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Key Innovation
In evolutionary biology, a key innovation, also known as an adaptive breakthrough or key adaptation, is a novel phenotypic trait that allows subsequent radiation and success of a taxonomic group. Typically they bring new abilities that allows the taxa to rapidly diversify and invade niches that were not previously available. The phenomenon helps to explain how some taxa are much more diverse and have many more species than their sister taxa. The term was first used in 1949 by Alden H. Miller who defined it as "key adjustments in the morphological and physiological mechanism which are essential to the origin of new major groups", although a broader, contemporary definition holds that "a key innovation is an evolutionary change in individual traits that is causally linked to an increased diversification rate in the resulting clade". The theory of key innovations has come under attack because it is hard to test in a scientific manner, but there is evidence to support the idea. Mechan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evolutionary Biology
Evolutionary biology is the subfield of biology that studies the evolutionary processes (natural selection, common descent, speciation) that produced the diversity of life on Earth. It is also defined as the study of the history of life forms on Earth. Evolution is based on the theory that all species are related and they gradually change over time. In a population, the genetic variations affect the physical characteristics i.e. phenotypes of an organism. These changes in the phenotypes will be an advantage to some organisms, which will then be passed onto their offspring. Some examples of evolution in species over many generations are the Peppered Moth and Flightless birds. In the 1930s, the discipline of evolutionary biology emerged through what Julian Huxley called the modern synthesis of understanding, from previously unrelated fields of biological research, such as genetics and ecology, systematics, and paleontology. The importance of studying Evolutionary biology is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eocene
The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', "dawn") and (''kainós'', "new") and refers to the "dawn" of modern ('new') fauna that appeared during the epoch. The Eocene spans the time from the end of the Paleocene Epoch to the beginning of the Oligocene Epoch. The start of the Eocene is marked by a brief period in which the concentration of the carbon isotope Carbon-13, 13C in the atmosphere was exceptionally low in comparison with the more common isotope Carbon-12, 12C. The end is set at a major extinction event called the ''Grande Coupure'' (the "Great Break" in continuity) or the Eocene–Oligocene extinction event, which may be related to the impact of one or more large bolides in Popigai impact structure, Siberia and in what is now ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adaptive Radiation
In evolutionary biology, adaptive radiation is a process in which organisms diversify rapidly from an ancestral species into a multitude of new forms, particularly when a change in the environment makes new resources available, alters biotic interactions or opens new environmental niches. Starting with a single ancestor, this process results in the speciation and phenotypic adaptation of an array of species exhibiting different morphological and physiological traits. The prototypical example of adaptive radiation is finch speciation on the Galapagos ("Darwin's finches"), but examples are known from around the world. Characteristics Four features can be used to identify an adaptive radiation: #A common ancestry of component species: specifically a ''recent'' ancestry. Note that this is not the same as a monophyly in which ''all'' descendants of a common ancestor are included. #A phenotype-environment correlation: a ''significant'' association between environments and the morp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sternum
The sternum or breastbone is a long flat bone located in the central part of the chest. It connects to the ribs via cartilage and forms the front of the rib cage, thus helping to protect the heart, lungs, and major blood vessels from injury. Shaped roughly like a necktie, it is one of the largest and longest flat bones of the body. Its three regions are the manubrium, the body, and the xiphoid process. The word "sternum" originates from the Ancient Greek στέρνον (stérnon), meaning "chest". Structure The sternum is a narrow, flat bone, forming the middle portion of the front of the chest. The top of the sternum supports the clavicles (collarbones) and its edges join with the costal cartilages of the first two pairs of ribs. The inner surface of the sternum is also the attachment of the sternopericardial ligaments. Its top is also connected to the sternocleidomastoid muscle. The sternum consists of three main parts, listed from the top: * Manubrium * Body (gladiolus) * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ossification
Ossification (also called osteogenesis or bone mineralization) in bone remodeling is the process of laying down new bone material by cells named osteoblasts. It is synonymous with bone tissue formation. There are two processes resulting in the formation of normal, healthy bone tissue: Intramembranous ossification is the direct laying down of bone into the primitive connective tissue ( mesenchyme), while endochondral ossification involves cartilage as a precursor. In fracture healing, endochondral osteogenesis is the most commonly occurring process, for example in fractures of long bones treated by plaster of Paris, whereas fractures treated by open reduction and internal fixation with metal plates, screws, pins, rods and nails may heal by intramembranous osteogenesis. Heterotopic ossification is a process resulting in the formation of bone tissue that is often atypical, at an extraskeletal location. Calcification is often confused with ossification. Calcification is sy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cerebellum
