What are the different areas of biology

biology (Old Greek βίος bíos 'Life' and λόγος lógos 'Doctrine') is the science of living things. It deals with the general laws of living things, but also with the special characteristics of living beings, their structure, organization and development as well as their diverse structures and processes.

Biology is very extensive and can be divided into many specialist areas. The general areas of biology include in particular general zoology, general botany, but also physiology, biochemistry, biophysics, ecology, anthropology and theoretical biology. In recent times, as a result of the flowing transitions into other areas of science (e.g. medicine and psychology) and the interdisciplinary character of research, the terms life sciences, Life sciences or life sciences established.

The objects of observation for biologists range from molecular structures through organelles, cells, cell clusters, tissues and organs to complex organisms. In larger contexts, the behavior of individual organisms as well as their interaction with others and their environment is examined. The methods, theories and models used are just as diverse.

Biologists are trained at universities as part of a biology degree.


There were already reflections on life around 600 BC. At Thales of Miletus. He believed that life came from water. From ancient times to the Middle Ages, biology was mainly based on observations of nature. The interpretation often included things like the power of the elements or various spiritual approaches, including the religious creation myth of biblical Genesis. A carefully formed lump of clay (Adam) breathed with the "divine breath" - and so he became a living soul. (For more information on the associated problem, see Life.)

It was only with the beginning of the scientific revolution that people began to detach themselves from the supernatural and describe observations. In the 16th and 17th centuries, knowledge of anatomy expanded with the resumption of sections and new inventions, such as the microscope. The development of chemistry brought advances in biology as well. Experiments that led to the discovery of molecular life processes such as fermentation and photosynthesis became possible. In the 19th century, the foundations were laid for two great new branches of science in natural research: Gregor Mendel's work on plant crossings established the theory of inheritance and later genetics and works by Jean-Baptiste de Lamarck, Charles Darwin and Alfred Russel Wallace described the theory of evolution.

The designation biology, used in the modern sense, seems to have been introduced several times independently of one another. Gottfried Reinhold Treviranus (Biology or Philosophy of Living Nature, 1802) and Jean-Baptiste Lamarck (Hydrogeology, 1802) used and defined it for the first time. The word itself was used as early as 1797 by Theodor Gustav August Roose in the preface to his writing Basic principles of the doctrine of the life force used and dived in the title of the third volume by Michael Christoph Hanows Philosophiae naturalis sive physicae dogmaticae: Geologia, biologia, phytologia generalis et dendrologia from 1766 on. The German anatomist and physiologist Karl Friedrich Burdach was one of the first to shape “biology” in a comprehensive sense.

With the further development of research methods, biology penetrated into ever smaller dimensions. In the 20th century, the sub-areas of physiology and molecular biology developed. Fundamental structures such as DNA, enzymes, membrane systems and the entire machinery of the cell have since been made visible at the atomic level and their function can be examined more closely. At the same time, the evaluation of data collection with the help of statistical methods became more and more important and replaced the description of individual phenomena, which was increasingly perceived as merely anecdotal. As a branch of theoretical biology, a mathematical biology to establish.

Since the end of the 20th century, new applied disciplines have developed from biology: For example, genetic engineering complements the classic methods of animal and plant breeding and opens up additional possibilities for adapting the environment to human needs.

Practical biology and medicine were among the disciplines in which in the German Empire at the end of the 19th century the most vehement resistance to the admission of women was exercised compared with other disciplines. E.g. E. Huschke, C. Vogt, P. J. Möbius and T. a.L. a.W. von Bischoff to prove the intellectual inferiority of women in order to prevent their admission to studies.[1][2] In contrast, the descriptive biological sciences (but also other descriptive natural sciences such as physics and mathematics) were further. In a study by A. Kirchhoff (1897), the still exclusively male teachers showed themselves to be mostly open to the admission of women to the course.[3][4] Meanwhile, the proportion of women and men who start studying biology is the same; Even in more prestigious and well-paid positions, the proportion of women in biology is slowly increasing (it is currently almost 15% for professorships).[5]

