The branches of science, also referred to as sciences, scientific fields or scientific disciplines, are commonly divided into three major groups: * Formal sciences: the study of formal systems, such as those under the branches of logic and mathematics, which use an ''

a priori ("from the earlier") and ("from the later") are Latin phrases used in philosophy to distinguish types of knowledge, justification, or argument by their reliance on empirical evidence or experience. knowledge is independent from current ex ...

'', as opposed to

empirical Empirical evidence for a proposition is evidence, i.e. what supports or counters this proposition, that is constituted by or accessible to sense experience or experimental procedure. Empirical evidence is of central importance to the sciences and ...

, methodology. * Natural sciences: the study of natural phenomena (including

cosmological Cosmology () is a branch of physics and metaphysics dealing with the nature of the universe. The term ''cosmology'' was first used in English in 1656 in Thomas Blount's ''Glossographia'', and in 1731 taken up in Latin by German philosopher ...

, geological,

physical Physical may refer to: * Physical examination, a regular overall check-up with a doctor * ''Physical'' (Olivia Newton-John album), 1981 ** "Physical" (Olivia Newton-John song) * ''Physical'' (Gabe Gurnsey album) * "Physical" (Alcazar song) (2004) * ...

, chemical, and

biological Biology is the scientific study of life. It is a natural science with a broad scope but has several unifying themes that tie it together as a single, coherent field. For instance, all organisms are made up of cells that process hereditary in ...

factors of the universe). Natural science can be divided into two main branches:

physical science Physical science is a branch of natural science that studies non-living systems, in contrast to life science. It in turn has many branches, each referred to as a "physical science", together called the "physical sciences". Definition Physi ...

and

life science Life is a quality that distinguishes matter that has biological processes, such as signaling and self-sustaining processes, from that which does not, and is defined by the capacity for growth, reaction to stimuli, metabolism, energy trans ...

(or

biology Biology is the scientific study of life. It is a natural science with a broad scope but has several unifying themes that tie it together as a single, coherent field. For instance, all organisms are made up of cells that process hereditary ...

). * Social sciences: the study of human behavior in its social and cultural aspects.

Scientific Science is a systematic endeavor that builds and organizes knowledge in the form of testable explanations and predictions about the universe. Science may be as old as the human species, and some of the earliest archeological evidence f ...

knowledge must be based on observable phenomena and must be capable of being verified by other researchers working under the same conditions. This verifiability may well vary even ''within'' a scientific discipline. Natural, social, and formal science make up the

fundamental science Basic research, also called pure research or fundamental research, is a type of scientific research with the aim of improving scientific theories for better understanding and prediction of natural or other phenomena. In contrast, applied researc ...

s, which form the basis of interdisciplinarity- and

applied science Applied science is the use of the scientific method and knowledge obtained via conclusions from the method to attain practical goals. It includes a broad range of disciplines such as engineering and medicine. Applied science is often contrasted ...

s such as engineering and medicine. Specialized scientific disciplines that exist in multiple categories may include parts of other scientific disciplines but often possess their own terminologies and expertises.

Formal sciences

The ''formal sciences'' are the branches of science that are concerned with formal systems, such as logic, mathematics,

theoretical computer science computer science (TCS) is a subset of general computer science and mathematics that focuses on mathematical aspects of computer science such as the theory of computation, lambda calculus, and type theory. It is difficult to circumscribe the ...

, information theory, systems theory,

decision theory Decision theory (or the theory of choice; not to be confused with choice theory) is a branch of applied probability theory concerned with the theory of making decisions based on assigning probabilities to various factors and assigning numerical ...

, statistics. Unlike other branches, the formal sciences are not concerned with the validity of theories based on

observation Observation is the active acquisition of information from a primary source. In living beings, observation employs the senses. In science, observation can also involve the perception and recording of data via the use of scientific instruments. Th ...

s in the real world (

empirical knowledge Empirical evidence for a proposition is evidence, i.e. what supports or counters this proposition, that is constituted by or accessible to sense experience or experimental procedure. Empirical evidence is of central importance to the sciences and ...

