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Evolutionary biology is a sub-field of biology concerned with the study of evolutionary processes that have given rise to the diversity of life on earth. It includes studies concerning the origin of species, descent of species as well as their change, multiplication and diversity over time. Someone who studies evolutionary biology is known as an evolutionary biologist. To philosopher Kim Sterelny, "the development of evolutionary biology since 1858 is one of the great intellectual achievements of science".[1]
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The study of evolution is the unifying concept in evolutionary biology. Evolutionary biology is a conceptual subfield of biology intersects with other subfields that are delimited by organizational level (e.g. cell biology, population biology), taxonomic level (e.g. zoology, ornithology, herpetology) or angle of approach (e.g. field biology, theoretical biology, experimental evolution, paleontology). Often, these intersections are combined into specific fields such as evolutionary ecology and evolutionary developmental biology.
Evolutionary biology as an academic discipline in its own right emerged as a result of the modern evolutionary synthesis in the 1930s and 1940s.[2] It was not until the 1970s and 1980s, however, that a significant number of universities had departments that specifically included the term evolutionary biology in their titles. In the United States, as a result of the rapid growth of molecular and cell biology, many universities have split (or aggregated) their biology departments into molecular and cell biology-style departments and ecology and evolutionary biology-style departments (which often have subsumed older departments in botany, zoology and the like). The subdiscipline of paleontology is often found in earth science/geology/geoscience departments.
Microbiology has recently developed into an evolutionary discipline. It was originally ignored due to the paucity of morphological traits and the lack of a species concept in microbiology. Now, evolutionary researchers are taking advantage of our extensive understanding of microbial physiology, the ease of microbial genomics, and the quick generation time of some microbes to answer evolutionary questions. Similar features have led to progress in viral evolution, particularly for bacteriophages.
Many biologists have contributed to our current understanding of evolution. The establishment of evolutionary biology as a professional scientific discipline only started with the development of population genetics and the formulation of the modern evolutionary synthesis. Theodosius Dobzhansky and E. B. Ford were particularly important in the establishment of an empirical research programme for evolutionary biology.[3] Ernst Mayr, George Gaylord Simpson and G. Ledyard Stebbins were also important discipline-builders during the modern synthesis, in the fields of systematics, paleontology and botany, respectively.[3] Through training many future evolutionary biologists, James Crow[4], Richard Lewontin[5], Dan Hartl[6], Marcus Feldman[7][8] and Brian Charlesworth[9] have also made large contributions to building the discipline of evolutionary biology.
Some scientific journals specialize exclusively in evolutionary biology as a whole, including the journals Evolution, Journal of Evolutionary Biology and BMC Evolutionary Biology. Some journals cover sub-specialties within evolutionary biology, such as the journals Systematic Biology, Molecular Biology and Evolution and its sister journal Genome Biology and Evolution, and Cladistics.
Other journals combine aspects of evolutionary biology with other related fields. For example, Molecular Ecology, Proceedings of the Royal Society of London Series B, The American Naturalist and Theoretical Population Biology have overlap with ecology and other aspects of organismal biology. Overlap with ecology is also prominent in the review journals Trends in Ecology and Evolution and Annual Review of Ecology, Evolution, and Systematics. The journals Genetics and PLoS Genetics overlap with molecular genetics questions that are not obviously evolutionary in nature.
Current research in evolutionary biology covers diverse topics, as should be expected given the centrality of evolution to understanding biology. Modern evolutionary biology incorporates ideas from diverse areas of science, such as molecular genetics and even computer science.
First, some fields of evolutionary research try to explain phenomena that were poorly accounted for by the work of the modern evolutionary synthesis. These phenomena include speciation[10], the evolution of sexual reproduction[11], the evolution of cooperation, the evolution of ageing, and evolvability[12].
Second, biologists ask the most straightforward evolutionary question: "what happened and when?". This includes fields such as paleobiology, as well as systematics and phylogenetics.
Third, the modern evolutionary synthesis was devised at a time when nobody understood the molecular basis of genes. Today, evolutionary biologists try to determine the genetic architecture of interesting evolutionary phenomena such as adaptation and speciation. They seek answers to questions such as how many genes are involved, how large are the effects of each gene, to what extent are the effects of different genes interdependent, what sort of function do the genes involved tend to have, and what sort of changes tend to happen to them (e.g. point mutations vs. gene duplication or even genome duplication). Evolutionary biologists try to reconcile the high heritability seen in twin studies with the difficulty in finding which genes are responsible for this heritability using genome-wide association studies.[13]
One challenge in studying genetic architecture is that the classical population genetics that catalyzed the modern evolutionary synthesis needs to be updated to take into account modern molecular knowledge. This requires a great deal of mathematical development, in order to relate DNA sequence data to evolutionary theory as part of a theory of molecular evolution. For example, biologists try to infer which genes have been under strong selection by detecting selective sweeps.[14]
Fourth, the modern evolutionary synthesis involved agreement about which forces contribute to evolution, but not about their relative importance.[15] Current research seeks to determine this. Evolutionary forces include natural selection, sexual selection, genetic drift, genetic draft, developmental constraints, mutation bias and biogeography.
An evolutionary approach is also key to much current research in biology that does not set out to study evolution per se, especially in organismal biology and ecology. For example, evolutionary thinking is key to life history theory. Annotation of genes and their function relies heavily on comparative, i.e. evolutionary, approaches. The field of evo-devo investigates how developmental processes work by using the comparative method to determine how they evolved.
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