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Koliella Spiculiformis
''Koliella'' is a genus of green algae in the order Prasiolales. Members of this genus are found in freshwater plankton, but some are also found on snow and ice. The genus name of ''Koliella'' is in honour of Erszébet (Elizabet) Kol (1897-1980), who was a Hungarian botanist (Mycology and Algology), who worked at the Hungarian National Museum in Budapest. The genus was circumscribed by František Hindák in Nova Hedwigia vol.6 (issues 1/2) on page 99 in 1963. Description ''Koliella'' consists of straight or curved spindle-shaped or needle-shaped cells. The apices may be rounded, obtuse, acute, or sharply pointed. Cells contain a single parietal chloroplast lining the inside of the cell, which may be straight or spiraled; a pyrenoid may be present or absent. Oil droplets are also present within the cell. ''Koliella'' reproduces vegetatively by cell division; cells usually detach after division, but may occasionally be found in short chains. It is similar to a number of fusiform ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrenoid
Pyrenoids are sub-cellular phase-separated micro-compartments found in chloroplasts of many algae,Giordano, M., Beardall, J., & Raven, J. A. (2005). CO2 concentrating mechanisms in algae: mechanisms, environmental modulation, and evolution. ''Annu. Rev. Plant Biol.'', 56, 99-131. and in a single group of land plants, the hornworts.Villarreal, J. C., & Renner, S. S. (2012) Hornwort pyrenoids, carbon-concentrating structures, evolved and were lost at least five times during the last 100 million years. ''Proceedings of the National Academy of Sciences'',109(46), 1873-1887. Pyrenoids are associated with the operation of a carbon-concentrating mechanism (CCM). Their main function is to act as centres of carbon dioxide (CO2) fixation, by generating and maintaining a CO2-rich environment around the photosynthesis, photosynthetic enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO). Pyrenoids therefore seem to have a role analogous to that of carboxysomes in cyanobacteria. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trebouxiophyceae Genera
The Trebouxiophyceae, also known as trebouxiophytes, are a class of green algae, in the division Chlorophyta. Members of this class are single-celled, colonial, or multicellular and are found in freshwater, terrestrial or marine habitats worldwide. Many taxa in the Trebouxiophyceae form symbiotic relationships with other organisms; in particular, the majority of phycobionts within lichens are trebouxiophytes. A number of taxa have also lost the ability to photosynthesize, and have evolved to become parasitic; examples include '' Prototheca'' and '' Helicosporidium''. Trebouxiophyceae was originally defined by ultrastructural characteristics, but is now generally circumscribed based on phylogenetics, particularly based on the 18S rDNA locus. As of 2024, Trebouxiophyceae contains 211 genera and about 925 species. Morphology Members of the Trebouxiophyceae are microscopic or macroscopic organisms which exist in a variety of forms: non-flagellate coccoid or elliptical single cells, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stichococcus
''Stichococcus'' is a genus of green algae in the family Stichococcaceae. It is a very common algal genus found in a variety of habitats, such as tree trunks, soil, snow, freshwater and marine habitats. One species, '' Stichococcus bacillaris'' is economically important as it produces fatty acids useful for biofuels. The name ''Stichococcus'' originates from the Ancient Greek στίχος (''stíkhos'', "row, line") and κόκκος (''kókkos'', "seed" or "berry"). Description ''Stichococcus'' consists of solitary cells or uniseriate filaments of few cells (2 to 4) that readily break apart. The cells are cylindrical, about three times longer than wide, straight or sometimes curved, with rounded ends often containing vacuoles. Cells are uninucleate with one thin, parietal chloroplast with or without a pyrenoid. Pyrenoids if present are located in the middle of the chloroplast but usually difficult to see. Reproduction occurs by vegetative cell division, and by the fragmentation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorella
''Chlorella'' is a genus of about thirteen species of single- celled or colonial green algae of the division Chlorophyta. The cells are spherical in shape, about 2 to 10 μm in diameter, and are without flagella. Their chloroplasts contain the green photosynthetic pigments chlorophyll-a and -b. In ideal conditions cells of ''Chlorella'' multiply rapidly, requiring only carbon dioxide, water, sunlight, and a small amount of minerals to reproduce. The name ''Chlorella'' is taken from the Greek χλώρος, ''chlōros/ khlōros'', meaning green, and the Latin diminutive suffix -''ella'', meaning small. German biochemist and cell physiologist Otto Heinrich Warburg, awarded with the Nobel Prize in Physiology or Medicine in 1931 for his research on cell respiration, also studied photosynthesis in ''Chlorella''. In 1961, Melvin Calvin of the University of California received the Nobel Prize in Chemistry for his research on the pathways of carbon dioxide assimilation in plan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyphyletic
A polyphyletic group is an assemblage that includes organisms with mixed evolutionary origin but does not include their most recent common ancestor. The term is often applied to groups that share similar features known as Homoplasy, homoplasies, which are explained as a result of convergent evolution. The arrangement of the members of a polyphyletic group is called a polyphyly .. [Source for pronunciation.] It is contrasted with monophyly and paraphyly. For example, the biological characteristic of warm-bloodedness evolved separately in the ancestors of mammals and the ancestors of birds; "warm-blooded animals" is therefore a polyphyletic grouping. Other examples of polyphyletic groups are algae, C4 photosynthesis, C4 photosynthetic plants, and Xenarthra#Evolutionary relationships, edentates. Many taxonomists aim to avoid homoplasies in grouping taxa together, with a goal to identify and eliminate groups that are found to be polyphyletic. This is often the stimulus for major re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Raphidonema (alga)