), but rather with the properties of formal systems based on

definition A definition is a statement of the meaning of a term (a word, phrase, or other set of symbols). Definitions can be classified into two large categories: intensional definitions (which try to give the sense of a term), and extensional definiti ...

s and

rule Rule or ruling may refer to: Education * Royal University of Law and Economics (RULE), a university in Cambodia Human activity * The exercise of political or personal control by someone with authority or power * Business rule, a rule pert ...

s. Hence there is disagreement on whether the formal sciences actually constitute a science. Methods of the formal sciences are, however, essential to the construction and testing of scientific models dealing with observable reality, and major advances in formal sciences have often enabled major advances in the empirical sciences.

Logic

''Logic'' (from Greek: grc, λογική, label=none, lit=possessed of reason, intellectual,

dialectical Dialectic ( grc-gre, διαλεκτική, ''dialektikḗ''; related to dialogue; german: Dialektik), also known as the dialectical method, is a discourse between two or more people holding different points of view about a subject but wishing t ...

argument An argument is a statement or group of statements called premises intended to determine the degree of truth or acceptability of another statement called conclusion. Arguments can be studied from three main perspectives: the logical, the dialectic ...

ative, translit=logikḗ) is the systematic study of valid

rules of inference In the philosophy of logic, a rule of inference, inference rule or transformation rule is a logical form consisting of a function which takes premises, analyzes their syntax, and returns a conclusion (or conclusions). For example, the rule of in ...

, i.e. the relations that lead to the acceptance of one proposition (the conclusion) on the basis of a set of other propositions (

premise A premise or premiss is a true or false statement that helps form the body of an argument, which logically leads to a true or false conclusion. A premise makes a declarative statement about its subject matter which enables a reader to either agre ...

s). More broadly, logic is the analysis and appraisal of

s. It has traditionally included the classification of arguments; the systematic exposition of the logical forms; the validity and soundness of deductive reasoning; the strength of inductive reasoning; the study of formal proofs and inference (including

paradox A paradox is a logically self-contradictory statement or a statement that runs contrary to one's expectation. It is a statement that, despite apparently valid reasoning from true premises, leads to a seemingly self-contradictory or a logically u ...

es and fallacies); and the study of syntax and semantics. Historically, logic has been studied in philosophy (since ancient times) and mathematics (since the mid-19th century). More recently, logic has been studied in cognitive science, which draws on computer science, linguistics, philosophy and psychology, among other disciplines.

Data Science

Information Science

Mathematics

''Mathematics'', in the broadest sense, is just a synonym of formal science; but traditionally mathematics means more specifically the coalition of four areas:

arithmetic Arithmetic () is an elementary part of mathematics that consists of the study of the properties of the traditional operations on numbers—addition, subtraction, multiplication, division, exponentiation, and extraction of roots. In the 19th c ...

algebra Algebra () is one of the broad areas of mathematics. Roughly speaking, algebra is the study of mathematical symbols and the rules for manipulating these symbols in formulas; it is a unifying thread of almost all of mathematics. Elementary a ...

, geometry, and

analysis Analysis ( : analyses) is the process of breaking a complex topic or substance into smaller parts in order to gain a better understanding of it. The technique has been applied in the study of mathematics and logic since before Aristotle (3 ...

, which are, to some degree, the study of quantity, structure, space, and change respectively.

Statistics

''Statistics'' is the study of the collection, organization, and interpretation of data.Dodge, Y. (2003) ''The Oxford Dictionary of Statistical Terms'', OUP. It deals with all aspects of this, including the planning of data collection in terms of the design of surveys and experiments. A statistician is someone who is particularly well versed in the ways of thinking necessary for the successful application of statistical analysis. Such people have often gained this experience through working in any of a wide number of fields. There is also a discipline called ''

mathematical statistics Mathematical statistics is the application of probability theory, a branch of mathematics, to statistics, as opposed to techniques for collecting statistical data. Specific mathematical techniques which are used for this include mathematical a ...

'', which is concerned with the theoretical basis of the subject. The word ''statistics'', when referring to the scientific discipline, is singular, as in "Statistics is an art." This should not be confused with the word ''statistic'', referring to a quantity (such as mean or median) calculated from a set of data, whose plural is ''statistics'' ("this statistic seems wrong" or "these statistics are misleading").

