Biology or historically also life science (from ancient Greek βίος bíos " life " and λόγος lógos here: " teaching ", see also -logy ) is the science of living beings . It is a branch of the natural sciences and deals with the general laws of living things as well as with the peculiarities of individual living beings: for example, with their development , their blueprint and the physical and biochemical processes within them. In the field of biology , research is carried out in numerous sub-areas. The sub-areas that are generally geared towards the understanding of living things include in particular biophysics , genetics , molecular biology , ecology , physiology , theoretical biology and cell biology . Botany ( plants ), zoology ( animals ) and microbiology ( microorganisms and viruses ) deal with large groups of living beings .
The objects of consideration in biology include a. Molecules , organelles , cells and cell clusters, tissues and organs , but also the behavior of individual organisms and their interaction with other organisms in their environment . This variety of objects under consideration means that a variety of methods , theories and models are applied and taught in the subject of biology .
In recent times, as a result of the flowing transitions into other fields of science (e.g. medicine , psychology and nutritional sciences ) and because of the interdisciplinary nature of research, in addition to the term biology, further terms have been established for the biological research directions and training courses, such as life sciences , life sciences and life sciences .
There were already thoughts about life around 600 BC. BC by the Greek natural philosopher Thales of Miletus , who is said to have designated water as the beginning - the source - of all things. From antiquity to the Middle Ages, however, biology was mainly based on the observation of nature , not on experiments . In the interpretation of the observations, theories such as the four-element doctrine or various spiritual attitudes were often incorporated , including the creation myth of the biblical Genesis , according to which "God the LORD formed man out of dust from the earth" ( Adam ) and he " the breath of life "blew into his nose" - "and so man became a living being."
It wasn't until the beginning of the scientific revolution in the early modern period that naturalists began to break away from the supernatural . In the 16th and 17th centuries, for example, knowledge of anatomy was expanded through the resumption of sections and inventions such as the microscope enabled completely new insights into a world that had previously been almost invisible. 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 established the theory of evolution .
The term 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 ( Hydrogeneology , 1802) used and defined it for the first time. The word itself was used as early as 1797 by Theodor Gustav August Roose (1771–1803) in the foreword of his essay Basics of the Doctrine of Life Force and appears in the title of the third volume of Michael Christoph Hanow's 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 , mathematical biology began to be established in the 1920s .
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. Huschke, C. Vogt, P. J. Möbius and T. aL aW von Bischoff, among others, tried to prove the intellectual inferiority of women in order to prevent their admission to studies. 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.
- 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 - publishes the 37-volume Historia Naturalis on 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
- 1839 Theodor Schwann and Matthias Jacob Schleiden - founders of the cell theory
- 1858 Charles Darwin (1842, unpublished) and Alfred Russel Wallace - independently founded the theory of evolution
- 1866 Gregor Mendel - first publication on experiments with plant hybrids establishes genetics
- In 1925, with the establishment of the Lotka-Volterra equations (equations to describe the predator-prey relationship ), the age of mathematical biology began
- 1935 first clear detection of a virus by Wendell Meredith Stanley
- 1944 Oswald Avery shows that DNA, and not proteins as previously assumed, 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 provide the basic equations of electrophysiology on
- 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 )
- 1973 John Maynard Smith and George R. Price introduce the concept of Evolutionary Stable Strategy .
- 1982 Hypothesis about prions (infectious agent without genetic material) by Stanley Prusiner . In the early 1990s, prions became popular due to what is known as 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 by the Human Genome Project
Classification of subject areas
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 sorted using 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, considers many groups of organisms and zoology researches both the molecular level of animals and their behavior among one another. The figure shows in a compact form an order that connects both systems.
The following is an overview of the various 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.
It is the science and teaching of microorganisms , that is, of living beings that cannot be seen as individuals with the naked eye: bacteria and other single-cell organisms , certain fungi , single- and few-cell algae ("microalgae") and viruses .
Botany / plant science
Botany (also plant science) emerged from medicinal plant science and is primarily concerned with the structure, the tribal history, the distribution and the metabolism of plants.
Zoology / animal biology
The zoology (also animal biology) deals mainly with the construction, the tribal history, the distribution and the expressions of life of the animals.
Human biology is a discipline that deals in the narrower sense with human biology and the biological foundations of human medicine and, in a broader sense, with the sub-areas of biology that are relevant to humans. Human biology emerged as an independent scientific discipline only in the second half of the 20th century.
It is related to biological anthropology , which is, however, counted as anthropology . The aim of the biological anthropology with their sub-regions Primatology , evolution , sports anthropology , paleoanthropology , Population biology, industrial anthropology , Genetics , growth ( Auxology ) constitution and forensics is the description, cause analysis and evolution biological interpretation of the diversity of biological features of the hominids . Her methods are both descriptive and analytical.
