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Sperm Competition
Sperm competition is the competitive process between Spermatozoon, spermatozoa of two or more different males to fertility, fertilize the same Egg cell, egg during sexual reproduction. Competition can occur when females have multiple potential mating partners. Greater choice and variety of mates increases a female's chance to produce more viable offspring. However, multiple mates for a female means each individual male has decreased chances of producing offspring. Sperm competition is an evolutionary pressure on males, and has led to the development of adaptations to increase male's chance of reproductive success. Sperm competition results in a sexual conflict between males and females. Males have evolved several defensive tactics including: mate-guarding, mating plugs, and releasing toxic seminal substances to reduce female re-mating tendencies to cope with sperm competition. Offensive tactics of sperm competition involve direct interference by one male on the reproductive succes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sperm Stained
Sperm (: sperm or sperms) is the male reproductive Cell (biology), cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there is a larger, female reproductive cell and a smaller, male one). Animals produce motile sperm with a tail known as a flagellum, which are known as spermatozoa, while some red algae and fungi produce non-motile sperm cells, known as spermatia. Flowering plants contain non-motile sperm inside pollen, while some more basal plants like ferns and some gymnosperms have motile sperm. Sperm cells form during the process known as spermatogenesis, which in amniotes (reptiles and mammals) takes place in the seminiferous tubules of the testicles. This process involves the production of several successive sperm cell precursors, starting with spermatogonia, which Cellular differentiation, differentiate into spermatocytes. The spermatocytes then undergo meiosis, reducing their Ploidy, chromosome number by half, which produces spermatids. The sper ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adaptations
In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the population during that process. Thirdly, it is a phenotypic trait or adaptive trait, with a functional role in each individual organism, that is maintained and has evolved through natural selection. Historically, adaptation has been described from the time of the ancient Greek philosophers such as Empedocles and Aristotle. In 18th and 19th-century natural theology, adaptation was taken as evidence for the existence of a deity. Charles Darwin and Alfred Russel Wallace proposed instead that it was explained by natural selection. Adaptation is related to biological fitness, which governs the rate of evolution as measured by changes in allele frequencies. Often, two or more species co-adapt and co-evolve as they develop adaptations tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Accessory Gland
This glossary of entomology describes terms used in the formal study of insect species by entomologists. A–C A synthetic chlorinated hydrocarbon insecticide Insecticides are pesticides used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. The major use of insecticides is in agriculture, but they are also used in home and garden settings, i ..., toxic to vertebrates. Though its phytotoxicity is low, solvents in some formulations may damage certain crops. cf. the related Dieldrin, Endrin, Isodrin * D–F A synthetic chlorinated hydrocarbon insecticide, toxic to vertebrates. cf. the related Aldrin, Endrin, Isodrin A synthetic chlorinated hydrocarb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drosophila Melanogaster
''Drosophila melanogaster'' is a species of fly (an insect of the Order (biology), order Diptera) in the family Drosophilidae. The species is often referred to as the fruit fly or lesser fruit fly, or less commonly the "vinegar fly", "pomace fly", or "banana fly". In the wild, ''D. melanogaster'' are attracted to rotting fruit and fermenting beverages, and are often found in orchards, kitchens and pubs. Starting with Charles W. Woodworth's 1901 proposal of the use of this species as a model organism, ''D. melanogaster'' continues to be widely used for biological research in genetics, physiology, microbial pathogenesis, and Life history theory, life history evolution. ''D. melanogaster'' was the first animal to be Fruit flies in space, launched into space in 1947. As of 2017, six Nobel Prizes have been awarded to drosophilists for their work using the insect. ''Drosophila melanogaster'' is typically used in research owing to its rapid life cycle, relatively simple genetics with on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drosophila Mettleri
''Drosophila metlerri'', commonly known as the Sonoran Desert fly, is a fly in the genus ''Drosophila''. The species is found in North America and is most concentrated along the southern coast of California and in Mexico. ''D. mettleri'' are dependent on plant hosts, namely, the saguaro and Pachycereus pringlei, cardon cacti. Thus, they are most prevalent in arid, desert conditions. It is able to detoxify chemicals found in the rotting liquid of cacti hosts, which allows it to use otherwise lethal soil as a nesting site. ''D. mettleri'' was discovered in San Felipe, Baja California in October 1961 during an experiment where banana was used to attract several species of ''Drosophila''. Due to physical geographic barriers between Sonoran Desert flies, gene flow explains speciation. It breeds in soil moistened by liquid excreted by rotting cacti and on necrotic patches. The liquid found in rotting cacti patches serves as a nutrient source for ''D. mettleri'' larvae, despite it cont ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linoleic Acid
Linoleic acid (LA) is an organic compound with the formula . Both alkene groups () are ''cis''. It is a fatty acid sometimes denoted 18:2 (n−6) or 18:2 ''cis''-9,12. A linoleate is a salt or ester of this acid. Linoleic acid is a polyunsaturated, omega−6 fatty acid. It is a colorless liquid that is virtually insoluble in water but soluble in many organic solvents. It typically occurs in nature as a triglyceride (ester of glycerin) rather than as a free fatty acid. It is one of two essential fatty acids for humans, who must obtain it through their diet, and the most essential, because the body uses it as a base to make the others. The word "linoleic" derives , reflecting the fact that it was first isolated from linseed oil. History In 1844, F. Sacc, working at the laboratory of Justus von Liebig Justus ''Freiherr'' von Liebig (12 May 1803 – 18 April 1873) was a Germans, German scientist who made major contributions to the theory, practice, and pedagogy of che ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bumblebee
