Dictionary Definition
biology
Noun
1 the science that studies living organisms [syn:
biological
science]
2 characteristic life processes and phenomena of
living organisms; "the biology of viruses"
3 all the plant and animal life of a particular
region [syn: biota]
User Contributed Dictionary
English
Etymology
sc=polytonic + sc=polytonicPronunciation
- /ˌba.ˈjɔ.lə.dʒɪ/
Noun
Translations
science of living matter
- Albanian: biologji
- Bosnian: biologija
- Catalan: biologia ^
- Chinese:
- Croatian: biologija
- Czech: biologie
- Danish: biologi
- Dutch: biologie
- Esperanto: biologio
- Estonian: bioloogia
- Finnish: biologia
- French: biologie
- Galician: biología
- German: Biologie
- Greek: βιολογία
- Hebrew: ביולוגיה (biologia)
- Hindi: जीवविज्ञान (jīvavigyān)
- Icelandic: líffræði
- Ido: biologio
- Interlingua: biologia
- Italian: biologia
- Japanese:
- kanji: 生物学
- hiragana: せいぶつがく
- romaji: seibutsugaku
- hiragana: せいぶつがく
- kanji: 生物学
- Korean: 생물학
- Latin: biologia
- Latvian: bioloĝija
- Lithuanian: biologija
- Maltese: bioloġija
- Novial: biologia
- Persian: (zīst-šenāsi)
- Polish: biologia
- Portuguese: biologia
- Romanian: biologie
- Russian: биология
- Scots: biologie
- Scottish Gaelic: bith-eòlas
- Serbian:
- Sindhi:
- Spanish: biología
- Swedish: biologi
- Turkish: biyoloji
- Urdu: حیاتیات (hiatiyaat)
Derived terms
See also
Extensive Definition
<div class="thumb tright"
style="background-color: #f9f9f9; border: 1px solid #CCCCCC;
margin:0.5em;"> Biology studies the variety of life (clockwise from top-left)
E. coli,
tree
fern, gazelle,
Goliath
beetle
Biology (from Greek
βιολογία - βίος, bio, "life"; and λόγος, logos, "speech" lit. "to talk
about life"), is a branch of Natural Science, and is the study of
living organisms and how they react to their environment. Biology
deals with every aspect of life in a living organism. Biology
examines the structure, function, growth, origin, evolution, and
distribution of living things. It classifies and describes organisms, their functions, how
species come into
existence, and the interactions they have with each other and with
the natural
environment. Four unifying principles form the foundation of
modern biology: cell theory,
evolution, genetics and homeostasis.
Biology as a separate science was developed in the
nineteenth century as scientists discovered that organisms shared
fundamental characteristics. Biology is now a standard subject of
instruction at schools and universities around the world, and over
a million papers are published annually in a wide array of biology
and medicine journals.
Most biological sciences are specialized
disciplines. Traditionally, they are grouped by the type of
organism being studied: botany, the study of plants;
zoology, the study of
animals; and microbiology, the study of
microorganisms. The fields within biology are further divided based
on the scale at which organisms are studied and the methods used to
study them: biochemistry examines the
fundamental chemistry of life; molecular
biology studies the complex interactions of systems of
biological molecules; cellular
biology examines the basic building block of all life, the
cell;
physiology examines
the physical and chemical functions of the tissues and organ
systems of an organism; and ecology examines how various
organisms and their environment interrelate.
Foundations of modern biology
There are five unifying principles of biology :- Cell theory. Cell Theory is the study of everything that involves cells. All living organisms are made of at least one cell, the basic unit of function in all organisms. In addition, the core mechanisms and chemistry of all cells in all organisms are similar, and cells emerge only from preexisting cells that multiply through cell division. Cell theory studies how cells are made, how they reproduce, how they interact with their environment, what they are composed of, and how the materials that make up a cell work and interact with other cell sections.
- Evolution. Through natural selection and genetic drift, a population's inherited traits change from generation to generation.
