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Nitellopsis Obtusa
''Nitellopsis obtusa'' is a large freshwater alga. It is also known by the common name starry stonewort.Minchin, D., Boelens, R. and Roden, C. 2017. The first record of ''Nitellopsis obtusa'' (N.A.Desvaux) J.Groves (Charophycese, Characeae) in Ireland (H9, H10) ''Irish Naturalists' Journal'' 35:(2):105 - 109 This alga grows to a length of over , is bright translucent green and has branches growing in whorls from the main axis the plants easily break up. It is easily distinguished from other charophytes by star-shaped bulbils which permit vegetative reproduction. Description ''Nitellopsis obtusa'' has long, fairly straight branches arranged in whorls, attached at nodes to the stem at an acute angle. Both stem and branches are about in diameter, and the internodal lengths of stem consist of a single cell which may be several centimetres long. Stems may be up to or even longer and form dense masses. When in active growth, the colour is light green. At the base of the main stems, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alga
Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular microalgae, such as ''Chlorella,'' ''Prototheca'' and the diatoms, to multicellular forms, such as the giant kelp, a large brown alga which may grow up to in length. Most are aquatic and autotrophic (they generate food internally) and lack many of the distinct cell and tissue types, such as stomata, xylem and phloem that are found in land plants. The largest and most complex marine algae are called seaweeds, while the most complex freshwater forms are the ''Charophyta'', a division of green algae which includes, for example, ''Spirogyra'' and stoneworts. No definition of algae is generally accepted. One definition is that algae "have chlorophyll ''a'' as their primary photosynthetic pigment and lack a sterile covering of cells around t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oogonium
An oogonium (plural oogonia) is a small diploid cell which, upon maturation, forms a primordial follicle in a female fetus or the female (haploid or diploid) gametangium of certain thallophytes. In the mammalian fetus Oogonia are formed in large numbers by mitosis early in fetal development from primordial germ cells. In humans they start to develop between weeks 4 and 8 and are present in the fetus between weeks 5 and 30. Structure Normal oogonia in human ovaries are spherical or ovoid in shape and are found amongst neighboring somatic cells and oocytes at different phases of development. Oogonia can be distinguished from neighboring somatic cells, under an electron microscope, by observing their nuclei. Oogonial nuclei contain randomly dispersed fibrillar and granular material whereas the somatic cells have a more condensed nucleus that creates a darker outline under the microscope. Oogonial nuclei also contain dense prominent nucleoli. The chromosomal material in the nucleu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oocyte
An oocyte (, ), oöcyte, or ovocyte is a female gametocyte or germ cell involved in reproduction. In other words, it is an immature ovum, or egg cell. An oocyte is produced in a female fetus in the ovary during female gametogenesis. The female germ cells produce a primordial germ cell (PGC), which then undergoes mitosis, forming oogonia. During oogenesis, the oogonia become primary oocytes. An oocyte is a form of genetic material that can be collected for cryoconservation. Formation The formation of an oocyte is called oocytogenesis, which is a part of oogenesis. Oogenesis results in the formation of both primary oocytes during fetal period, and of secondary oocytes after it as part of ovulation. Characteristics Cytoplasm Oocytes are rich in cytoplasm, which contains yolk granules to nourish the cell early in development. Nucleus During the primary oocyte stage of oogenesis, the nucleus is called a germinal vesicle. The only normal human type of secondary oocyte has t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chara (alga)
''Chara'' is a genus of charophyte green algae in the family Characeae. They are multicellular and superficially resemble land plants because of stem-like and leaf-like structures. They are found in freshwater, particularly in limestone areas throughout the northern temperate zone, where they grow submerged, attached to the muddy bottom. They prefer less oxygenated and hard water and are not found in waters where mosquito larvae are present. They are covered with calcium carbonate deposits and are commonly known as stoneworts. Cyanobacteria have been found growing as epiphytes on the surfaces of ''Chara'', where they may be involved in fixing nitrogen, which is important to plant nutrition. Structure The branching system of ''Chara'' species is complex with branches derived from apical cells which cut off segments at the base to form nodal and internodal cells alternately.Round, F.E. 1965.''The Biology of the algae.'' Ernest Arnold. The main axes bear whorls of branches in a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitella
''Nitella'' is a genus of charophyte green algae in the family Characeae. Species The species in the genus include: *'' Nitella abyssinica'' A. Braun * '' Nitella acuminata'' A. Braun ex Wallman *'' Nitella aemula'' A. Braun * '' Nitella annandalei'' B.P. Pal * '' Nitella australiensis'' (F.M. Bailey) J.C. van Raam * '' Nitella axillaris'' A. Braun * '' Nitella axilliformis'' Imahori * '' Nitella capillaris'' (A.J.Krocker) J.Groves & G.R.Bullock-Webster * '' Nitella comptonii'' J. Groves * '' Nitella cristata'' A. Braun * '' Nitella diffusa'' A. Braun * '' Nitella flexilis'' (Linnaeus) C. Agardh * ''Nitella furcata'' (Roxburgh ex Bruzelius) C. Agardh * '' Nitella gelatinifera'' R.D. Wood * '' Nitella gelatinosa'' A. Braun * '' Nitella gloeostachys'' A. Braun * ''Nitella gracilens'' Morioka * ''Nitella gracilis'' (J.E.Smith) C.Agardh * ''Nitella gracillima'' T.F. Allen * ''Nitella haagenii'' J.C. van Raam * ''Nitella heterophylla'' A. Braun * ''Nitella hookeri'' A. Braun * ''N ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Detritus
In biology, detritus () is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts communities of microorganisms that colonize and decompose (i.e. remineralize) it. In terrestrial ecosystems it is present as leaf litter and other organic matter that is intermixed with soil, which is denominated " soil organic matter". The detritus of aquatic ecosystems is organic material that is suspended in the water and accumulates in depositions on the floor of the body of water; when this floor is a seabed, such a deposition is denominated "marine snow". Theory The corpses of dead plants or animals, material derived from animal tissues (e.g. molted skin), and fecal matter gradually lose their form due to physical processes and the action of decomposers, including grazers, bacteria, and fungi. Decomposition, the process by which or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia and it is located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. Comprising the westernmost peninsulas of Eurasia, it shares the continental landmass of Afro-Eurasia with both Africa and Asia. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south and Asia to the east. Europe is commonly considered to be Boundaries between the continents of Earth#Asia and Europe, separated from Asia by the drainage divide, watershed of the Ural Mountains, the Ural (river), Ural River, the Caspian Sea, the Greater Caucasus, the Black Sea and the waterways of the Turkish Straits. "Europe" (pp. 68–69); "Asia" (pp. 90–91): "A commonly accepted division between Asia and E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asia
Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area of , about 30% of Earth's total land area and 8.7% of Earth's total surface area. The continent, which has long been home to the majority of the human population, was the site of many of the first civilizations. Its 4.7 billion people constitute roughly 60% of the world's population. In general terms, Asia is bounded on the east by the Pacific Ocean, on the south by the Indian Ocean, and on the north by the Arctic Ocean. The border of Asia with Europe is a historical and cultural construct, as there is no clear physical and geographical separation between them. It is somewhat arbitrary and has moved since its first conception in classical antiquity. The division of Eurasia into two continents reflects East–West cultural, linguistic, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cosmeston Lakes Country Park
Cosmeston Lakes Country Park is a public country park in Wales, owned and managed by Vale of Glamorgan Council. It is situated between Penarth and Sully, Vale of Glamorgan, 7.3 miles (11.7 kilometres) from Cardiff. On 1 May 2013 the country park was designated a Local Nature Reserve. Parts are Sites of Special Scientific Interest. The park, visitor centre, and cafe are open all year round. General The main feature at this country park are the two large lakes divided by a bridge on the main footpath 'mile road'. The country park has a variety of habitats covering over 100 hectares of land and water, with some areas designated a Site of Special Scientific Interest, protecting the rare and diverse plant and animal species.Cosmeston Lakes Country ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vale Of Glamorgan
The Vale of Glamorgan ( cy, Bro Morgannwg ), often referred to as The Vale, is a county borough in the south-east of Wales. It borders Bridgend County Borough to the west, Cardiff to the east, Rhondda Cynon Taf to the north, and the Bristol Channel to the south. With an economy based largely on agriculture and chemicals, it is the southernmost unitary authority in Wales. Attractions include Barry Island Pleasure Park, the Barry Tourist Railway, Medieval wall paintings in St Cadoc's Church, Llancarfan, Porthkerry Park, St Donat's Castle, Cosmeston Lakes Country Park and Cosmeston Medieval Village. The largest town is Barry. Other towns include Penarth, Llantwit Major, and Cowbridge. There are many villages in the county borough. History The area is the southernmost part of the county of Glamorgan. Between the 11th century and 1536 the area was part of the Lordship of Glamorgan. In medieval times, the village of Cosmeston, near what is today Penarth in the south east of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Invasive Species
An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species adversely affect habitats and bioregions, causing ecological, environmental, and/or economic damage. The term can also be used for native species that become harmful to their native environment after human alterations to its food webfor example the purple sea urchin (''Strongylocentrotus purpuratus'') which has decimated kelp forests along the northern California coast due to overharvesting of its natural predator, the California sea otter (''Enhydra lutris''). Since the 20th century, invasive species have become a serious economic, social, and environmental threat. Invasion of long-established ecosystems by organisms is a natural phenomenon, but human-facilitated introductions have greatly increased the rate, scale, and geographic range of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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