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 are an important object of research as stores of genetic information. 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 things. 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 oxygen , nitrogen and sulfur . Metals also play a role in very small amounts in some biomolecules (e.g. chlorophyll or hemoglobin ).
Biological disciplines that deal with this level are:
- Biochemistry ,
- Genetics and epigenetics (DNA-independent inheritance of traits),
- Molecular biology ,
- Pharmaceutical Biology and Toxicology .
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 to take place simultaneously, including opposing ones. 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 cell (like some fungi).
Biological disciplines, primarily at this level (examples) :
- Histology , anatomy
- Immunology , infection biology , neurobiology
- Mycology , microbiology , protozoology , phycology
- Cell biology, cell physiology
Every living being is the result of a development. According to Ernst Haeckel , this development can be viewed on two different levels over time:
- Through evolution , the shape of organisms can develop further over the generations ( phylogenesis ).
- The ontogeny is the individual development of an individual organism from conception through its various stages of life or 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.
Gregor Mendel is considered to be the founder of genetics . This is how he discovered Mendel's rules , which were later named after him, but which were not accepted and confirmed in science until 1900. By far the most important part of genetics today is molecular genetics , which was founded in the 1940s.
Behavioral biology studies the behavior of animals and humans. It describes 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.
Ecology / environmental biology
The department of ecology (also environmental biology) 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 .
In connection with the description and investigation of social associations such as herds or packs, the social sciences applied to humans can also be seen.
- 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 .
- The Landscape Ecology is directed to the spatial characteristics of ecological relationships and control circuits. She researches the interaction between biodiversity and geodiversity at the level of the resulting landscape diversity .
- In human ecology , the mutual relationships between humans and the environment are particularly important.
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
The phylogeny describes the development of a type in the course of generations. Here evolutionary biology considers the long-term adaptation to environmental conditions and the division into new species .
On the basis of 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:
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 phylogenetic tree is drawn as a common representation . The connecting lines between the individual groups represent the evolutionary relationship. The shorter the path between two species in such a tree, the closer they are to each other. The sequence of a widespread gene is often used as a measure of the relationship.
As a synthesis of ecology, evolutionary biology and systematics in a certain sense, 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.
In this field, bioengineers try to create artificial viable systems that are controlled by a genome like natural organisms.
Theoretical biology (also systemic biology) deals with mathematically formulated basic principles of biological systems at all organizational levels.
Systems biology tries to understand organisms in their functional entirety. It follows system theory and uses not only mathematical models but also computer simulations. It overlaps with theoretical biology.
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. The formulation of general principles in biology and the making of connections are based on both empirical data and 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. The physics , for example, provides a variety research methods. Simple optical devices such as the light microscope allow the observation of 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.
The 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 today dealt with using bioinformatic methods.
The math is used as the main instrument of theoretical biology describing and analyzing more general context of 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 makeup 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 a central 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 the agriculture crops by means of molecular genetics with resistance provided to pests and made less sensitive to drought and nutrient deficiency. In the luxury food and food 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.
"Gallery of Life" (representatives of various groups of living beings)
- List of all Wikipedia articles whose title starts with biology
- List of all Wikipedia articles whose title includes biology
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Änne Bäumer : History of Biology.
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- Virtual Library of Biology ( vifabio )
- www.BioLib.de - old books from biology with many original images
- www.biologie.uni-hamburg.de "The autonomy of biology" - extensive article by Ernst Mayr
- Association of Biology, Biosciences and Biomedicine in Germany
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- Austrian Biologist Association Association of Austrian Biologists
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- Londa Schiebinger: Beautiful spirits. Women in the dawn of modern science. Klett-Cotta, Stuttgart 1993, ISBN 3-608-91259-2 .
- 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).
- Arthur Kirchhoff: The Academic Woman. Reports from outstanding university professors, women's teachers and writers on the ability of women for academic studies and professions. Steinitz, Berlin 1897.
- Heinz-Jürgen Voss : Feminist criticism of science. Using the example of natural science biology. In: Ulrike Freikamp u. a. (Ed.): Criticism with method? Research methods and social criticism. (PDF; 1.2 MB) Dietz, Berlin 2008, ISBN 978-3-320-02136-8 ( Texts. 42), pp. 233-252.
- 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 organism in Cuvier, Leibniz and Kant . Campus, Frankfurt / M. 2000.
- The discovery of viruses
- Scobey: Polio Caused By Exogenous Virus? ( Memento from June 29, 2004 in the Internet Archive )
- 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 .
- John Maynard Smith, George R. Price: The Logic of Animal Conflict. In: Nature . 246, 1973, pp. 15-18, doi : 10.1038 / 246015a0 .
- What is ethnobiology?
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