- Gene theory. A living organism's traits are encoded in DNA, the fundamental component of genes. In addition, traits are passed on from one generation to the next by way of these genes. All information flows from the genotype to the phenotype, the observable physical or biochemical characteristics of the organism. Although the phenotype expressed by the gene may adapt to the environment of the organism, that information is not transferred back to the genes. Only through the process of evolution do genes change in response to the environment.
- Homeostasis. The physiological processes that allow an organism to maintain its internal environment notwithstanding its external environment.
- Behavior. All living organisms exhibit a stimulus-response behavior.
Cell Theory
The cell is the fundamental unit of life. Cell
theory states that all living things are composed of one or more
cells, or the secreted
products of those cells, for example, shell and
bone. Cells arise from
other cells through cell
division, and in multicellular organisms, every cell in the
organism's body is produced from a single cell in a fertilized egg.
Furthermore, the cell is considered to be the basic part of the
pathological processes of an organism.
Evolution
A central organizing concept in biology is that
life changes and develops through evolution and that all
lifeforms known have a common origin (see Common
descent). This has led to the striking similarity of units and
processes discussed in the previous section. Introduced into the
scientific lexicon by Jean-Baptiste
de Lamarck in 1809,Charles
Darwin established evolution fifty years later as a viable
theory by articulating its driving force, natural
selection (Alfred
Russel Wallace is recognized as the co-discoverer of this
concept as he helped research and experiment with the concept of
evolution). Darwin theorized that species and breeds developed
through the processes of natural
selection as well as by artificial
selection or selective
breeding. Genetic
drift was embraced as an additional mechanism of evolutionary
development in the modern
synthesis of the theory.
The evolutionary history of the species— which
describes the characteristics of the various species from which it
descended— together with its genealogical relationship to
every other species is called its phylogeny. Widely varied
approaches to biology generate information about phylogeny. These
include the comparisons of DNA
sequences conducted within molecular
biology or genomics, and comparisons of
fossils or other records
of ancient organisms in paleontology. Biologists
organize and analyze evolutionary relationships through various
methods, including phylogenetics, phenetics, and cladistics. For a summary of
major events in the evolution of life as currently understood by
biologists, see evolutionary
timeline.
Up into the 19th
century, it was commonly believed that life forms could appear
spontaneously under certain conditions (see spontaneous
generation). This misconception was challenged by William
Harvey's diction that "all life [is] from [an] egg" (from the
Latin
"Omne
vivum ex ovo"), a foundational concept of modern biology. It
simply means that there is an unbroken continuity of life from its
initial origin to the present time.
A group of organisms share a common
descent if they share a common ancestor. All organisms on the Earth both living and
extinct have been or are descended from a common ancestor or an
ancestral gene pool. This
last universal common ancestor of all organisms is believed to have
appeared about 3.5
billion years ago. Biologists generally regard the universality
of the genetic code
as definitive evidence in favor of the theory of universal common
descent (UCD) for all bacteria, archaea, and eukaryotes (see: origin of
life).
Evolution does not always give rise to
progressively more complex organisms. For example, the process of
dysgenics has been
observed among the human population.
Gene theory
Biological form and function are created from and
passed on to the next generation by genes, which are the primary
units of inheritance. Physiological adaptation to an organism's
environment cannot be coded into its genes and cannot be inherited
by its offspring (see Lamarckism).
Remarkably, widely different organisms, including bacteria, plants,
animals, and fungi, all share the same basic machinery that copies
and transcribes DNA into proteins. For example, bacteria with
inserted human DNA will correctly yield the corresponding human
protein.
The total complement of genes in an organism or
cell is known as its genome, which is stored on one or
more chromosomes. A
chromosome is a single, long DNA strand on which thousands of
genes, depending on the organism, are encoded. When a gene is
active, the DNA code is transcribed
into an RNA copy of the gene's information. A ribosome then translates
the RNA into a structural protein or catalytic protein.
Homeostasis
Homeostasis is the ability of an
open system to regulate its internal environment to maintain a
stable condition by means of multiple dynamic
equilibrium adjustments controlled by interrelated regulation
mechanisms. All living organisms, whether unicellular or multicellular, exhibit
homeostasis. Homeostasis exists at the cellular level, for example
cells maintain a stable internal acidity (pH); and at the level of
the organism, for example warm-blooded
animals maintain a constant internal body temperature. Homeostasis
is a term that is also used in association with ecosystems, for example, the
atmospheric concentration of carbon
dioxide on Earth has been regulated by the concentration of
plant life on Earth because plants remove more carbon
dioxide from the atmosphere during the daylight hours than they
emit to the atmosphere at night. Tissues
and organs
can also maintain homeostasis.
Punnent Square made by Reginald Punnet in 1905
which is the shorthand way to show the expressed trait
See also: Health.
Research
Structural
Molecular
biology is the study of biology at a molecular level. This field
overlaps with other areas of biology, particularly with genetics and biochemistry. Molecular
biology chiefly concerns itself with understanding the interactions
between the various systems of a cell, including the
interrelationship of DNA, RNA, and protein synthesis and learning
how these interactions are regulated.
Cell biology
studies the physiological properties of
cells, as
well as their behaviors, interactions, and
environment.
This is done both on a microscopic and molecular level. Cell biology
researches both single-celled organisms like bacteria and specialized cells
in multicellular organisms like humans.
Understanding cell composition and how they
function is fundamental to all of the biological sciences.
Appreciating the similarities and differences between cell types is
particularly important in the fields of cell and molecular biology.
These fundamental similarities and differences provide a unifying
theme, allowing the principles learned from studying one cell type
to be extrapolated and generalized to other cell types.
Genetics is the
science of genes, heredity, and the variation of
organisms. Genes encode the
information necessary for synthesizing proteins, which in turn play
a large role in influencing (though, in many instances, not
completely determining) the final phenotype of the organism. In
modern research, genetics provides important tools in the
investigation of the function of a particular gene, or the analysis
of genetic
interactions. Within organisms, genetic information
generally is carried in chromosomes, where it is
represented in the chemical
structure of particular DNA molecules.
Developmental biology studies the process by
which organisms grow and develop. Originating in embryology, modern
developmental biology studies the genetic control of cell growth,
differentiation,
and "morphogenesis," which is
the process that gives rise to tissues,
organs,
and anatomy. Model
organisms for developmental biology include the round worm
Caenorhabditis
elegans, the fruit fly Drosophila
melanogaster, the zebrafish Brachydanio
rerio, the mouse Mus
musculus, and the weed Arabidopsis
thaliana.
Physiological
Physiology studies the mechanical, physical, and biochemical processes of living organisms by attempting to understand how all of the structures function as a whole. The theme of "structure to function" is central to biology. Physiological studies have traditionally been divided into plant physiology and animal physiology, but the principles of physiology are universal, no matter what particular organism is being studied. For example, what is learned about the physiology of yeast cells can also apply to human cells. The field of animal physiology extends the tools and methods of human physiology to non-human species. Plant physiology also borrows techniques from both fields.Anatomy is an
important branch of physiology and considers how organ
systems in animals, such as the nervous,
immune,
endocrine,
respiratory,
and circulatory
systems, function and interact. The study of these systems is
shared with medically
oriented disciplines such as neurology and immunology.
Evolution
Evolution is concerned with the origin and
descent of species, as
well as their change over time, and includes scientists from many
taxonomically-oriented
disciplines. For example, it generally involves scientists who have
special training in particular organisms such as mammalogy, ornithology, botany, or herpetology, but use those
organisms as systems to answer general questions about evolution.
Evolutionary biology is mainly based on paleontology, which uses
the fossil record to
answer questions about the mode and tempo of evolution, as well as
the developments in areas such as population
genetics and evolutionary theory. In the 1980s, developmental
biology re-entered evolutionary biology from its initial
exclusion from the modern synthesis through the study of
evolutionary developmental biology. Related fields which are
often considered part of evolutionary biology are phylogenetics, systematics, and taxonomy.
Up into the 19th
century, it was believed that life forms were being
continuously created under certain conditions (see
spontaneous generation). This misconception was challenged by
William
Harvey's diction that "all life [is] from [an] egg" (from the
Latin
"Omne
vivum ex ovo"), a foundational concept of modern biology. It
simply means that there is an unbroken continuity of life from its
initial origin to the present time.