''Raphidonema'' is a genus of filamentous green alga comprising five species. It is a member of the Trebouxiophyceae. ''Raphidonema'' is widely distributed in freshwater habitats, especially snow, where it can impart a green discoloration to the snow. Description ''Raphidonema'' consists of free-floating filaments of cells, ranging from 2 to 32 cells, which may be straight or slightly curved. Interjacent cells are cylindrical, while cells at the ends taper to a point. The cell membrane is very thin and lacks a mucilaginous sheath. A single chloroplast is present in each cell, girdle- or band-shaped, lacking a pyrenoid Pyrenoids are sub-cellular phase-separated micro-compartments found in chloroplasts of many algae,Giordano, M., Beardall, J., & Raven, J. A. (2005). CO2 concentrating mechanisms in algae: mechanisms, environmental modulation, and evolution. ''An .... Reproduction occurs asexually via the vegetative division (mitosis) of cells within filaments. Taxonomy ''Raph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oogamous
Oogamy is a form of anisogamy where the gametes differ in both size and form. In oogamy the large female gamete (also known as ovum) is immotile, while the small male gamete (also known as spermatozoon) is mobile. Oogamy is a common form of anisogamy, with almost all animals and land plants being oogamous. Oogamy is found in most sexually reproducing species, including all vertebrates, land plants, and some algae. The ancestral state of sexual reproduction is believed to be isogamy, with oogamy evolving through anisogamy. Once oogamy evolves, males and females typically differ in various aspects. Internal fertilization may have originated from oogamy, although some studies suggest that oogamy in certain species may have evolved before the transition from external to internal fertilization. In streptophytes, oogamy occurred before the split from green algae. Occurrence Oogamy is found in almost all animal species that reproduce sexually. There are exceptions, such as the opili ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sexual Reproduction
Sexual reproduction is a type of reproduction that involves a complex life cycle in which a gamete ( haploid reproductive cells, such as a sperm or egg cell) with a single set of chromosomes combines with another gamete to produce a zygote that develops into an organism composed of cells with two sets of chromosomes ( diploid). This is typical in animals, though the number of chromosome sets and how that number changes in sexual reproduction varies, especially among plants, fungi, and other eukaryotes. In placental mammals, sperm cells exit the penis through the male urethra and enter the vagina during copulation, while egg cells enter the uterus through the oviduct. Other vertebrates of both sexes possess a cloaca for the release of sperm or egg cells. Sexual reproduction is the most common life cycle in multicellular eukaryotes, such as animals, fungi and plants. Sexual reproduction also occurs in some unicellular eukaryotes. Sexual reproduction does not occur in pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zoospore
A zoospore is a motile asexual spore that uses a flagellum for locomotion in aqueous or moist environments. Also called a swarm spore, these spores are created by some protists, bacteria, and fungi to propagate themselves. Certain zoospores are infectious and transmittable, such as '' Batrachochytrium dendrobatidis'', a fungal zoospore that causes high rates of mortality in amphibians. Diversity General morphology Zoospores are composed of a microtubular cytoskeleton base which extends from the base of the flagellum. The complexity and structure of this cytoskeleton is variable and is largely dependent on volume and size. One common feature of zoospores is their asymmetrical shape; a result of the ventral grove housing the flagella base. Certain zoospores progress through different phases, the first phase commonly referred to as 'the initial'. Others form cysts that vary tremendously in volume (14-4905 cubic micrometers) and shape, each with distinctive hair structures. Flag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schroederia (alga)
''Schroederia'' is a genus (biology), genus of green algae in the family Schroederiaceae. Schroederiaceae is a Monotypic taxon, monotypic taxon; ''Schroederia'' is its only genus. The genus was circumscription (taxonomy), circumscribed by Ernst Johann Lemmermann in Hedwigia vol.37 on page 311 in 1898. The genus name of ''Schroederia'' is in honour of Ludwig Julius Bruno Schröder (1867–1928), who was a German teacher, botanist (Algology and Bryology), also Hydrobiologist and Zoologist. He worked as a deputy head teacher in Breslau. Description ''Schroederia'' consists of solitary cells that are needle- or spindle-shaped. They may be straight or curved. The cells end in long spines; at one end the spine may be bifurcated. Cells contain a single parietal chloroplast and one or several pyrenoids. As the cell matures, it develops multiple parietal chloroplasts along its long axis. Cells have one cell nucleus, nucleus (uninucleate) when young but may become multinucleate. Species a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ankistrodesmus
''Ankistrodesmus'' is a genus of green algae in the family Selenastraceae. It is one of the most common types of phytoplankton in freshwater habitats around the world. The name ''Ankistrodesmus'' comes from the Greek roots ''ankistron'', meaning "cross", and ''desmos'', meaning "bond". Description ''Ankistrodesmus'' forms colonies of cells, usually found as loose bundles or tufts of cells. Sometimes the cells may twist around each other in the colony. Cells are many times longer than wide, and are variously needle-shaped, sickle-shaped, or sigmoid in outline. They contain a single chloroplast; the chloroplast usually contains a single pyrenoid, but may contain none or several pyrenoids. Life cycle Reproduction occurs asexually; sexual reproduction is unknown in ''Ankistrodesmus''. It exclusively forms autospores, and does not appear to have a flagellated stage in its life cycle. Some strains of ''Ankistrodesmus'' have been observed to undergo programmed cell death. The evolu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
