Blepharisma Seshachari
''Blepharisma'' is a genus of unicellular ciliate protists found in fresh and salt water. The group includes about 40 accepted species, and many sub-varieties and strains. While species vary considerably in size and shape, most are easily identified by their red or pinkish color, which is caused by granules of the pigment blepharismin. All members of the genus possess a long series of membranelles on the left side of the oral groove, and an "undulating membrane" (a structure resembling a flap, scarf or small sail, composed of long cilia fused together as a single sheet) on the right side of the peristome, toward the posterior. Certain species of ''Blepharisma'' have served as model organisms for scientific research. Since some varieties are easily cultured and readily available from scientific supply houses, they are a common object of study in school science classes. Appearance ''Blepharisma'' may be as small as 50 micrometres in length, or as large as 1 mm (though nor ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Blepharisma Japonicum
''Blepharisma japonicum'' is a species of protozoan that can be found either in water or soil in Japan. Description The body of an organism is elongated and ovoided. It has a curved anterior apex that is over the peristome. It has a cytostome which is a two-layered undulating membrane, on the right front edge, and also contractile vacuole A contractile vacuole (CV) is a sub-cellular structure (organelle) involved in osmoregulation. It is found predominantly in protists, including unicellular algae. It was previously known as pulsatile or pulsating vacuole. Overview The contrac ... with cytopyge terminal. It is either brown or rose-coloured. Conjugation ''Blepharisma japonicum'' produces sexual pheromones that promote conjugation. There are two mating types (I and II), each type excreting a specific pheromone (termed gamone 1 and gamone 2, respectively). When sexually mature mating-type I cells are moderately starved, they autonomously produce and secrete gamone I. Gam ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Meiosis
Meiosis () is a special type of cell division of germ cells in sexually-reproducing organisms that produces the gametes, the sperm or egg cells. It involves two rounds of division that ultimately result in four cells, each with only one copy of each chromosome (haploid). Additionally, prior to the division, genetic material from the paternal and maternal copies of each chromosome is crossed over, creating new combinations of code on each chromosome. Later on, during fertilisation, the haploid cells produced by meiosis from a male and a female will fuse to create a zygote, a cell with two copies of each chromosome. Errors in meiosis resulting in aneuploidy (an abnormal number of chromosomes) are the leading known cause of miscarriage and the most frequent genetic cause of developmental disabilities. In meiosis, DNA replication is followed by two rounds of cell division to produce four daughter cells, each with half the number of chromosomes as the original parent cell. ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Blepharisma Hyalinum - 160x - Länge 200µ (10388446276)
''Blepharisma'' is a genus of unicellular ciliate protists found in fresh and salt water. The group includes about 40 accepted species, and many sub-varieties and strains. While species vary considerably in size and shape, most are easily identified by their red or pinkish color, which is caused by granules of the pigment blepharismin. All members of the genus possess a long series of membranelles on the left side of the oral groove, and an "undulating membrane" (a structure resembling a flap, scarf or small sail, composed of long cilia fused together as a single sheet) on the right side of the peristome, toward the posterior. Certain species of ''Blepharisma'' have served as model organisms for scientific research. Since some varieties are easily cultured and readily available from scientific supply houses, they are a common object of study in school science classes. Appearance ''Blepharisma'' may be as small as 50 micrometres in length, or as large as 1 mm (though no ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Plasma Membrane
The cell membrane (also known as the plasma membrane or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of a cell from the outside environment (the extracellular space). The cell membrane consists of a lipid bilayer, made up of two layers of phospholipids with cholesterols (a lipid component) interspersed between them, maintaining appropriate membrane fluidity at various temperatures. The membrane also contains membrane proteins, including integral proteins that span the membrane and serve as membrane transporters, and peripheral proteins that loosely attach to the outer (peripheral) side of the cell membrane, acting as enzymes to facilitate interaction with the cell's environment. Glycolipids embedded in the outer lipid layer serve a similar purpose. The cell membrane controls the movement of substances in and out of a cell, being selectively permeable to ions and organic molecu ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Photophobia (biology)
In biology, photophobia (adjective: photophobic) is negative response to light. Photophobia is a behavior demonstrated by insects or other animals which seek to stay out of the light. In botany, the term photophobia/photophobic describes shade-loving plants (sciophytes) that thrive in low light conditions. Photophobia (or photophobic response) may also refer to a negative phototaxis or phototropism In biology, phototropism is the growth of an organism in response to a light stimulus. Phototropism is most often observed in plants, but can also occur in other organisms such as fungi. The cells on the plant that are farthest from the ligh ... response. References Physiology {{biology-stub ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Tetrahymena