Particular advances in biology

Title page of Robert Hooke's major work, published in 1665 Micrographiacontaining numerous drawings made with the aid of a microscope.
  • 600 BC Chr. Thales of Miletus - sets up the first theory of the origin of life
  • 350 BC Chr. Aristotle - various writings on zoology
  • 1st century AD Pliny - published the 37-volume Historia Naturalis to botany and zoology
  • 1665 Robert Hooke - Description of cells in cork tissue
  • 1683 Antoni van Leeuwenhoek - discovers bacteria, protozoa, blood cells and sperm through microscopy
  • 1758 Carl von Linné - establishes the taxonomy in the animal and plant kingdom that is still valid today in his work Systema Naturae
  • Around 1800 the conception of living beings as organisms emerged (Georges Cuvier, Kant), which is constitutive for (modern) biology[6]
  • 1839 Theodor Schwann and Matthias Jacob Schleiden - founders of the cell theory
  • 1858 Charles Darwin (1842, unpublished) and Wallace - independently founded the theory of evolution
  • 1866 Gregor Mendel - first publication on experiments with plant hybrids establishes genetics
  • The age of mathematical biology begins in 1925 with the establishment of the Lotka-Volterra equations (equations for describing the predator-prey relationship)
  • 1935 first clear detection of a virus by Wendell Meredith Stanley[7][8]
  • 1944 Oswald Avery shows that DNA, and not, as previously suspected, proteins, is the carrier of genetic information
  • 1950 Barbara McClintock publishes her (for a long time not recognized) discovery of movable elements in the genetic material (transposons). Today their discovery forms the basis of genetic engineering
  • 1952 Alan Lloyd Hodgkin and Andrew Fielding Huxley set up the basic equations of electrophysiology
  • 1953 James D. Watson and Francis Crick publish the double helix structure of DNA (Rosalind Franklin and Maurice Wilkins also played an important role in determining the structure)[9]
  • 1973 John Maynard Smith and George R. Price introduce the concept of Evolutionary Stable Strategy.[10]
  • 1982 Hypothesis about prions (infectious agent without ergut) by Stanley Prusiner. In the early 1990s, prions became popular because of the so-called mad cow disease.
  • 1983 Kary Mullis invents the polymerase chain reaction (PCR). From now on, DNA molecules can be reproduced millions of times in the laboratory
  • 1990 - 2003 Sequencing of the human genome through the Human Genome Project

Classification of subject areas

Subject classification of biology

Biology as a science can be subdivided into sub-areas through the multitude of living beings, investigation techniques and questions according to various criteria: On the one hand, the subject can be divided according to the respective groups of organisms considered (plants in botany, bacteria in microbiology). On the other hand, it can also be arranged on the basis of the processed micro- and macroscopic hierarchy levels (molecular structures in molecular biology, cells in cell biology).

The various systems overlap, however, since genetics, for example, looks at many groups of organisms and zoology researches both the molecular level of animals and their mutual behavior. The figure shows in compact form an order that connects both systems.

The following is an overview of the different hierarchy levels and the related subjects of biology. Its classification is based on the illustration. Subjects that primarily consider the respective level are listed as examples.


Botany emerged from the science of medicinal plants and is mainly concerned with the structure, the tribal history, the distribution and the metabolism of plants.


The zoology is mainly concerned with the structure, the tribal history, the distribution and the expressions of life of animals.

Molecular biology

Molecular structure of a DNA double helix

The basic level of the hierarchy is molecular biology. It is the biological sub-discipline that deals with molecules in living systems. The biologically important classes of molecules include nucleic acids, proteins, carbohydrates and lipids.

The nucleic acids DNA and RNA as stores of genetic information are an important object of research. The various genes and their regulation are deciphered and the proteins encoded in them are examined. Proteins are also of great importance. For example, in the form of enzymes as biological catalysts, they are responsible for almost all substance-converting reactions in living beings. In addition to the groups listed, there are many more, such as alkaloids, terpenes and steroids. What they all have in common is a basic structure made of carbon, hydrogen and often also oxygen, nitrogen and sulfur. Metals also play a role in very small quantities in some biomolecules (e.g. chlorophyll or hemoglobin).

Biological disciplines that deal with this level are:


It is the science and doctrine of microorganisms, that is, of living beings that cannot be seen as individuals with the naked eye: bacteria and other unicellular organisms, certain fungi, single- and few-cell algae ("microalgae") and viruses.

Cell biology (cytology)

Cells are basic structural and functional units of living things. A distinction is made between prokaryotic cells, which have no nucleus and are poorly subdivided, and eukaryotic cells, whose genetic information is located in a cell nucleus and which contain various cell organelles. Cell organelles are reaction spaces within a cell that are delimited by single or double membranes. They enable different chemical reactions, including opposing ones, to take place simultaneously. A large part of the living world is made up of single-cell organisms. They can consist of a prokaryotic cell (the bacteria) or a eukaryotic one (like some fungi).

In multicellular organisms, many cells of the same type and function combine to form tissues. Several tissues with interlocking functions form an organ.

Biological disciplines, primarily at this level (examples):

Developmental biology

Every living being is the result of a development. According to Ernst Haeckel, this development can be viewed on two different levels in terms of time:
- Through evolution, the shape of organisms can develop further over the generations (phylogenesis)
- The ontogenesis is the individual development of a single organism from its conception through its various life stages to death. Developmental biology studies this process.


