Biology/Citable Version

Biology is the science of life. Biologists study all aspects of living things, including all of the many life forms on earth and the processes in them that enable life. These basic processes enable living things to harness energy, to synthesise the many different materials that make up their bodies, to assemble these materials to build organs and structures, to correct errors and repair injuries, to sense their environment and to make sense of it, to reproduce themselves, and to communicate with others.

Life forms have been of interest to all peoples throughout history, and the roots of biology go back to earliest known mankind. Curiosity about the nature of life, about the human body and how it works, and about all the things that make plants and animals different from objects and machines, runs deep in every human society. Much of the interest in living things stems from a wish to better exploit natural resources and to improve health, and has yielded detailed knowledge about plants and animals used to improve the standard of living. Not all plant and animal lore is biological science, however. Biology differs from simple curiosity about plants, animals, and the human body in using a systematic approach to study them, an approach that incorporates an understanding of mathematics, physics, chemistry and other sciences. Importantly, not all interest in knowing about living things comes about from a desire to apply that knowledge. The core of that desire a commonly felt need to understand the human condition and the nature of the world.

Biology asks some of the same questions that are found in religion and philosophy, questions such as "How did life begin?", and "What features separate something that is alive from something that is not alive?". The biologists' answers are different, because the biologist approaches these questions using the scientific method. Whether scientific thinking about such great issues as the origin of life on earth is compatable with religious doctrine is itself contentious. Some great thinkers, such as the physicist Albert Einstein, have found no real conflict between the varying teachings of science and religion, but consider Divinity and the Natural Universe to be one and the same (see Albert Einstein for detailed discussion with references).

Many independent scientific fields make up Biology, but all are related. Natural History (the study of individual species like white-tailed deer, sugar maple trees, box jellyfish and timber wolves) was one of the first areas of biology to develop. In natural history, whole organisms are studied in an attempt to make sense of the order of Nature. When the natural histories of plants and animals are considered in a context of how each affects the other and their environment, then the biologist's focus is on ecology. Some fields of biology are focused on the natural history of living organisms and their interactions within a certain realm of the earth, as in marine biology; other fields focus on particular aspects of the bodies of living organisms, like their structure (Anatomy) and function (Physiology). Studies of animals form the field of zoology, where as the study of plants is called botany. Medicine and the Health Sciences apply biology to understanding disease and to improving health. Many of the academic disciplines that make up the field of biology are listed at the bottom of this article along with a brief description. Further information about each is provided through links to other articles within Citizendium.

Etymology

(from Greek βίος λόγος) The word "Biology" is formed by combining the Greek βίος (bios), meaning 'life', and λόγος (logos), meaning 'study of'. "Biology" in its modern use was probably introduced independently by both Gottfried Reinhold Treviranus (Biologie oder Philosophie der lebenden Natur, 1802) and by Jean-Baptiste Lamarck (Hydrogéologie, 1802). Although the word "biology" is sometimes said to have been coined in 1800 by Karl Friedrich Burdach, it appears in the title of Volume 3 of Michael Christoph Hanov's Philosophiae naturalis sive physicae dogmaticae: Geologia, biologia, phytologia generalis et dendrologia, published in 1766.

The development of biology

• Roots of Biology in the Ancient World

The natural history of plants and animals was the first area of biology to develop.

• Early Biology : The Establishment of the Scientific Method

A workable classification of living things was made practical by Linneas using a form of systematic nomenclature he invented. This gives a unique name to each kind of plant and animal, and organizes all of them into a classification scheme that stresses similarities of physical features.

• First Glimpses of the Microscopic World

The features of plants and animals have often been understood on an entirely different levels with technological advances that provided new means for examining them. For example, the simple microscope in the hands of Antoni van Leeuwenhoek in the Seventeenth Century, revealed details of structure in the bodies of organisms that had never before been even suspected. Not only was the structure of flesh and plants seen at a new level of detail, but new types of organisms were also revealed: micro-organisms that could not be detected with the naked eye. Further developments led to the modern compound microscope by the end of the 19th century, with much higher resolution, and eventually the late 20th century electron microscopes.

Like all important technological advances in biology, the microsocope led to new ideas about living things. The concept that tissues were composed of cells was clarified, thefield of microbiology was born, and the ground was prepared for the germ theory of disease, an idea that helped bring the traditional practice of western medicine (sometimes called allopathy) into the field of health science and modern medicine.

Classification

Classification is the province of the disciplines of systematics and taxonomy. Taxonomy places organisms in groups called taxa, while systematics seeks to define their relationships with each other. This classification technique has evolved to reflect advances in cladistics and genetics, shifting the focus from physical similarities and shared characteristics to phylogenetics.

The dominant classification system is called Linnaean taxonomy, which includes ranks and binomial nomenclature. How organisms are named is governed by international agreements such as the International Code of Botanical Nomenclature (ICBN), the International Code of Zoological Nomenclature (ICZN), and the International Code of Nomenclature of Bacteria (ICNB). The PhyloCode is a formal set of rules governing phylogenetic nomenclature that is being established as an attempt to standardize naming in these three areas. The Virus cInternational Code of Virus Classification and Nomenclature (ICVCN) remains outside the PhyloCode.

Traditionally, living things have been divided into five kingdoms:

Monera -- Protista -- Fungi -- Plantae -- Animalia

However, many scientists now consider this five-kingdom system to be outdated. Modern alternative classification systems generally begin with the three-domain system:

Archaea (originally Archaebacteria) -- Bacteria (originally Eubacteria) -- Eukaryota

These domains reflect whether the cells have nuclei or not, as well as differences in the cell exteriors.

Further, each kingdom is broken down continuously until each species is separately classified. The order is 1) Kingdom, 2) Phylum, 3) Class, 4) Order, 5) Family, 6) Genus, 7) Species. The scientific name of an organism is obtained from its Genus and Species. For example, humans would be listed as Homo sapiens. Homo would be the Genus and Sapiens is the species. Whenever writing the scientific name of an organism it is proper to capitalize the first letter in the genus and put all of the species in lowercase; in addition the entire term would be put in italics. The term used for classification is called Taxonomy.

There is also a series of intracellular parasites that are progressively "less alive" in terms of metabolic activity:

Viruses -- Viroids -- Prions

Main topics and discoveries

• Evolution
• Common descent
• Homeostasis

Major discoveries in biology include:

• Cell theory
• Germ theory of disease
• Genetics
• Evolution
• DNA

Disciplines within biology

• Anatomy: The study of structure
• Biochemistry: The chemistry of living things is a field of both biology and chemistry
• Cell Biology: The study of the components of cells
• Genetics: The study of the inheritance of characteristics, genes and DNA
• Marine Biology: The study of life in the seas and oceans
• Behavior:
• Biodiversity:
• Biogeography:
• Botany:
• Developmental biology:
• Ecology:
• Ethology:
• Evolutionary biology:
• Molecular biology:
• Physiology:
• Zoology:

References

Citations

Further reading

Selected external links

The following links have been reviewed and are recommended because, at the time of their inclusion, they provided accurate information and portals to additional excellent web resources. Many other excellent links have been omitted through no fault of their own.

Plain and technical language

• The American Institute of Biological Sciences (ABIBS) Virtual Library is free to all visitors
• The Bio-Web reviews and gives access to information in Cell and Molecular Biology, includes "news" in plain language
• Cell and Molecular Biology Online is a resource for professionals that includes links and some information for all
• Kimball's Biology Pages represent an online biology textbook