Systems theory

''Systems theory'' is the transdisciplinary study of systems in general, to elucidate principles that can be applied to all types of systems in all fields of research. The term does not yet have a well-established, precise meaning, but systems theory can reasonably be considered a specialization of

systems thinking Systems thinking is a way of making sense of the complexity of the world by looking at it in terms of wholes and relationships rather than by splitting it down into its parts. It has been used as a way of exploring and developing effective actio ...

and a generalization of systems science. The term originates from Bertalanffy's General System Theory (GST) and is used in later efforts in other fields, such as the action theory of Talcott Parsons and the sociological

autopoiesis The term autopoiesis () refers to a system capable of producing and maintaining itself by creating its own parts. The term was introduced in the 1972 publication '' Autopoiesis and Cognition: The Realization of the Living'' by Chilean biologists ...

Niklas Luhmann Niklas Luhmann (; ; December 8, 1927 – November 6, 1998) was a German sociologist, philosopher of social science, and a prominent thinker in systems theory. Biography Luhmann was born in Lüneburg, Free State of Prussia, where his father's ...

. In this context the word ''systems'' is used to refer specifically to self-regulating systems, i.e. that are self-correcting through

feedback Feedback occurs when outputs of a system are routed back as inputs as part of a chain of cause-and-effect that forms a circuit or loop. The system can then be said to ''feed back'' into itself. The notion of cause-and-effect has to be handled c ...

. Self-regulating systems are found in nature, including the physiological systems of our body, in local and global ecosystems, and climate.

Decision theory

''Decision theory'' (or the ''theory of choice'' not to be confused with choice theory) is the study of an agent's choices. Decision theory can be broken into two branches:

normative Normative generally means relating to an evaluative standard. Normativity is the phenomenon in human societies of designating some actions or outcomes as good, desirable, or permissible, and others as bad, undesirable, or impermissible. A norm in ...

decision theory, which analyzes the outcomes of decisions or determines the

optimal decision An optimal decision is a decision that leads to at least as good a known or expected outcome as all other available decision options. It is an important concept in decision theory. In order to compare the different decision outcomes, one commonly ...

s given constraints and assumptions, and descriptive decision theory, which analyzes ''how'' agents actually make the decisions they do. Decision theory is closely related to the field of

game theory Game theory is the study of mathematical models of strategic interactions among rational agents. Myerson, Roger B. (1991). ''Game Theory: Analysis of Conflict,'' Harvard University Press, p.&nbs1 Chapter-preview links, ppvii–xi It has applic ...

and is an interdisciplinary topic, studied by economists, statisticians, psychologists, biologists, political and other social scientists, philosophers, and computer scientists. Empirical applications of this rich theory are usually done with the help of statistical and econometric methods.

Theoretical computer science

''Theoretical computer science'' (''TCS'') is a subset of general computer science and mathematics that focuses on more mathematical topics of computing, and includes the

theory of computation In theoretical computer science and mathematics, the theory of computation is the branch that deals with what problems can be solved on a model of computation, using an algorithm, how efficiently they can be solved or to what degree (e.g., ...

. It is difficult to circumscribe the theoretical areas precisely. The ACM's Special Interest Group on Algorithms and Computation Theory (SIGACT) provides the following description:

Natural sciences

''Natural science'' is a branch of science concerned with the description, prediction, and understanding of

natural phenomena Nature, in the broadest sense, is the physical world or universe. "Nature" can refer to the phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. Although humans are p ...

, based on empirical evidence from

and experimentation. Mechanisms such as peer review and repeatability of findings are used to try to ensure the validity of scientific advances. Natural science can be divided into two main branches:

and

. Life science is alternatively known as

, and physical science is subdivided into branches: physics, chemistry,

astronomy Astronomy () is a natural science that studies celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and evolution. Objects of interest include planets, moons, stars, nebulae, galax ...

and Earth science. These branches of natural science may be further divided into more specialized branches (also known as fields)

Physical science

''Physical science'' is an encompassing term for the branches of natural science that study non-living systems, in contrast to the life sciences. However, the term "physical" creates an unintended, somewhat arbitrary distinction, since many branches of physical science also study biological phenomena. There is a difference between physical science and physics.

Physics

''Physics'' (from grc, φύσις,

physis Fusis, Phusis or Physis (; grc, φύσις ) is a Greek philosophical, theological, and scientific term, usually translated into English—according to its Latin translation "natura"—as "nature". The term originated in ancient Greek philosophy, ...