Physiology deals with the physical, biochemical and information processing functions of living things. Physiological research and training takes place in the academic fields of biology and medicine as well as in psychology.



Behavioral biology

Behavioral biology studies the behavior of animals and humans. It describes the behavior, makes comparisons between individuals and species and tries to explain the emergence of certain behaviors in the course of tribal history, ie the "benefits" for the individual.


The Department of Ecology deals with the interactions between organisms and the abiotic and biotic factors of their habitat on different organizational levels.

  • Individuals: Autecology primarily considers the effects of abiotic factors such as light, temperature, water supply or seasonal changes on the individual. Biological disciplines that also consider this level are, for example, anthropology, zoology, botany and behavioral biology.
  • Populations (demecology):

A population is a reproductive community within a species in a temporally and spatially limited area. Population ecology primarily considers the dynamics of the populations of a habitat due to changes in the birth and death rate, changes in the food supply or abiotic environmental factors. This level is also studied by behavioral biology and sociobiology.

The social sciences applied to humans can also be seen in connection with the description and investigation of social associations such as herds or packs.

  • Biocenoses (synecology): They represent communities of organisms. Plants, animals, fungi, protozoa and bacteria are mostly dependent on one another in an ecosystem and influence one another. They are part of material cycles in their habitat up to global material cycles such as the carbon cycle.

Living beings can influence each other positively (e.g. symbiosis), negatively (e.g. predators, parasitism) or simply not at all.

Community (biocenosis) and habitat (biotope) together form an ecosystem.

Biological disciplines dealing with ecosystems (examples):

Since the evolution of organisms can lead to an adaptation to a certain environment, there is an intensive exchange between the two disciplines, which is particularly evident in the discipline of evolutionary ecology.

Evolutionary Biology and Systematics

Main articles: Evolution, Biological Systematics and Taxonomy

The phylogenesis describes the development of a species over generations. Here evolutionary biology considers the long-term adaptation to environmental conditions and the division into new species.

On the basis of the phylogenetic development, the biological taxonomy arranges all living things in a scheme. The totality of all organisms is divided into three groups, the domains, which in turn are further subdivided:

Phylogenetic tree showing the division of living beings into the three domains

Special zoology deals with the classification of animals in this system, with the classification of plants with special botany, with the classification of archaea, bacteria and fungi with microbiology.

A common representation is a phylogenetic tree drawn. The connecting lines between the individual groups represent the evolutionary relationship. The shorter the path between two species in such a tree, the more closely they are related to each other. The sequence of a widespread gene is often used as a measure of the relationship.

As in a certain sense a synthesis of ecology, evolutionary biology and systematics, biodiversity research has been established since the late 1980s, which also builds bridges to efforts to protect biodiversity and to political agreements on protection and sustainability.


Anthropology is the doctrine of human beings. The aim of biological anthropology with its sub-areas of primatology, evolution theory, sport anthropology, paleoanthropology, population biology, industrial anthropology, genetics, growth (auxology), constitution and forensics is the description, cause analysis and evolutionary interpretation of the diversity of biological characteristics of hominids (family of the order primates, the includes fossil and recent humans). Her methods are both descriptive and analytical.

Theoretical biology

Theoretical biology deals with mathematically formulated basic principles of biological systems at all organizational levels.

Working methods of biology

Biology uses many commonly used scientific methods, such as structured observation, documentation (notes, photos, films), hypothesis formation, mathematical modeling, abstraction and experiments. When formulating general principles in biology and making connections, one relies on empirical data as well as on mathematical theorems. The more attempts with different starting points indicate the same result, the more likely it will be recognized as valid. However, this pragmatic view is controversial; Karl Popper in particular took a stand against them. In his view, theories cannot be substantiated but only undermined through experimentation or observation, and even through unsuccessful attempts to refute a theory (see Underdetermination of theories through evidence).

Insights into the most important structures and functions of living beings are possible with the help of related sciences. Physics, for example, provides a multitude of investigation methods. Simple optical devices such as the light microscope make it possible to observe smaller structures such as cells and cell organelles. This brought a new understanding of the structure of organisms and cell biology opened up a new field of research. A range of high-resolution imaging methods, such as fluorescence microscopy or electron microscopy, are now standard.

Biochemistry has emerged as an independent subject between the sciences of biology and chemistry. It combines the knowledge of the chemical and physical properties of the building blocks of life with the effect on the overall biological structure. With chemical methods it is possible, for example, to provide biomolecules with a dye or a radioactive isotope in biological experiments. This enables them to be tracked through various cell organelles, the organism or through an entire food chain.

