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Astatotilapia Burtoni
''Astatotilapia burtoni'' is a species of fish in the family Cichlidae. It is found in Lake Tanganyika and its surrounding waterways, including parts of Burundi, Rwanda, Tanzania, and Zambia. Its natural habitats are rivers, intermittent rivers, swamps, freshwater lakes, freshwater marshes, intermittent freshwater marshes, and inland deltas. ''Astatotilapia burtoni'' has been used as a model organism to study the behaviors and physical systems of cichlids, including their development and embryogenesis. Moreover, the phylogenetic position of this particular species makes it an ideal model system for comparative genomic research. ''A. burtoni'' belongs under the haplochromines, which is the lineage of cichlids with the most species, and has been discovered to be a sister group to both the Lake Victoria region superflock (which has about 600 species) and the species flock of Lake Malawi (which has about 1,000 species). Social behavior Reversible male social roles The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Albert Günther
Albert Karl Ludwig Gotthilf Günther FRS, also Albert Charles Lewis Gotthilf Günther (3 October 1830 – 1 February 1914), was a German-born British zoologist, ichthyologist, and herpetologist. Günther is ranked the second-most productive reptile taxonomist (after George Albert Boulenger) with more than 340 reptile species described. Early life and career Günther was born in Esslingen in Swabia (Württemberg). His father was a ''Stiftungs-Commissar'' in Esslingen and his mother was Eleonora Nagel. He initially schooled at the Stuttgart Gymnasium. His family wished him to train for the ministry of the Lutheran Church for which he moved to the University of Tübingen. A brother shifted from theology to medicine, and he, too, turned to science and medicine at Tübingen in 1852. His first work was "''Ueber den Puppenzustand eines Distoma''". He graduated in medicine with an M.D. from Tübingen in 1858, the same year in which he published a handbook of zoology for students of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haplochromine
__NOTOC__ The haplochromine cichlids are a tribe of cichlids in subfamily Pseudocrenilabrinae called Haplochromini. This group includes the type genus (''Haplochromis'') plus a number of closely related genera such as ''Aulonocara'', ''Astatotilapia'', and '' Chilotilapia''. They are endemic to eastern, southern and northern Africa, except for '' Astatotilapia flaviijosephi'' in the '' Middle East''. A common name in a scientific context is East African cichlids – while they are not restricted to that region, they are the dominant Cichlidae there. This tribe was extensively studied by Ethelwynn Trewavas, who made major reviews in 1935 and 1989, at the beginning and at the end of her career in ichthyology. Even today, numerous new species are being described each year. The haplochromines were in older times treated as subfamily Haplochrominae, However, the great African radiation of pseudocrenilabrine cichlids is certainly not monophyletic without them, and thus they are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blood Plasma
Blood plasma is a light amber-colored liquid component of blood in which blood cells are absent, but contains proteins and other constituents of whole blood in suspension. It makes up about 55% of the body's total blood volume. It is the intravascular part of extracellular fluid (all body fluid outside cells). It is mostly water (up to 95% by volume), and contains important dissolved proteins (6–8%; e.g., serum albumins, globulins, and fibrinogen), glucose, clotting factors, electrolytes (, , , , , etc.), hormones, carbon dioxide (plasma being the main medium for excretory product transportation), and oxygen. It plays a vital role in an intravascular osmotic effect that keeps electrolyte concentration balanced and protects the body from infection and other blood-related disorders. Blood plasma is separated from the blood by spinning a vessel of fresh blood containing an anticoagulant in a centrifuge until the blood cells fall to the bottom of the tube. The blood plasm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Testosterone
Testosterone is the primary sex hormone and anabolic steroid in males. In humans, testosterone plays a key role in the development of male reproductive tissues such as testes and prostate, as well as promoting secondary sexual characteristics such as increased muscle and bone mass, and the growth of body hair. In addition, testosterone in both sexes is involved in health and well-being, including moods, behaviour, and in the prevention of osteoporosis. Insufficient levels of testosterone in men may lead to abnormalities including frailty and bone loss. Testosterone is a steroid from the androstane class containing a ketone and a hydroxyl group at positions three and seventeen respectively. It is biosynthesized in several steps from cholesterol and is converted in the liver to inactive metabolites. It exerts its action through binding to and activation of the androgen receptor. In humans and most other vertebrates, testosterone is secreted primarily by the testicles of m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cortisol
Cortisol is a steroid hormone, in the glucocorticoid class of hormones. When used as a medication, it is known as hydrocortisone. It is produced in many animals, mainly by the '' zona fasciculata'' of the adrenal cortex in the adrenal gland. It is produced in other tissues in lower quantities. It is released with a diurnal cycle and its release is increased in response to stress and low blood-glucose concentration. It functions to increase blood sugar through gluconeogenesis, to suppress the immune system, and to aid in the metabolism of fat, protein, and carbohydrates. It also decreases bone formation. Many of these functions are carried out by cortisol binding to glucocorticoid or mineralocorticoid receptors inside the cell, which then bind to DNA to impact gene expression. Health effects Metabolic response Metabolism of glucose In general, cortisol stimulates gluconeogenesis (the synthesis of 'new' glucose from non-carbohydrate sources, which occurs mainly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hormone