The cerebellum (Latin for "little brain") is a major feature of the hindbrain of all vertebrates. Although usually smaller than the cerebrum, in some animals such as the mormyrid fishes it may be as large as or even larger. In humans, the cerebellum plays an important role in motor control. It may also be involved in some cognition, cognitive functions such as attention and language as well as emotion, emotional control such as regulating fear and pleasure responses, but its movement-related functions are the most solidly established. The human cerebellum does not initiate movement, but contributes to Motor coordination, coordination, precision, and accurate timing: it receives input from sensory systems of the spinal cord and from other parts of the brain, and integrates these inputs to fine-tune motor activity. Cerebellar damage produces disorders in Fine motor skill, fine movement, Equilibrioception, equilibrium, Human positions, posture, and motor learning in humans. Anatomica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ernst Mayr
Ernst Walter Mayr (; 5 July 1904 – 3 February 2005) was one of the 20th century's leading evolutionary biologists. He was also a renowned Taxonomy (biology), taxonomist, tropical explorer, ornithologist, Philosophy of biology, philosopher of biology, and History of science, historian of science. His work contributed to the conceptual revolution that led to the Modern synthesis (20th century), modern evolutionary synthesis of Gregor Mendel, Mendelian genetics, systematics, and Charles Darwin, Darwinian evolution, and to the development of the Species, biological species concept. Although Charles Darwin and others posited that multiple species could evolve from a single common ancestor, the mechanism by which this occurred was not understood, creating the ''species problem''. Ernst Mayr approached the problem with a new definition for species. In his book ''Systematics and the Origin of Species'' (1942) he wrote that a species is not just a group of Morphology (biology), morph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pollen
Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametophytes during the process of their movement from the stamens to the pistil of flowering plants, or from the male cone to the female cone of gymnosperms. If pollen lands on a compatible pistil or female cone, it germinates, producing a pollen tube that transfers the sperm to the ovule containing the female gametophyte. Individual pollen grains are small enough to require magnification to see detail. The study of pollen is called palynology and is highly useful in paleoecology, paleontology, archaeology, and forensics. Pollen in plants is used for transferring haploid male genetic material from the anther of a single flower to the stigma of another in cross-pollination. In a case of self-pollination, this process takes place from the anth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pollinators
A pollinator is an animal that moves pollen from the male anther of a flower to the female stigma of a flower. This helps to bring about fertilization of the ovules in the flower by the male gametes from the pollen grains. Insects are the major pollinators of most plants, and insect pollinators include all families of bees and most families of aculeate wasps; ants; many families of flies; many lepidopterans (both butterflies and moths); and many families of beetles. Vertebrates, mainly bats and birds, but also some non-bat mammals (monkeys, lemurs, possums, rodents) and some lizards pollinate certain plants. Among the pollinating birds are hummingbirds, honeyeaters and sunbirds with long beaks; they pollinate a number of deep-throated flowers. Humans may also carry out artificial pollination. A pollinator is different from a pollenizer, a plant that is a source of pollen for the pollination process. Background Plants fall into pollination syndromes that reflect the type of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nectar
Nectar is a sugar-rich liquid produced by plants in glands called nectaries or nectarines, either within the flowers with which it attracts pollinating animals, or by extrafloral nectaries, which provide a nutrient source to animal mutualists, which in turn provide herbivore protection. Common nectar-consuming pollinators include mosquitoes, hoverflies, wasps, bees, butterflies and moths, hummingbirds, honeyeaters and bats. Nectar plays a crucial role in the foraging economics and evolution of nectar-eating species; for example, nectar foraging behavior is largely responsible for the divergent evolution of the African honey bee, ''A. m. scutellata'' and the western honey bee. Nectar is an economically important substance as it is the sugar source for honey. It is also useful in agriculture and horticulture because the adult stages of some predatory insects feed on nectar. For example, a number of parasitoid wasps (e.g. the social wasp species ''Apoica flavissima'') rely ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aquilegia
''Aquilegia'' (common names: granny's bonnet, columbine) is a genus of about 60–70 species of perennial plants that are found in meadows, woodlands, and at higher altitudes throughout the Northern Hemisphere, known for the spurred petals Puzey, J.R., Gerbode, S.J., Hodges, S.A., Kramer, E.M., Mahadevan, L. (2011) Evolution of ''Aquilegia'' spur length diversity through changes in cell anisotropy. Proceedings of the Royal Society B. of their flowers. Etymology The genus name Aquilegia comes from the Latin “Aquila”, or “eagle”; this is in obvious reference to the spurred, “hook” shapes within the blooms, that many gardeners say resemble an eagle's talons. Description Perennial herbs, with woody, erect stock, roots forming thick rhizomes. The basal leaves are compound, 1–3 ternate, blades 3-lobed -partite, and lobes lobulate and obtuse. The cauline leaves are similar to the basal ones, while the upper ones are bract like. The hermaphrodite (bisexual) flowers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aquilegia Columbine Magpie Cultivar 2
''Aquilegia'' (common names: granny's bonnet, columbine) is a genus of about 60–70 species of perennial plants that are found in meadows, woodlands, and at higher altitudes throughout the Northern Hemisphere, known for the spurred petals Puzey, J.R., Gerbode, S.J., Hodges, S.A., Kramer, E.M., Mahadevan, L. (2011) Evolution of ''Aquilegia'' spur length diversity through changes in cell anisotropy. Proceedings of the Royal Society B. of their flowers. Etymology The genus name Aquilegia comes from the Latin “Aquila”, or “eagle”; this is in obvious reference to the spurred, “hook” shapes within the blooms, that many gardeners say resemble an eagle's talons. Description Perennial herbs, with woody, erect stock, roots forming thick rhizomes. The basal leaves are compound, 1–3 ternate, blades 3-lobed -partite, and lobes lobulate and obtuse. The cauline leaves are similar to the basal ones, while the upper ones are bract like. The hermaphrodite (bisexual) flowers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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