Bioinformatics is a very young discipline between biology and computer science. Bioinformatics tries to solve biological problems using computer science methods. In contrast to theoretical biology, which often does not work with empirical data to solve specific questions, bioinformatics uses biological data. One of the major research projects in biology, genome sequencing, was only possible with the help of bioinformatics. Bioinformatics is also used in structural biology, where there are close interactions with biophysics and biochemistry. One of the fundamental questions in biology, the question of the origin of living beings (also referred to as the phylogenetic tree of life, see figure above), is now dealt with using bioinformatic methods.

Mathematics serves as the main instrument of theoretical biology for the description and analysis of general relationships in biology. For example, modeling by systems of ordinary differential equations is found to be fundamental in many areas of biology (such as evolutionary theory, ecology, neurobiology, and developmental biology). Phylogenetic questions are dealt with using methods of discrete mathematics and algebraic geometry.

Statistical methods are used for the purposes of test planning and analysis.

The different biological sub-disciplines use different systematic approaches:

  • Mathematical biology: establishing and proving general theorems of biology.
  • Biological systematics: characterize living beings and classify them into a system based on their properties and features
  • Physiology: Decomposition and description of organisms and their components with subsequent comparison with other organisms with the aim of explaining their function
  • Genetics: cataloging and analyzing the genetic make-up and inheritance
  • Behavioral biology, sociobiology: Observing and explaining the behavior of individuals, of similar animals in the group and to other animal species
  • Ecology: Observing one or more species in their habitat, their interrelationship and the effects of biotic and abiotic factors on their way of life
  • Use approach: examine the breeding and keeping of crops, livestock and beneficial microorganisms and optimize them by varying the keeping conditions

Areas of application of biology

Biology is a scientific discipline that has many areas of application. Biological research provides insights into the structure of the body and the functional relationships. They form the basis on which medicine and veterinary medicine investigate the causes and effects of diseases in humans and animals. In the field of pharmacy, drugs such as insulin or numerous antibiotics are obtained from genetically modified microorganisms rather than from their natural biological source, because these processes are cheaper and many times more productive. For agriculture, crops are made resistant to pests by means of molecular genetics and made less sensitive to drought and nutrient deficiencies. In the food and beverage industry, biology ensures a wide range of longer-lasting and biologically higher quality foods. Here, too, individual food components come from genetically modified microorganisms. Today, the rennet for making cheese is no longer extracted from calf stomachs, but is produced microbially.

Other related subject areas that have their own fields of application are ethnobiology[11], Bionics, bioinformatics and biotechnology.

See also

 Portal: biology - Overview of Wikipedia content on the subject of biology

Individual evidence

  1. ↑ Londa Schiebinger: Beautiful ghosts. Women in the dawn of modern science. Klett-Cotta, Stuttgart 1993, ISBN 3-608-91259-2.
  2. ↑ Katrin Schmersahl: Medicine and gender. On the construction of the gender category in 19th century medical discourse. Leske and Budrich, Opladen 1998, ISBN 3-8100-2009-5 (Social science studies. Issue 36).
  3. ↑ Arthur Kirchhoff: The academic woman. Reports from outstanding university professors, women's teachers and writers on the qualifications of women for academic studies and professions. Steinitz, Berlin 1897.
  4. ↑ Heinz-Jürgen Voss: Feminist science criticism. Using the example of natural science biology. In: Ulrike Freikamp et al. (Ed.): Criticism with method? Research methods and social criticism. Dietz, Berlin 2008, ISBN 978-3-320-02136-8 (Texts. 42), pp. 233-252.
  5. ↑ Hochschul-Informations-System GmbH (ed.): First-year students in the winter semesters 2003/04 and 2004/05. Paths to study, choice of study and university, situation at the start of studies. Issue 180, 2005.
  6. ↑ Foucault, Michel 1974: The Order of Things: An Archeology of the Human Sciences. Suhrkamp, ​​Frankfurt / M .; Cheung, Tobias: The organization of the living. The origin of the biological concept of the organism in Cuvier, Leibniz and Kant. Campus, Frankfurt / M. 2000.
  7. ↑ The discovery of viruses
  8. ↑ Scobey: Polio Caused By Exogenous Virus?
  9. ↑ Brenda Maddox: Rosalind Franklin. The discovery of DNA or a woman's struggle for scientific recognition. Campus, Frankfurt am Main 2003, ISBN 3-593-37192-8.
  10. ↑ John Maynard Smith, George R. Price: The Logic of Animal Conflict. In: Nature. 246, 1973, pp. 15-18, doi: 10.1038 / 246015a0.
  11. ↑ What is ethnobiology?


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