Biology is the science of life . It is concerned with the characteristics and behaviors of organisms , how species and individuals comeinto existence, and the interactions they have with each other and with their environment .
Overview of biology
Biology encompasses a broad spectrum of academic fields that are often viewed as independent disciplines. Together, they studylife over a wide range of scales :
Fields of study in biology
People and history
List of topics
Evolution and biology
One of the central, organizing concepts in biology is that all life has descended from a common origin through a process of evolution . Charles Darwin established evolution as a viable theory by articulating itsdriving force: natural selection . ( Alfred RussellWallace is commonly recognized as the co-discoverer of this concept). Genetic drift was embraced as an additional mechanism in the so-called modern synthesis . The evolutionary history of a species —which tells the characteristics of the various species from which it descended—together withits genealogical relationship to every other species is called its phylogeny .Widely varied approaches to biology generate information about phylogeny. These include the comparisons of DNA sequences conducted within molecular biology or genomics , and comparisons of fossils or other records of ancient organisms in paleontology . Biologists organize and analyze evolutionary relationships through various methods, including phylogenetics , phenetics ,and cladistics . Major events in the evolution of life, as biologists currentlyunderstand them, are summarized on this evolutionarytimeline .
Classification of life
The classification of living things is called systematics , or taxonomy , and should reflect the evolutionary trees ( phylogenetic trees ) of the different organisms. Taxonomy piles up organisms in groups called taxa , while systematics seeks their relationships. The dominant system is called Linnaean taxonomy , which includes ranks and binomial nomenclature . How organisms are named is governed byinternational agreements such as the International Code of Botanical Nomenclature (ICBN), the International Code ofZoological Nomenclature (ICZN), and the International Code of Nomenclature of Bacteria (ICNB). A fourth DraftBioCode was published in 1997 in an attempt to standardize naming in the three areas, but it does not appear to have yet beenformally adopted. The International Code of Virus Classification andNomenclature (ICVCN) remains outside the BioCode.
Traditionally, living things were divided into five kingdoms:
However, this five-kingdom system is now considered by many to be outdated. More modern alternatives generally begin with the three-domain system :
These domains reflect whether cells have nuclei or not as well as differences in cell exteriors.
History of the word "biology"
Formed by combining the Greek βίος (bios), meaning 'life', and λόγος(logos), meaning 'word', the word "biology" in its modern sense seems to have been introduced independently by Gottfried Reinhold Treviranus (Biologie oderPhilosophie der lebenden Natur, 1802 ) and by Jean-Baptiste Lamarck (Hydrogéologie, 1802). The word itself is sometimes said to havebeen coined in 1800 by Karl Friedrich Burdach , but it appears in the title of Volume 3 of Michael ChristophHanov 's Philosophiae naturalis sive physicae dogmaticae: Geologia, biologia, phytologia generalis etdendrologia, published in 1766 .
External links and resources
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