, nature) is a natural science that involves the study of

matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects that can be touched are ultimately composed of atoms, which are made up of interacting subatomic parti ...

and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of

nature Nature, in the broadest sense, is the physical world or universe. "Nature" can refer to the phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. Although humans are p ...

, conducted in order to understand how the universe behaves. Physics is one of the oldest

academic discipline An academy (Attic Greek: Ἀκαδήμεια; Koine Greek Ἀκαδημία) is an institution of secondary or tertiary higher learning (and generally also research or honorary membership). The name traces back to Plato's school of philosophy, f ...

s, perhaps the oldest through its inclusion of

. Over the last two millennia, physics was a part of natural philosophy along with chemistry, certain branches of mathematics, and

, but during the

Scientific Revolution The Scientific Revolution was a series of events that marked the emergence of modern science during the early modern period, when developments in mathematics, physics, astronomy, biology (including human anatomy) and chemistry transforme ...

in the 16th century, the natural sciences emerged as unique research programs in their own right. Certain research areas are interdisciplinary, such as

biophysics Biophysics is an interdisciplinary science that applies approaches and methods traditionally used in physics to study biological phenomena. Biophysics covers all scales of biological organization, from molecular to organismic and populations. ...

and

quantum chemistry Quantum chemistry, also called molecular quantum mechanics, is a branch of physical chemistry focused on the application of quantum mechanics to chemical systems, particularly towards the quantum-mechanical calculation of electronic contributions ...

, which means that the boundaries of physics are not rigidly defined. In the nineteenth and twentieth centuries physicalism emerged as a major unifying feature of the philosophy of science as physics provides fundamental explanations for every

observed Observation is the active acquisition of information from a primary source. In living beings, observation employs the senses. In science, observation can also involve the perception and recording of data via the use of scientific instruments. The ...

natural phenomenon. New ideas in physics often explain the fundamental mechanisms of other sciences, while opening to new research areas in mathematics and philosophy.

Chemistry

''Chemistry'' (the etymology of the word has been much disputed) is the science of

and the changes it undergoes. The science of matter is also addressed by physics, but while physics takes a more general and fundamental approach, chemistry is more specialized, being concerned by the composition, behavior (or reaction), structure, and properties of

, as well as the changes it undergoes during

chemical reaction A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breakin ...

s. It is a

which studies various substances, atoms, molecules, and matter (especially carbon based). Example sub-disciplines of chemistry include:

biochemistry Biochemistry or biological chemistry is the study of chemical processes within and relating to living organisms. A sub-discipline of both chemistry and biology, biochemistry may be divided into three fields: structural biology, enzymology and ...

, the study of substances found in

biological organism In biology, an organism () is any living system that functions as an individual entity. All organisms are composed of cells (cell theory). Organisms are classified by taxonomy into groups such as multicellular animals, plants, and fungi ...

physical chemistry Physical chemistry is the study of macroscopic and microscopic phenomena in chemical systems in terms of the principles, practices, and concepts of physics such as motion, energy, force, time, thermodynamics, quantum chemistry, statistical me ...

, the study of chemical processes using physical concepts such as thermodynamics and quantum mechanics; and analytical chemistry, the analysis of material samples to gain an understanding of their

chemical composition A chemical composition specifies the identity, arrangement, and ratio of the elements making up a compound. Chemical formulas can be used to describe the relative amounts of elements present in a compound. For example, the chemical formula for ...

and structure. Many more specialized disciplines have emerged in recent years, e.g.

neurochemistry Neurochemistry is the study of chemicals, including neurotransmitters and other molecules such as psychopharmaceuticals and neuropeptides, that control and influence the physiology of the nervous system. This particular field within neuroscienc ...

the chemical study of the nervous system.

Earth science

''Earth science'' (also known as ''geoscience'', ''the geosciences'' or ''the Earth sciences'') is an all-embracing term for the sciences related to the planet Earth. It is arguably a special case in planetary science, the Earth being the only known life-bearing planet. There are both reductionist and holistic approaches to Earth sciences. The formal discipline of Earth sciences may include the study of the

atmosphere An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A s ...

hydrosphere The hydrosphere () is the combined mass of water found on, under, and above the surface of a planet, minor planet, or natural satellite. Although Earth's hydrosphere has been around for about 4 billion years, it continues to change in shape. This ...

