Portal:Biology
Introduction
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 information encoded in genes, which can be transmitted to future generations. Another major theme is evolution, which explains the unity and diversity of life. Energy processing is also important to life as it allows organisms to move, grow, and reproduce. Finally, all organisms are able to regulate their own internal environments.
Biologists are able to study life at multiple levels of organization, from the molecular biology of a cell to the anatomy and physiology of plants and animals, and evolution of populations. Hence, there are multiple subdisciplines within biology, each defined by the nature of their research questions and the tools that they use. Like other scientists, biologists use the scientific method to make observations, pose questions, generate hypotheses, perform experiments, and form conclusions about the world around them.
Life on Earth, which emerged more than 3.7 billion years ago, is immensely diverse. Biologists have sought to study and classify the various forms of life, from prokaryotic organisms such as archaea and bacteria to eukaryotic organisms such as protists, fungi, plants, and animals. These various organisms contribute to the biodiversity of an ecosystem, where they play specialized roles in the cycling of nutrients and energy through their biophysical environment. (Full article...)
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A species (pl.: species) is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. Other ways of defining species include their karyotype, DNA sequence, morphology, behaviour, or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. About 14% of these had been described by 2011. All species (except viruses) are given a two-part name, a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specific name or the specific epithet (in botanical nomenclature, also sometimes in zoological nomenclature). For example, Boa constrictor is one of the species of the genus Boa, with constrictor being the species' epithet.
While the definitions given above may seem adequate at first glance, when looked at more closely they represent problematic species concepts. For example, the boundaries between closely related species become unclear with hybridisation, in a species complex of hundreds of similar microspecies, and in a ring species. Also, among organisms that reproduce only asexually, the concept of a reproductive species breaks down, and each clone is potentially a microspecies. Although none of these are entirely satisfactory definitions, and while the concept of species may not be a perfect model of life, it is still a useful tool to scientists and conservationists for studying life on Earth, regardless of the theoretical difficulties. If species were fixed and clearly distinct from one another, there would be no problem, but evolutionary processes cause species to change. This obliges taxonomists to decide, for example, when enough change has occurred to declare that a lineage should be divided into multiple chronospecies, or when populations have diverged to have enough distinct character states to be described as cladistic species. (Full article...)Selected picture -
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Jean Léopold Nicolas Frédéric, Baron Cuvier (23 August 1769 – 13 May 1832), known as Georges Cuvier (French: [ʒɔʁʒ kyvje]), was a French naturalist and zoologist, sometimes referred to as the "founding father of paleontology". Cuvier was a major figure in natural sciences research in the early 19th century and was instrumental in establishing the fields of comparative anatomy and paleontology through his work in comparing living animals with fossils.
Cuvier's work is considered the foundation of vertebrate paleontology, and he expanded Linnaean taxonomy by grouping classes into phyla and incorporating both fossils and living species into the classification. Cuvier is also known for establishing extinction as a fact—at the time, extinction was considered by many of Cuvier's contemporaries to be merely controversial speculation. In his Essay on the Theory of the Earth (1813) Cuvier proposed that now-extinct species had been wiped out by periodic catastrophic flooding events. In this way, Cuvier became the most influential proponent of catastrophism in geology in the early 19th century. His study of the strata of the Paris basin with Alexandre Brongniart established the basic principles of biostratigraphy. (Full article...)General images -
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Blending Inheritance (from History of genetics) -
Efforts are made to preserve the natural characteristics of Hopetoun Falls, Australia, without affecting visitors' access. (from Conservation biology) -
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Inside of a 48-well thermal cycler, a device used to perform polymerase chain reaction on many samples at once (from History of biology) -
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Statue of Robert Koch in Berlin. Koch directly provided proof for the germ theory of diseases, therefore creating the scientific basis of public health, saving millions of lives. For his life's work Koch is seen as one of the founders of modern medicine. (from History of biology) -
An art scape image showing the relative importance of animals in a rain forest through a summary of (a) child's perception compared with (b) a scientific estimate of the importance. The size of the animal represents its importance. The child's mental image places importance on big cats, birds, butterflies, and then reptiles versus the actual dominance of social insects (such as ants). (from Conservation biology) -
Penicillin was viewed as a miracle drug that brought enormous profits and public expectations. (from History of biotechnology) -
Description of rare animals (写生珍禽图), by Huang Quan (903–965) during the Song dynasty. (from History of biology) -
Charles Darwin's first sketch of an evolutionary tree from his First Notebook on Transmutation of Species (1837) (from History of biology) -
Summary of 2006 IUCN Red List categories: EX (Extinct) — EW (Extinct in the Wild) — CR (Critically Endangered) — EN (Endangered) — VU (Vulnerable) — NT (Near Threatened) — LC (Least Concern) (from Conservation biology) -
Gregor Mendel, "father of modern genetics". (from History of biology) -