''Tetrahymena'' is a genus of free-living ciliates, examples of unicellular eukaryotes. The genus Tetrahymena is the most widely studied member of its phylum. It can produce, store and react with different types of hormones. ''Tetrahymena'' cells can recognize both related and hostile cells. They can also switch from commensalistic to pathogenic modes of survival. They are common in freshwater lakes, ponds, and streams. ''Tetrahymena'' species used as model organisms in biomedical research are '' T. thermophila'' and '' T. pyriformis''. ''T. thermophila'': a model organism in experimental biology As a ciliated protozoan, ''Tetrahymena thermophila'' exhibits nuclear dimorphism: two types of cell nuclei. They have a bigger, non-germline macronucleus and a small, germline micronucleus in each cell at the same time and these two carry out different functions with distinct cytological and biological properties. This unique versatility allows scientists to use ''Tetrahyme ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Colpidium Colpoda
''Colpidium colpoda'' are free-living ciliates commonly found in many freshwater environments including streams, rivers, lakes and ponds across the world. ''Colpidium colpoda'' is also frequently found inhabiting wastewater treatment plants. This species is used as an indicator of water quality and waste treatment plant performance. History and physical characteristics The first record of ''Colpidium colpoda'' was in 1829 by Mathaeo Losana, who placed it in the genus ''Paramaecia''. It was more thoroughly described by Christian Gottfried Ehrenberg in his two volume publication ''Die Infusionsthierchen als vollkommene Organismen'' (which roughly translates to “The Infusoria as Perfect Organisms”) in 1838. The species was described in detail by Ganner and Foissner in 1989. ''C. colpoda'' is considered an intermediate sized ciliate, typically between 50 and 150 μm long. The cell is roughly oval or kidney-shaped in profile, with a distinct concavity on the Anatomical terms of l ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Rotifer
The rotifers (, from Latin 'wheel' and 'bearing'), sometimes called wheel animals or wheel animalcules, make up a phylum (Rotifera ) of microscopic and near-microscopic Coelom#Pseudocoelomates, pseudocoelomate animals. They were first described by John Harris (writer), Rev. John Harris in 1696, and other forms were described by Antonie van Leeuwenhoek in 1703. Most rotifers are around long (although their size can range from to over ), and are common in freshwater environments throughout the world with a few Seawater, saltwater species. Some rotifers are free swimming and truly planktonic, others move by inchworming along a substrate, and some are Sessility (zoology), sessile, living inside tubes or gelatinous holdfast (biology), holdfasts that are attached to a substrate. About 25 species are colonial (e.g., ''Sinantherina semibullata''), either sessile or planktonic. Rotifers are an important part of the freshwater zooplankton, being a major foodsource and with many specie ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Flagellate
A flagellate is a cell or organism with one or more whip-like appendages called flagella. The word ''flagellate'' also describes a particular construction (or level of organization) characteristic of many prokaryotes and eukaryotes and their means of motion. The term presently does not imply any specific relationship or classification of the organisms that possess flagella. However, several derivations of the term "flagellate" (such as " dinoflagellate" and " choanoflagellate") are more formally characterized. Form and behavior Flagella in eukaryotes are supported by microtubules in a characteristic arrangement, with nine fused pairs surrounding two central singlets. These arise from a basal body. In some flagellates, flagella direct food into a cytostome or mouth, where food is ingested. Flagella role in classifying eukaryotes. Among protoctists and microscopic animals, a flagellate is an organism with one or more flagella. Some cells in other animals may be flage ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Bacteria
Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit the air, soil, water, Hot spring, acidic hot springs, radioactive waste, and the deep biosphere of Earth's crust. Bacteria play a vital role in many stages of the nutrient cycle by recycling nutrients and the nitrogen fixation, fixation of nitrogen from the Earth's atmosphere, atmosphere. The nutrient cycle includes the decomposition of cadaver, dead bodies; bacteria are responsible for the putrefaction stage in this process. In the biological communities surrounding hydrothermal vents and cold seeps, extremophile bacteria provide the nutrients needed to sustain life by converting dissolved compounds, suc ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Outcrossing
Out-crossing or out-breeding is the technique of crossing between different breeds. This is the practice of introducing distantly related genetic material into a breeding line, thereby increasing genetic diversity. Outcrossing in animals Outcrossing can be a useful technique in animal breeding. The outcrossing breeder intends to remove the traits by using "new blood." With dominant traits, one can still see the expression of the traits and can remove those traits, whether one outcrosses, line breeds or inbreeds. With recessive traits, outcrossing allows for the recessive traits to migrate across a population. Many traits are Mendelian and therefore exhibit a more complicated intermediate phenotype. The outcrossing breeder then may have individuals that have many deleterious genes that may be expressed by subsequent inbreeding. There is now a gamut of deleterious genes within each individual in many dog breeds. Increasing the variation of genes or alleles within the gene poo ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |