Biology

Biology (from Greek 'βιος' bios, life, and "λóγος 'logos, reason, study, science) is a branch of natural science which seeks to study living things and, more specifically, its origin, its evolution and its properties: genesis, nutrition, morphogenesis, reproduction, pathogenesis, and so on. It deals with both the description of the characteristics and behavior of individual organisms and species as a whole, and the reproduction of living beings and the interactions between them and the environment. Thus, trying to study the structure and functional dynamics common to all living beings in order to establish the general laws of organic life and the fundamental explanatory principles thereof.

The word "biology" in its modern sense seems to have been introduced independently by Gottfried Reinhold Treviranus (Biologie oder Philosophie der Natur lebende, 1802) and Jean-Baptiste Lamarck (Hydrogeology, 1802). Usually said that the term was coined in 1800 by Karl Friedrich Burdach, though mentioned in the title of the third volume of Philosophiae naturalis sive physicae dogmaticae: geology, biology, Phytologia generalis et Dendrology of Michael Christoph Hanov and published in 1766.

Fields of study


Biology is a scientific discipline that encompasses a wide range of fields of study that often are treated as separate disciplines. All of them together, study the life in a wide range of scales. Life is studied at atomic and molecular molecular biology in biochemistry and molecular genetics. From cellular standpoint, is discussed in cell biology and at multicellular studied in physiology, anatomy and histology. From the point of view of ontogeny or development of organisms at the individual, is studied in developmental biology.

When the field is extended to more than one organism, genetics is the operation of genetic inheritance from parents to offspring. The science dealing with the behavior of groups is the ethology, ie more than one individual. The population genetics observes and analyzes a population genetics and systematic whole is the lineages between species. Interdependent populations and their habitats are examined in ecology and evolutionary biology. A new field of study is astrobiology (or xenobiology), which studies the possibility of life beyond Earth.

The classifications of living beings are very numerous. Are proposed from the traditional division into two kingdoms established by Carolus Linnaeus in the seventeenth century, between animals and plants, to the current proposals for systems cladistic with three domains that comprise more than 20 kingdoms.

Branches of biology

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Anthropology: study of human beings as biological entity.
Botany: study of photosynthetic organisms (multiple kingdoms).
Mycology: the study of fungi.
Embryology: study of development.
Microbiology: the study of microorganisms.
Physiology: study of the bodily function of organisms
Genetics: study of genes and inheritance.
Evolution: study on change and transformation of species over time.
Histology: study of tissues.
Ecology: study of organisms and their relationship.
Ethology: study of the behavior of living things.
Paleontology: The study of organisms that lived in the past.
Anatomy: The study of internal and external structure of living things.
Taxonomy: A study that ranks and orders of living beings.
Phylogeny: a study of the evolution of living beings.
Virology: the study of viruses.
Cytology: study of the cells.
Zoology: the study of animals.
Epistemological Biology: study of the philosophical origin of biological concepts.
Biomedicine: A branch of applied biology to human health.
Immunology: Study of immune defense system.
Organography: study of organ systems.
Marine biology: study of marine life.


History of biology

The word biology was coined during the Enlightenment by two authors (Lamarck and Treviranus) that simultaneously use it to refer to studying the laws of life. The neologism was first used in France in 1802, by Jean-Baptiste Lamarck in his treatise on Hydrogeology. Unaware that in the same year, the German naturalist Treviranus had created the same neologism in a six-volume work entitled biology or philosophy of living nature, "biology will study various forms of life, conditions and laws governing their existence and causes that determine their activity. "

However, despite the recent coining of the term, biology has a long history as a discipline.


Principles of Biology

Unlike physics, biology does not usually describe biological systems in terms of objects which obey immutable laws described by mathematics. However, is characterized by certain principles and concepts of major importance, among which include universality, evolution, diversity, continuity, homeostasis and interactions.


Universality: biochemistry, cell and genetic code


Schematic representation of the molecule of DNA, the molecule carrying genetic information.

There are many universal constants and common processes that are essential to understanding life forms. For example, all life forms are composed of cells, which are based on a biochemical common, which is the chemistry of living things. All agencies perpetuate their characters inherited through genetic material, which is based on the nucleic acid DNA, which uses a genetic code universal. In developmental biology the property of universality is also present: for example, early embryo development follows some basic steps that are very similar in many organisms metazoan.

Evolution: the central principle of biology


One of the central concepts of biology is that all life descended from a common ancestor that has followed the process of evolution. In fact, this is one reason why biological organisms exhibit a similarity so striking in the units and processes that have been discussed in the previous section. Charles Darwin conceptualized and published the theory of evolution in which one of the principles is the natural selection (to Alfred Russell Wallace is generally acknowledged as co-discoverer of this concept). With the so-called modern synthesis of evolutionary theory, genetic drift was accepted as another key mechanism involved in the process.


Chromosomes

We know that DNA, ground substance of the material diffuse color (and is observed in cell rest), is structurally and functionally organized with certain proteins and certain forms Costituyentes abastonadas structures called chromosomes. The units of DNA are responsible for structural and metabolic characteristics of the cell and the transmission of these characters from one cell to otra.Estas are called genes and are arranged in a linear order along the chromosomes.