A group of organisms shares a common descent if
they share a common ancestor. All organisms on the Earth have been and
are descended from a common ancestor or an ancestral gene pool. This
last universal common ancestor of all organisms is believed to have
appeared about 3.5
billion years ago. Biologists generally regard the universality
of the genetic code
as definitive evidence in favor of the theory of universal common
descent (UCD) for all bacteria, archaea, and eukaryotes (see: origin of
life).
The two major traditional taxonomically-oriented
disciplines are botany
and zoology. Botany is
the scientific study of plants. Botany covers a wide range
of scientific disciplines that study the growth,
reproduction,
metabolism, development, diseases, and evolution of plant life.
Zoology involves the study of animals, including the study of
their physiology
within the fields of anatomy and embryology. The common
genetic and
developmental mechanisms of animals and plants is studied in
molecular
biology, molecular
genetics, and developmental
biology. The ecology
of animals is covered under behavioral
ecology and other fields.
However, many scientists now consider this
five-kingdom system to be outdated. Modern alternative
classification systems generally begin with the three-domain
system:
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:
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 or underlined. 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:
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). A fourth
Draft BioCode was published in 1997 in an attempt to standardize
naming in these three areas, but it has yet to be formally adopted.
The Virus
International Code of Virus Classification and Nomenclature
(ICVCN) remains outside the BioCode.
Environmental
Ecology studies the distribution and abundance of living organisms, and the interactions between organisms and their environment. The environment of an organism includes both its habitat, which can be described as the sum of local abiotic factors such as climate and ecology, as well as the other organisms that share its habitat. Ecological systems are studied at several different levels, from individuals and populations to ecosystems and the biosphere. As can be surmised, ecology is a science that draws on several disciplines.Ethology studies
animal behavior (particularly of
social animals such as primates and canids), and is sometimes
considered a branch of zoology. Ethologists have been
particularly concerned with the evolution of behavior and the
understanding of behavior in terms of the theory of natural
selection. In one sense, the first modern ethologist was
Charles
Darwin, whose book "The
Expression of the Emotions in Man and Animals" influenced many
ethologists.
Biogeography
studies the spatial distribution of organisms on the Earth, focusing on
topics like plate
tectonics, climate
change, dispersal and migration, and cladistics.
Every living thing interacts with other organisms
and its environment.
One reason that biological systems can be difficult to study is
that so many different interactions with other organisms and the
environment are possible, even on the smallest of scales. A
microscopic bacterium
responding to a local sugar gradient is responding to its
environment as much as a lion is responding to its
environment when it searches for food in the African savannah. For any given species,
behaviors can be
co-operative,
aggressive, parasitic or symbiotic. Matters become more
complex when two or more different species interact in an ecosystem. Studies of this
type are the province of ecology.
History
Although the concept of biology as a single coherent field arose in the 19th century, the biological sciences emerged from traditions of medicine and natural history reaching back to Galen and Aristotle in the ancient Greco-Roman world, which were then further developed in the Middle Ages by Muslim physicians such as al-Jahiz, Avicenna, Avenzoar and Ibn al-Nafis. During the European Renaissance and early modern period, biological thought was revolutionized in Europe by a renewed interest in empiricism and the discovery of many novel organisms. Prominent in this movement were Vesalius and Harvey, who used experimentation and careful observation in physiology, and naturalists such as Linnaeus and Buffon who began to classify the diversity of life and the fossil record, as well as the development and behavior of organisms. Microscopy revealed the previously unknown world of microorganisms, laying the groundwork for cell theory. The growing importance of natural theology, partly a response to the rise of mechanical philosophy, encouraged the growth of natural history.Over the 18th and 19th centuries, biological
sciences such as botany
and zoology became
increasingly professional scientific
disciplines. Lavoisier and
other physical scientists began to connect the animate and
inanimate worlds through physics and chemistry.
