of ecology. The ethology as for it studies the animal behavior in the natural environment.

Levels of observation and disciplines

Applications

The applications of discovered in biology are many and very present in the daily newspaper of the human being. Important advances of these last decades in Médecine originate in mainly the discoveries on the operation of the human body. The pharmaceutical field also benefits from advanced in organic chemistry.

More recently, the discovery of the structure of the DNA and a better comprehension of heredity made it possible to modify the living beings finely and find applications in the fields agricultural and Agro-alimentaire.

Impacts on the company

Since the development of molecular biology and cellular physiology in the second part of the 20th century, progress of biology became daily and has an enormous impact on the company. Comprehension of the molecular mechanisms several hundreds of diseases, improvement of the treatments against cancer, comprehension of the neurological mechanisms and improvement of the treatment of the mental diseases, tracking of genetic tares in utero. A better comprehension of the molecular evolution, physical substrate with the evolution of the species, makes it possible to transpose to the man the discoveries made on the inferior animals, including worms like c. elegans or the fly drosophila, which one showed that the mechanisms molecular of segmentation of the body during embryogenesis are identical to those of the human one, and, in a general way, with all living it métazoaire.

However, very fast progress of biology causes sometimes philosophical interrogations, sharp concerns, even a strong opposition of certain associations or governmental organizations (ONG). Let us quote in particular: the Voluntary interruption of pregnancy (IVG), décriée by the catholics, the Cloning, the genetically modified organizations (GMO), the sequencing and the problems of intellectual Propriété who result from this (can one patent living it, titrated a magazine general public here are that a few years). These concerns are justified by the fact that biology, for the first time, is to two finger to be able to carry it out

See too

biology|biology

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