, lithosphere, and

biosphere The biosphere (from Greek βίος ''bíos'' "life" and σφαῖρα ''sphaira'' "sphere"), also known as the ecosphere (from Greek οἶκος ''oîkos'' "environment" and σφαῖρα), is the worldwide sum of all ecosystems. It can also be ...

, as well as the solid earth. Typically Earth scientists will use tools from physics, chemistry,

, geography,

chronology Chronology (from Latin ''chronologia'', from Ancient Greek , ''chrónos'', "time"; and , ''-logia'') is the science of arranging events in their order of occurrence in time. Consider, for example, the use of a timeline or sequence of events. I ...

and mathematics to build a quantitative understanding of how the Earth system works, and how it evolved to its current state.

= Geology

= ''Geology'' (from the Ancient Greek γῆ, ''gē'' ("earth") and -λoγία, ''-logia'', ("study of", "discourse")) is an Earth science concerned with the solid Earth, the

rocks In geology, rock (or stone) is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its chemical composition, and the way in which it is formed. Rocks form the Earth's o ...

of which it is composed, and the processes by which they change over time. Geology can also include the study of the solid features of any terrestrial planet or natural satellite such as Mars or the Moon. Modern geology significantly overlaps all other Earth sciences, including hydrology and the

atmospheric sciences Atmospheric science is the study of the Earth's atmosphere and its various inner-working physical processes. Meteorology includes atmospheric chemistry and atmospheric physics with a major focus on weather forecasting. Climatology is the study ...

, and so is treated as one major aspect of integrated

Earth system science Earth system science (ESS) is the application of systems science to the Earth. In particular, it considers interactions and 'feedbacks', through material and energy fluxes, between the Earth's sub-systems' cycles, processes and "spheres"—atmos ...

and planetary science.

= Oceanography

= ''Oceanography'', or ''marine science'', is the branch of Earth science that studies the ocean. It covers a wide range of topics, including

marine organisms Marine life, sea life, or ocean life is the plants, animals and other organisms that live in the salt water of seas or oceans, or the brackish water of coastal estuaries. At a fundamental level, marine life affects the nature of the planet. ...

and ecosystem dynamics; ocean currents,

waves Waves most often refers to: * Waves, oscillations accompanied by a transfer of energy that travel through space or mass. * Wind waves, surface waves that occur on the free surface of bodies of water. Waves may also refer to: Music *Waves (ban ...

, and geophysical fluid dynamics; plate tectonics and the geology of the seafloor; and fluxes of various chemical substances and physical properties within the ocean and across its boundaries. These diverse topics reflect multiple disciplines that oceanographers blend to further knowledge of the world ocean and understanding of processes within it:

, chemistry, geology,

meteorology Meteorology is a branch of the atmospheric sciences (which include atmospheric chemistry and physics) with a major focus on weather forecasting. The study of meteorology dates back millennia, though significant progress in meteorology did not ...

, and physics as well as geography.

= Meteorology

= ''Meteorology'' is the interdisciplinary scientific study of the

. Studies in the field stretch back millennia, though significant progress in meteorology did not occur until the 17th century. The 19th century saw breakthroughs occur after observing networks developed across several countries. After the development of the computer in the latter half of the 20th century, breakthroughs in weather forecasting were achieved.

Astronomy

''Space science'' is the study of everything in outer space. This has sometimes been called

, but recently astronomy has come to be regarded as a division of broader space science, which has grown to include other related fields, such as studying issues related to space travel and space exploration (including

space medicine Space medicine is the practice of medicine on astronauts in outer space whereas astronautical hygiene is the application of science and technology to the prevention or control of exposure to the hazards that may cause astronaut ill health. Bot ...

space archaeology In archaeology, space archaeology is the research-based study of various human-made items found in space, their interpretation as clues to the adventures humanity has experienced in space, and their preservation as cultural heritage. It includes ...

and science performed in outer space (see ''

space research Space research is scientific study carried out in outer space, and by studying outer space. From the use of space technology to the observable universe, space research is a wide research field. Earth science, materials science, biology, medi ...

'').