A hormone (from the Greek participle , "setting in motion") is a class of signaling molecules in multicellular organisms that are sent to distant organs by complex biological processes to regulate physiology and behavior. Hormones are required for the correct development of animals, plants and fungi. Due to the broad definition of a hormone (as a signaling molecule that exerts its effects far from its site of production), numerous kinds of molecules can be classified as hormones. Among the substances that can be considered hormones, are eicosanoids (e.g. prostaglandins and thromboxanes), steroids (e.g. oestrogen and brassinosteroid), amino acid derivatives (e.g. epinephrine and auxin), protein or peptides (e.g. insulin and CLE peptides), and gases (e.g. ethylene and nitric oxide). Hormones are used to communicate between organs and tissues. In vertebrates, hormones are responsible for regulating a variety of physiological processes and behavioral activities such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eyebar (fish)
In structural engineering and construction, an eyebar is a straight bar, usually of metal, with a hole ("eye") at each end for fixing to other components. Eyebars are used in structures such as bridges, in settings in which only tension, and never compression, is applied. Also referred to as "pin- and eyebar construction" in instances where pins are being used. Structure A closed eyebar will typically have a rectangular cross section of constant thickness throughout its length and a constant width for all but the ends. The ends will transition to a wider part that is terminated by a rounded end. In the center of this end will be a hole which will receive a cylindrical pin, which may have provision to accept one or more nuts or bolts. If of round cross section the bar will typically be end-forged to create a head, which is then flatted by additional forging. The head may then be machined to a precise thickness and flatness. An alternative method for using round bar is to form ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gonads
A gonad, sex gland, or reproductive gland is a mixed gland that produces the gametes and sex hormones of an organism. Female reproductive cells are egg cells, and male reproductive cells are sperm. The male gonad, the testicle, produces sperm in the form of spermatozoa. The female gonad, the ovary, produces egg cells. Both of these gametes are haploid cells. Some hermaphroditic animals have a type of gonad called an ovotestis. Evolution It is hard to find a common origin for gonads, but gonads most likely evolved independently several times. Regulation The gonads are controlled by luteinizing hormone and follicle-stimulating hormone, produced and secreted by gonadotropes or gonadotrophins in the anterior pituitary gland. This secretion is regulated by gonadotropin-releasing hormone produced in the hypothalamus. Development Gonads start developing as a common primordium (an organ in the earliest stage of development), in the form of genital ridges, which are only la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Territory (animal)
In ethology, territory is the sociographical area that an animal consistently defends against conspecific competition (or, occasionally, against animals of other species) using agonistic behaviors or (less commonly) real physical aggression. Animals that actively defend territories in this way are referred to as being territorial or displaying territorialism. Territoriality is only shown by a minority of species. More commonly, an individual or a group of animals occupies an area that it habitually uses but does not necessarily defend; this is called its home range. The home ranges of different groups of animals often overlap, and in these overlap areas the groups tend to avoid each other rather than seeking to confront and expel each other. Within the home range there may be a ''core area'' that no other individual group uses, but, again, this is as a result of avoidance. Function The ultimate function of animals inhabiting and defending a territory is to increase the indi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenotypes
In genetics, the phenotype () is the set of observable characteristics or phenotypic trait, traits of an organism. The term covers the organism's morphology (biology), morphology or physical form and structure, its Developmental biology, developmental processes, its biochemical and physiological properties, its behavior, and the products of behavior. An organism's phenotype results from two basic factors: the Gene expression, expression of an organism's genetic code, or its genotype, and the influence of environmental factors. Both factors may interact, further affecting phenotype. When two or more clearly different phenotypes exist in the same population of a species, the species is called Polymorphism (biology), polymorphic. A well-documented example of polymorphism is Labrador Retriever coat colour genetics, Labrador Retriever coloring; while the coat color depends on many genes, it is clearly seen in the environment as yellow, black, and brown. Richard Dawkins in 1978 a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lake Malawi
Lake Malawi, also known as Lake Nyasa in Tanzania and Lago Niassa in Mozambique, is an African Great Lake and the southernmost lake in the East African Rift system, located between Malawi, Mozambique and Tanzania. It is the fifth largest fresh water lake in the world by volume, the ninth largest lake in the world by area—and the third largest and second deepest lake in Africa. Lake Malawi is home to more species of fish than any other lake in the world, including at least 700 species of cichlids.Turner, Seehausen, Knight, Allender, and Robinson (2001). "How many species of cichlid fishes are there in African lakes?" ''Molecular Ecology'' 10: 793–806. The Mozambique portion of the lake was officially declared a reserve by the Government of Mozambique on June 10, 2011,WWF (10 June 2011)"Mozambique’s Lake Niassa declared reserve and Ramsar site"Retrieved 17 July 2014. while in Malawi a portion of the lake is included in Lake Malawi National Park. Lake Malawi is a mer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