The frontispiece to Erasmus Darwin's evolution-themed poem The Temple of Nature shows a goddess pulling back the veil from nature (in the person of Artemis). Allegory and metaphor have often played an important role in the history of biology. (from History of biology) -
In Micrographia, Robert Hooke had applied the word cell to biological structures such as this piece of cork, but it was not until the 19th century that scientists considered cells the universal basis of life. (from History of biology) -
In the course of his travels, Alexander von Humboldt mapped the distribution of plants across landscapes and recorded a variety of physical conditions such as pressure and temperature. (from History of biology) -
2016 conservation indicator which includes the following indicators: marine protected areas, terrestrial biome protection (global and national), and species protection (global and national) (from Conservation biology) -
August Weismann's germ plasm theory. The hereditary material, the germ plasm, is confined to the gonads. Somatic cells (of the body) develop afresh in each generation from the germ plasm. (from History of genetics) -
Clay models of animal livers dating between the nineteenth and eighteenth centuries BCE, found in the royal palace at Mari (from History of biology) -
Diagram of Charles Darwin's pangenesis theory. Every part of the body emits tiny particles, gemmules, which migrate to the gonads and contribute to the fertilised egg and so to the next generation. The theory implied that changes to the body during an organism's life would be inherited, as proposed in Lamarckism. (from History of genetics) -
Brewing was an early example of biotechnology (from History of biotechnology) -
Synthetic insulin crystals synthesized using recombinant DNA technology (from History of biotechnology) -
Cabinets of curiosities, such as that of Ole Worm, were centers of biological knowledge in the early modern period, bringing organisms from across the world together in one place. Before the Age of Exploration, naturalists had little idea of the sheer scale of biological diversity. (from History of biology) -
The "central dogma of molecular biology" (originally a "dogma" only in jest) was proposed by Francis Crick in 1958. This is Crick's reconstruction of how he conceived of the central dogma at the time. The solid lines represent (as it seemed in 1958) known modes of information transfer, and the dashed lines represent postulated ones. (from History of biology) -
More conservation research is needed for understanding ecology and behaviour of the dhole in central China. (from Conservation biology) -
A pie chart image showing the relative biomass representation in a rain forest through a summary of children's perceptions from drawings and artwork (left), through a scientific estimate of actual biomass (middle), and by a measure of biodiversity (right). The biomass of social insects (middle) far outweighs the number of species (right). (from Conservation biology) -
De arte venandi, by Frederick II, Holy Roman Emperor, was an influential medieval natural history text that explored bird morphology. (from History of biology) -
Frontispiece to a 1644 version of the expanded and illustrated edition of Historia Plantarum, originally written by Theophrastus around 300 BC (from History of biology) -
Aristotle's model of transmission of movements from parents to child, and of form from the father. The model is not fully symmetric. (from History of genetics) -
Some biodiversity loss is more insidious than others due to systemic neglect. For example, sport killing and wanton waste of tons of native fishes from unregulated 21st century bowfishing in the United States. New conservation movements are needed to deter irreparable biodiversity loss to fragile freshwater ecosystems. (from Conservation biology) -
A Genentech-sponsored sign declaring South San Francisco to be "The Birthplace of Biotechnology." (from History of biotechnology) -
Wendell Stanley's crystallization of tobacco mosaic virus as a pure nucleoprotein in 1935 convinced many scientists that heredity might be explained purely through physics and chemistry. (from History of biology) -
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Innovative laboratory glassware and experimental methods developed by Louis Pasteur and other biologists contributed to the young field of bacteriology in the late 19th century. (from History of biology) -
Thomas Hunt Morgan's illustration of crossing over, part of the Mendelian-chromosome theory of heredity (from History of biology) -
Carefully engineered strains of the bacterium Escherichia coli are crucial tools in biotechnology as well as many other biological fields. (from History of biology) -
A biomedical work by Ibn al-Nafis, an early adherent of experimental dissection who discovered the pulmonary and coronary circulation (from History of biology) -
Thomas Hunt Morgan discovered sex linked inheritance of the white eyed mutation in the fruit fly Drosophila in 1910, implying the gene was on the sex chromosome. (from History of genetics) -
Mendelian inheritance states characteristics are discrete and are inherited by the parents. This image depicts a monohybrid cross and shows 3 generations: P1 generation (1), F1 generation (2), and F2 generation (3). Each organism inherits two alleles, one from each parent, that make up the genotype. The observed characteristic, the phenotype, is determined by the dominant allele in the genotype. In this monohybrid cross the dominant allele encodes for the colour red and the recessive allele encodes for the colour white. (from History of genetics)
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Did you know -
- ... that seeds of the fossil fruit Suciacarpa have fossil fungi inside them?
- ... that the fossil ant genus Agastomyrma was described from a single queen, and males of the fossil ant Proceratium eocenicum have a hair fringe?
- ... that less than 50 years after being discovered, Heterelmis stephani is now presumed extinct?
- ... that in 1981 Bobbi Campbell became the first person to publicly identify as a person living with HIV/AIDS?
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A complete list of scientific WikiProjects can be found here. See also Wikispecies, a Wikimedia project dedicated to classification of biological species.
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