Biology

''Life science'', also known as ''biology'', is the natural science that studies life such as microorganisms, plants, and

animal Animals are multicellular, eukaryotic organisms in the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen, are able to move, can reproduce sexually, and go through an ontogenetic stage in ...

s including human beings, – including their physical structure,

chemical processes A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemical substance cannot be separated into its constituent elements by physical separation methods, i.e., wit ...

, molecular interactions, physiological mechanisms,

development Development or developing may refer to: Arts *Development hell, when a project is stuck in development *Filmmaking, development phase, including finance and budgeting *Development (music), the process thematic material is reshaped *Photographi ...

, and evolution.Based on definition from: Despite the complexity of the science, certain unifying concepts consolidate it into a single, coherent field. Biology recognizes the

cell Cell most often refers to: * Cell (biology), the functional basic unit of life Cell may also refer to: Locations * Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery w ...

as the basic unit of life, genes as the basic unit of heredity, and evolution as the engine that propels the

creation Creation may refer to: Religion *''Creatio ex nihilo'', the concept that matter was created by God out of nothing *Creation myth, a religious story of the origin of the world and how people first came to inhabit it *Creationism, the belief that ...

and extinction of

species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...

Living organisms In biology, an organism () is any living system that functions as an individual entity. All organisms are composed of cells (cell theory). Organisms are classified by taxonomy into groups such as multicellular animals, plants, and fun ...

are open systems that survive by transforming energy and decreasing their local entropy to maintain a stable and vital condition defined as

homeostasis In biology, homeostasis (British also homoeostasis) (/hɒmɪə(ʊ)ˈsteɪsɪs/) is the state of steady internal, physical, and chemical conditions maintained by living systems. This is the condition of optimal functioning for the organism and i ...

Biochemistry

''Biochemistry'', or ''biological chemistry'', is the study of

chemical process In a scientific sense, a chemical process is a method or means of somehow changing one or more chemicals or chemical compounds. Such a chemical process can occur by itself or be caused by an outside force, and involves a chemical reaction of som ...

es within and relating to living organisms. It is a sub-discipline of both biology and chemistry, and from a reductionist point of view it is fundamental in biology. Biochemistry is closely related to molecular biology,

cell biology Cell biology (also cellular biology or cytology) is a branch of biology that studies the structure, function, and behavior of cells. All living organisms are made of cells. A cell is the basic unit of life that is responsible for the living a ...

, genetics, and physiology.

Microbiology

''Microbiology'' is the study of microorganisms, those being unicellular (single cell),

multicellular A multicellular organism is an organism that consists of more than one cell, in contrast to unicellular organism. All species of animals, land plants and most fungi are multicellular, as are many algae, whereas a few organisms are partially uni ...

(cell colony), or

acellular Non-cellular life, or acellular life is life that exists without a cellular structure for at least part of its life cycle. Historically, most (descriptive) definitions of life postulated that an organism must be composed of one or more cells, ...

(lacking cells). Microbiology encompasses numerous sub-disciplines including virology,

bacteriology Bacteriology is the branch and specialty of biology that studies the morphology, ecology, genetics and biochemistry of bacteria as well as many other aspects related to them. This subdivision of microbiology involves the identification, classificat ...

protistology Protistology is a scientific discipline devoted to the study of protists, a highly diverse group of eukaryotic organisms. All eukaryotes apart from animals, plants and fungi are considered protists. Its field of study therefore overlaps with the ...

, mycology,

immunology Immunology is a branch of medicineImmunology for Medical Students, Roderick Nairn, Matthew Helbert, Mosby, 2007 and biology that covers the medical study of immune systems in humans, animals, plants and sapient species. In such we can see ther ...

and parasitology.

Botany

''Botany'', also called ''plant science(s)'', ''plant biology'' or ''phytology'', is the science of plant life and a branch of

. Traditionally, botany has also included the study of fungi and

algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthesis, photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from u ...

by mycologists and phycologists respectively, with the study of these three groups of organisms remaining within the sphere of interest of the

International Botanical Congress International Botanical Congress (IBC) is an international meeting of botanists in all scientific fields, authorized by the International Association of Botanical and Mycological Societies (IABMS) and held every six years, with the location rotati ...