A bumblebee (or bumble bee, bumble-bee, or humble-bee) is any of over 250 species in the genus ''Bombus'', part of Apidae, one of the bee families. This genus is the only Extant taxon, extant group in the tribe Bombini, though a few extinct related genera (e.g., ''Calyptapis'') are known from fossils. They are found primarily in the Northern Hemisphere, although they are also found in South America, where a few lowland tropical species have been identified. European bumblebees have also been introduced to New Zealand and Tasmania. Female bumblebees can sting repeatedly, but generally ignore humans and other animals. Most bumblebees are eusociality, social insects that form colony (biology), colonies with a single queen. The colonies are smaller than those of honey bees, growing to as few as 50 individuals in a nest. Psithyrus, Cuckoo bumblebees are brood parasite, brood parasitic and do not make nests or form colonies; their queens aggressively invade the nests of other bumble ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copulatory Plug
A mating plug, also known as a copulation plug, vaginal plug, sperm plug, or sphragis (Latin, from , "a seal"), is a gelatinous secretion used in the mating of some species. It is deposited by a male into a female genital tract, such as the vagina, and later hardens into a plug or glues the tract together. While females can expel the plugs afterwards, the male's sperm still gets a time advantage in getting to the egg, which is often the deciding factor in fertilization. The mating plug plays an important role in sperm competition and may serve as an alternative and more advantageous strategy to active mate guarding. In some species, such a passive mate-guarding strategy may reduce selection on large male size. Such a strategy may be advantageous because it would allow a male to increase reproductive success by spending more time pursuing new female mates rather than active mate guarding. Composition The mating plug of the '' Bombus terrestris'' was chemically analyzed and fou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drosophila Melanogaster - Side (aka)
''Drosophila'' (), from Ancient Greek δρόσος (''drósos''), meaning "dew", and φίλος (''phílos''), meaning "loving", is a genus of fly, belonging to the family Drosophilidae, whose members are often called "small fruit flies" or pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many species to linger around overripe or rotting fruit. They should not be confused with the Tephritidae, a related family, which are also called fruit flies (sometimes referred to as "true fruit flies"); tephritids feed primarily on unripe or ripe fruit, with many species being regarded as destructive agricultural pests, especially the Mediterranean fruit fly. One species of ''Drosophila'' in particular, '' Drosophila melanogaster'', has been heavily used in research in genetics and is a common model organism in developmental biology. The terms "fruit fly" and "''Drosophila''" are often used synonymously with ''D. melanogaster'' in modern biological litera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indianmeal Moth 2009
Maize meal is a meal (coarse flour) ground from dried maize. It is a common staple food and is ground to coarse, medium, and fine consistencies, but it is not as fine as wheat flour can be.Herbst, Sharon, ''Food Lover's Companion'', Third Edition, Pg. 165, Barrons Educational Series Inc, 2001 In Mexico and Louisiana, very finely ground cornmeal is referred to as corn flour. When fine cornmeal is made from maize that has been soaked in an alkaline solution, e.g., limewater (a process known as nixtamalization), it is called masa harina (or masa flour), which is used for making arepas, tamales, and tortillas. Boiled cornmeal is called polenta in Italy and is also a traditional dish and bread substitute in Romania. Types There are various types of cornmeal: *''Blue cornmeal'' is light blue or violet in color. It is ground from whole blue corn and has a sweet flavor. The cornmeal consists of dried corn kernels that have been ground into a fine or medium texture. *''Steel-ground ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extra-pair Copulation
Extra-pair copulation (EPC) is a mating behaviour in monogamous species. Monogamy is the practice of having only one sexual partner at any one time, forming a long-term bond and combining efforts to raise offspring together; mating outside this pairing is extra-pair copulation. Across the animal kingdom, extra-pair copulation is common in monogamous species, and only a very few pair-bonded species are thought to be exclusively sexually monogamous. EPC in the animal kingdom has mostly been studied in birds and mammals. Possible benefits of EPC can be investigated within non-human species, such as birds. For males, a number of theories are proposed to explain extra-pair copulations. One such hypothesis is that males maximise their reproductive success by copulating with as many females as possible outside of a pair bond relationship because their parental investment is lower, meaning they can copulate and leave the female with minimum risk to themselves. Females, on the other hand ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neolamprologus Pulcher
''Neolamprologus pulcher'' is a species of cichlid endemic to Lake Tanganyika where it prefers locations with plenty of sedimentation. The common names for ''N. pulcher'' include daffodil cichlid, fairy cichlid, princess of Zambia and lyretail cichlid. This species can reach a length of TL. It can also be found in the aquarium trade. Taxonomy and phylogeny Previously, it was believed that ''N. pulcher'' and ''N. brichardi'' were two distinct species. Now they are considered the same species, the only difference being that Neolamprologus brichardi has a black stripe running from its eye to its gill cover and a yellow spot just above it, both of which are absent in N. pulcher. Because Neolamprologus pulcher is the older of the two scientific names, the rules of scientific nomenclature would make this the correct name for the species. The daffodil cichlid, when it was still known as N. brichardi, was named after Pierre Brichard, a Belgian who set up a collection station, for t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