Explorer-naturalists such as Alexander
von Humboldt investigated the interaction between organisms and
their environment, and the ways this relationship depends on
geography—laying the foundations for biogeography, ecology and ethology. Naturalists began to
reject essentialism
and consider the importance of extinction and the
mutability of species. Cell theory
provided a new perspective on the fundamental basis of life. These
developments, as well as the results from embryology and paleontology, were
synthesized in aps Charles
Darwins theory of evolution by natural
selection. The end of the 19th century saw the fall of spontaneous
generation and the rise of the germ
theory of disease, though the mechanism of inheritance
remained a mystery.
References
Further reading
- Molecular Biology of the Cell
- Ecology: From Individuals to Ecosystems
- Why Big Fierce Animals are Rare: An Ecologist's Perspective
- On Becoming a Biologist
- Biology, Visualizing Life
External links
- Location guide to original research materials in biology - the papers of prominent biologists in history
- OSU's Phylocode
- The Tree of Life: A multi-authored, distributed Internet project containing information about phylogeny and biodiversity.
- MIT video lecture series on biology
- Biology and Bioethics.
Journal links
- PLos Biology A peer-reviewed, open-access journal published by the Public Library of Science
- International Journal of Biological Sciences A biological journal publishes peer-reviewed scientific papers of significance
- Perspectives in Biology and Medicine
biology in Afrikaans: Biologie
biology in Tosk Albanian: Biologie
biology in Amharic: ሥነ ሕይወት
biology in Arabic: علم الأحياء
biology in Aragonese: Biolochía
biology in Aromanian: Biologhia
biology in Franco-Provençal: Biologia
biology in Asturian: Bioloxía
biology in Azerbaijani: Biologiya
biology in Bengali: জীববিজ্ঞান
biology in Min Nan: Seng-bu̍t-ha̍k
biology in Banyumasan: Biologi
biology in Bashkir: Биология
biology in Belarusian (Tarashkevitsa):
Біялёгія
biology in Bavarian: Biologie
biology in Bosnian: Biologija
biology in Breton: Bevoniezh
biology in Bulgarian: Биология
biology in Catalan: Biologia
biology in Chuvash: Биологи
biology in Czech: Biologie
biology in Chamorro: Bioloyia
biology in Corsican: Biologia
biology in Welsh: Bioleg
biology in Danish: Biologi
biology in German: Biologie
biology in Dhivehi: ދިރުމާބެހޭ އިލްމު
biology in Estonian: Bioloogia
biology in Modern Greek (1453-): Βιολογία
biology in Erzya:
Биологиясь-эриеньсодамось
biology in Spanish: Biología
biology in Esperanto: Biologio
biology in Basque: Biologia
biology in Extremaduran: Biulohia
biology in Persian: زیستشناسی
biology in Faroese: Lívfrøði
biology in French: Biologie
biology in Western Frisian: Biology
biology in Friulian: Biologjie
biology in Irish: Bitheolaíocht
biology in Gan Chinese: 生物學
biology in Manx: Bea-oaylleeaght
biology in Scottish Gaelic: Bith-eòlas
biology in Galician: Bioloxía
biology in Classical Chinese: 生物學
biology in Hakka Chinese: Sâng-vu̍t-ho̍k
biology in Kalmyk: Биолог
biology in Korean: 생물학
biology in Hindi: जीव विज्ञान
biology in Upper Sorbian: Biologija
biology in Croatian: Biologija
biology in Ido: Biologio
biology in Indonesian: Biologi
biology in Interlingua (International Auxiliary
Language Association): Biologia
biology in Interlingue: Biologie
biology in Inuktitut:
ᐆᒪᔅᓱᓯᖃᕐᑐᓕᕆᓂᖅ/umasusirkartuliriniq
biology in Ossetian: Биологи
biology in Xhosa: IBayoloji
biology in Icelandic: Líffræði