. Nowadays, botanists (in the strict sense) study approximately 410,000

land plants The Embryophyta (), or land plants, are the most familiar group of green plants that comprise vegetation on Earth. Embryophytes () have a common ancestor with green algae, having emerged within the Phragmoplastophyta clade of green algae as siste ...

of which some 391,000 species are vascular plants (including approximately 369,000 species of flowering plants), and approximately 20,000 are

bryophyte The Bryophyta s.l. are a proposed taxonomic division containing three groups of non-vascular land plants (embryophytes): the liverworts, hornworts and mosses. Bryophyta s.s. consists of the mosses only. They are characteristically limited in s ...

Zoology

''Zoology'' () is the branch of

that studies the animal kingdom, including the structure,

embryology Embryology (from Greek ἔμβρυον, ''embryon'', "the unborn, embryo"; and -λογία, ''-logia'') is the branch of animal biology that studies the prenatal development of gametes (sex cells), fertilization, and development of embryos an ...

, evolution,

classification Classification is a process related to categorization, the process in which ideas and objects are recognized, differentiated and understood. Classification is the grouping of related facts into classes. It may also refer to: Business, organizat ...

habits A habit (or wont as a humorous and formal term) is a routine of behavior that is repeated regularly and tends to occur subconsciously.

, and distribution of all

s, both living and extinct, and how they interact with their ecosystems. The term is derived from Ancient Greek ζῷον, ''zōion'', i.e. "

" and λόγος, ''logos'', i.e. "knowledge, study". Some branches of zoology include: anthrozoology,

arachnology Arachnology is the scientific study of arachnids, which comprise spiders and related invertebrates such as scorpions, pseudoscorpions, and harvestmen. Those who study spiders and other arachnids are arachnologists. More narrowly, the study of ...

archaeozoology Zooarchaeology (sometimes called archaeozoology), also known as faunal analysis, is a branch of archaeology that studies remains of animals from archaeological sites. Faunal remains are the items left behind when an animal dies. These include bon ...

cetology Cetology (from Greek , ''kētos'', " whale"; and , ''-logia'') or whalelore (also known as whaleology) is the branch of marine mammal science that studies the approximately eighty species of whales, dolphins, and porpoises in the scientific order ...

entomology Entomology () is the scientific study of insects, a branch of zoology. In the past the term "insect" was less specific, and historically the definition of entomology would also include the study of animals in other arthropod groups, such as arac ...

helminthology Helminthology is the study of parasitic worms (helminths). The field studies the taxonomy of helminths and their effects on their hosts. The origin of the first compound of the word is the Greek '' ἕλμινς'' - helmins, meaning "worm". In ...

, herpetology,

histology Histology, also known as microscopic anatomy or microanatomy, is the branch of biology which studies the microscopic anatomy of biological tissues. Histology is the microscopic counterpart to gross anatomy, which looks at larger structures vis ...

, ichthyology, malacology, mammalogy,

morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines *Morphology (archaeology), study of the shapes or forms of artifacts *Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies, ...

nematology Nematology is the scientific discipline concerned with the study of nematodes, or roundworms. Although nematological investigation dates back to the days of Aristotle or even earlier, nematology as an independent discipline has its recognizable ...

ornithology Ornithology is a branch of zoology that concerns the "methodological study and consequent knowledge of birds with all that relates to them." Several aspects of ornithology differ from related disciplines, due partly to the high visibility and th ...

palaeozoology Palaeozoology, also spelled as Paleozoology (Greek: παλαιόν, ''palaeon'' "old" and ζῷον, ''zoon'' "animal"), is the branch of paleontology, paleobiology, or zoology dealing with the recovery and identification of multicellular anima ...

, pathology,

primatology Primatology is the scientific study of primates. It is a diverse discipline at the boundary between mammalogy and anthropology, and researchers can be found in academic departments of anatomy, anthropology, biology, medicine, psychology, vete ...

protozoology Protozoology is the study of protozoa, the "animal-like" (i.e., motile and heterotrophic) protists. The Protozoa are considered to be a subkingdom of Protista. They are free-living organisms that are found in almost every habitat. All humans have pr ...

, taxonomy, and zoogeography.

Ecology

''Ecology'' (from el, οἶκος, "house", or "environment"; el, -λογία, label=none, "study of"), meaning "dwelling place, distributional area" —quoted from Stauffer (1957). is a branch of

concerning interactions among organisms and their

biophysical environment A biophysical environment is a biotic and abiotic surrounding of an organism or population, and consequently includes the factors that have an influence in their survival, development, and evolution. A biophysical environment can vary in scale f ...

, which includes both biotic and

abiotic In biology and ecology, abiotic components or abiotic factors are non-living chemical and physical parts of the environment that affect living organisms and the functioning of ecosystems. Abiotic factors and the phenomena associated with them unde ...

components. Topics of interest include the

biodiversity Biodiversity or biological diversity is the variety and variability of life on Earth. Biodiversity is a measure of variation at the genetic (''genetic variability''), species (''species diversity''), and ecosystem (''ecosystem diversity'') le ...

, distribution, biomass, and populations of organisms, as well as cooperation and competition within and between

. Ecosystems are dynamically interacting systems of organisms, the

communities A community is a social unit (a group of living things) with commonality such as place, norms, religion, values, customs, or identity. Communities may share a sense of place situated in a given geographical area (e.g. a country, village, tow ...

they make up, and the non-living components of their environment. Ecosystem processes, such as primary production, pedogenesis,

nutrient cycling A nutrient cycle (or ecological recycling) is the movement and exchange of inorganic and organic matter back into the production of matter. Energy flow is a unidirectional and noncyclic pathway, whereas the movement of mineral nutrients is cycli ...

, and niche construction, regulate the flux of energy and matter through an environment. These processes are sustained by organisms with specific life history traits.

Social sciences

''Social science'' is the branch of science devoted to the study of

societies A society is a group of individuals involved in persistent social interaction, or a large social group sharing the same spatial or social territory, typically subject to the same political authority and dominant cultural expectations. Societ ...

and the relationships among individuals within those societies. The term was formerly used to refer to the field of sociology, the original "science of society", established in the 19th century. In addition to sociology, it now encompasses a wide array of

s, including

anthropology Anthropology is the scientific study of humanity, concerned with human behavior, human biology, cultures, societies, and linguistics, in both the present and past, including past human species. Social anthropology studies patterns of behavi ...

archaeology Archaeology or archeology is the scientific study of human activity through the recovery and analysis of material culture. The archaeological record consists of artifacts, architecture, biofacts or ecofacts, sites, and cultural landscape ...

, economics,

human geography Human geography or anthropogeography is the branch of geography that studies spatial relationships between human communities, cultures, economies, and their interactions with the environment. It analyzes spatial interdependencies between social i ...

, linguistics, political science, and psychology. Positivist social scientists use methods resembling those of the natural sciences as tools for understanding society, and so define science in its stricter modern sense. Interpretivist social scientists, by contrast, may use social critique or symbolic interpretation rather than constructing empirically falsifiable theories. In modern academic practice, researchers are often

eclectic Eclectic may refer to: Music * ''Eclectic'' (Eric Johnson and Mike Stern album), 2014 * ''Eclectic'' (Big Country album), 1996 * Eclectic Method, name of an audio-visual remix act * Eclecticism in music, the conscious use of styles alien to th ...

, using multiple methodologies (for instance, by combining both

quantitative Quantitative may refer to: * Quantitative research, scientific investigation of quantitative properties * Quantitative analysis (disambiguation) * Quantitative verse, a metrical system in poetry * Statistics, also known as quantitative analysis ...

and qualitative research). The term " social research" has also acquired a degree of autonomy as practitioners from various disciplines share in its aims and methods.

Applied sciences

''Applied science'' is the use of existing scientific knowledge to achieve practical goals, like technology or inventions. Within natural science, disciplines that are basic science develop basic '' information'' to explain and perhaps predict phenomena in the natural world. Applied science is the use of scientific processes and knowledge as the means to achieve a particularly practical or useful result. This includes a broad range of applied science-related fields, including engineering and medicine. Applied science can also apply formal science, such as statistics and

probability theory Probability theory is the branch of mathematics concerned with probability. Although there are several different probability interpretations, probability theory treats the concept in a rigorous mathematical manner by expressing it through a set ...

, as in epidemiology. Genetic epidemiology is an applied science applying both biological and statistical methods.

Relationships between the branches

The relationships between the branches of science are summarized by the table

Visualizations and metascience

OpenAlex and Scholia can be used to visualize and explore scientific fields and research topics. Metascience refers to or includes a field of science that is about science itself.