biology in Italian: Biologia
biology in Hebrew: ביולוגיה
biology in Javanese: Biologi
biology in Kalaallisut:
Uumassuseqartulerineq
biology in Pampanga: Biologia
biology in Kannada: ಜೀವಶಾಸ್ತ್ರ
biology in Kara-Kalpak: Biologiya
biology in Georgian: ბიოლოგია
biology in Kashmiri: علم حیاتیات
biology in Kashubian: Biologijô
biology in Cornish: Bywonieth
biology in Kirghiz: Биология
biology in Swahili (macrolanguage):
Biolojia
biology in Haitian: Biyoloji
biology in Ladino: Biolojiya
biology in Lao: ຊີວະສາດ
biology in Latin: Biologia
biology in Latvian: Bioloģija
biology in Luxembourgish: Biologie
biology in Lithuanian: Biologija
biology in Limburgan: Biologie
biology in Lojban: mivyske
biology in Lombard: Biulugía
biology in Hungarian: Biológia
biology in Macedonian: Биологија
biology in Malayalam: ജീവശാസ്ത്രം
biology in Maltese: Bijoloġija
biology in Malay (macrolanguage): Biologi
biology in Mongolian: Биологи
nah:Yōlizmatiliztli
biology in Dutch: Biologie
biology in Dutch Low Saxon: Biologie
biology in Nepali: जीवशास्त्र
biology in Japanese: 生物学
biology in Neapolitan: Biologgia
biology in Pitcairn-Norfolk: Biiolojii
biology in Norwegian: Biologi
biology in Norwegian Nynorsk: Biologi
biology in Narom: Biologie
biology in Novial: Biologia
biology in Occitan (post 1500): Biologia
biology in Uzbek: Biologiya
biology in Pushto: ژواکپوهنه
biology in Central Khmer: ជីវវិទ្យា
biology in Low German: Biologie
biology in Polish: Biologia
biology in Portuguese: Biologia
biology in Romanian: Biologie
biology in Quechua: Kawsay yachay
biology in Russian: Биология
biology in Samoan: Paiolo
biology in Sanskrit: जीवशास्त्रं
biology in Sardinian: Biologia
biology in Scots: Biology
biology in Albanian: Biologjia
biology in Sicilian: Bioluggìa
biology in Simple English: Biology
biology in Swati: Ibhayoloji
biology in Slovak: Biológia
biology in Slovenian: Biologija
biology in Somali: Bayoloji
biology in Serbian: Биологија
biology in Serbo-Croatian: Biologija
biology in Saterfriesisch: Biologie
biology in Sundanese: Biologi
biology in Finnish: Biologia
biology in Swedish: Biologi
biology in Tagalog: Biyolohiya
biology in Tamil: உயிரியல்
biology in Tatar: Biologí
biology in Telugu: జీవ శాస్త్రము
biology in Thai: ชีววิทยา
biology in Vietnamese: Sinh học
biology in Tigrinya: ባዮሎጂ
biology in Tajik: Биология
biology in Turkish: Biyoloji
biology in Buginese: ᨅᨗᨕᨚᨒᨚᨁᨗ
biology in Ukrainian: Біологія
biology in Urdu: حیاتیات
biology in Venetian: Biołogia
biology in Volapük: Lifav
biology in Võro: Bioloogia
biology in Waray (Philippines): Biyolohiya
biology in Yiddish: ביאלאגיע
biology in Contenese: 生物學
biology in Dimli: Biyolociye
biology in Zeeuws: Biologie
biology in Samogitian: Bioluogėjė
biology in Chinese: 生物学
Synonyms, Antonyms and Related Words
aerobiology, agrobiology, anatomy, animal physiology,
anthropology,
astrobiology,
bacteriology,
biochemics, biochemistry, biochemy, bioecology, biological
science, biometrics,
biometry, bionics, bionomics, biophysics, botany, cell physiology,
comparative anatomy, conchology, cryobiology, cybernetics, cytology, ecology, electrobiology, embryology, entomology, enzymology, ethnobiology, ethology, exobiology, genetics, gnotobiotics, helminthology, herpetology, ichthyology, life science,
malacology, mammalogy, microbiology, molecular
biology, ornithology, pharmacology, physiology, protozoology, radiobiology, taxidermy, taxonomy, virology, xenobiology, zoogeography, zoography, zoology, zoonomy, zoopathology, zoophysics, zootaxy, zootomy