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Hydrodictyon
The water net (genus ''Hydrodictyon'') is a taxon of freshwater green algae in the family Hydrodictyaceae. ''Hydrodictyon'' does well in clean, eutrophic water, and has become a nuisance in New Zealand, where it has been recently introduced. The name ''water net'' comes from the (usually pentagonal or hexagonal) mesh structure of their colonies, which can extend several decimeters. Reproduction in hydrodictyon Algae in the genus can reproduce asexually or sexually. Asexual reproduction takes place by biflagellated (having two flagella) zoospores formed by the thousands inside a cell. However, the zoospores hardly move, as they are packed very densely. The zoospores form a cell wall, become cylindrical in shape, and arrange themselves in a hexagonal pattern, much like the mature tissue. The mother cell disintegrates, releasing the microscopic daughter net. During sexual reproduction, which takes place by iso-gametes (gametes of the same size) even smaller than the zoospores, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrodictyon Africanum
The water net (genus ''Hydrodictyon'') is a taxon of freshwater green algae in the family Hydrodictyaceae. ''Hydrodictyon'' does well in clean, eutrophic water, and has become a nuisance in New Zealand, where it has been recently introduced. The name ''water net'' comes from the (usually pentagonal or hexagonal) mesh structure of their colonies, which can extend several decimeters. Reproduction in hydrodictyon Algae in the genus can reproduce asexually or sexually. Asexual reproduction takes place by biflagellated (having two flagella) zoospores formed by the thousands inside a cell. However, the zoospores hardly move, as they are packed very densely. The zoospores form a cell wall, become cylindrical in shape, and arrange themselves in a hexagonal pattern, much like the mature tissue. The mother cell disintegrates, releasing the microscopic daughter net. During sexual reproduction, which takes place by iso-gametes (gametes of the same size) even smaller than the zoospores, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrodictyon Patenaeforme
The water net (genus ''Hydrodictyon'') is a taxon of freshwater green algae in the family Hydrodictyaceae. ''Hydrodictyon'' does well in clean, eutrophic water, and has become a nuisance in New Zealand, where it has been recently introduced. The name ''water net'' comes from the (usually pentagonal or hexagonal) mesh structure of their colonies, which can extend several decimeters. Reproduction in hydrodictyon Algae in the genus can reproduce asexually or sexually. Asexual reproduction takes place by biflagellated (having two flagella) zoospores formed by the thousands inside a cell. However, the zoospores hardly move, as they are packed very densely. The zoospores form a cell wall, become cylindrical in shape, and arrange themselves in a hexagonal pattern, much like the mature tissue. The mother cell disintegrates, releasing the microscopic daughter net. During sexual reproduction, which takes place by iso-gametes (gametes of the same size) even smaller than the zoospores, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrodictyon Reticulatum
The water net (genus ''Hydrodictyon'') is a taxon of freshwater green algae in the family Hydrodictyaceae. ''Hydrodictyon'' does well in clean, eutrophic water, and has become a nuisance in New Zealand, where it has been recently introduced. The name ''water net'' comes from the (usually pentagonal or hexagonal) mesh structure of their colonies, which can extend several decimeters. Reproduction in hydrodictyon Algae in the genus can reproduce asexually or sexually. Asexual reproduction takes place by biflagellated (having two flagella) zoospores formed by the thousands inside a cell. However, the zoospores hardly move, as they are packed very densely. The zoospores form a cell wall, become cylindrical in shape, and arrange themselves in a hexagonal pattern, much like the mature tissue. The mother cell disintegrates, releasing the microscopic daughter net. During sexual reproduction, which takes place by iso-gametes (gametes of the same size) even smaller than the zoospores, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrodictyon Indicum
The water net (genus ''Hydrodictyon'') is a taxon of freshwater green algae in the family Hydrodictyaceae. ''Hydrodictyon'' does well in clean, eutrophic water, and has become a nuisance in New Zealand, where it has been recently introduced. The name ''water net'' comes from the (usually pentagonal or hexagonal) mesh structure of their colonies, which can extend several decimeters. Reproduction in hydrodictyon Algae in the genus can reproduce asexually or sexually. Asexual reproduction takes place by biflagellated (having two flagella) zoospores formed by the thousands inside a cell. However, the zoospores hardly move, as they are packed very densely. The zoospores form a cell wall, become cylindrical in shape, and arrange themselves in a hexagonal pattern, much like the mature tissue. The mother cell disintegrates, releasing the microscopic daughter net. During sexual reproduction, which takes place by iso-gametes (gametes of the same size) even smaller than the zoospores, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrodictyaceae
Hydrodictyaceae is a family of green algae in the order Sphaeropleales. Genera * '' Euastropsis'' * '' Helierella'' * '' Hydrodictyon'' * '' Lacunastrum'' * '' Monactinus'' * '' Parapediastrum'' * ''Pediastrum ''Pediastrum'' is a genus of green algae, in the family Hydrodictyaceae. It is a photoautotrophic, nonmotile coenobial (fixed number of cells) green algae that inhabits freshwater environments. Morphology ''Pediastrum'' is a genus usually lo ...'' * '' Pseudopediastrum'' * '' Sorastrum'' * '' Sphaerastrum'' * '' Stauridium'' * '' Tetraedroides'' * '' Tetraedron'' * '' Tetrapedia'' References Chlorophyceae families Sphaeropleales {{Chlorophyceae-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reproduction
Reproduction (or procreation or breeding) is the biological process by which new individual organisms – "offspring" – are produced from their "parent" or parents. Reproduction is a fundamental feature of all known life; each individual organism exists as the result of reproduction. There are two forms of reproduction: asexual and sexual. In asexual reproduction, an organism can reproduce without the involvement of another organism. Asexual reproduction is not limited to single-celled organisms. The cloning of an organism is a form of asexual reproduction. By asexual reproduction, an organism creates a genetically similar or identical copy of itself. The evolution of sexual reproduction is a major puzzle for biologists. The two-fold cost of sexual reproduction is that only 50% of organisms reproduce and organisms only pass on 50% of their genes. John Maynard Smith ''The Evolution of Sex'' 1978. Sexual reproduction typically requires the sexual interaction of two speci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zygote
A zygote (, ) is a eukaryotic cell formed by a fertilization event between two gametes. The zygote's genome is a combination of the DNA in each gamete, and contains all of the genetic information of a new individual organism. In multicellular organisms, the zygote is the earliest developmental stage. In humans and most other anisogamous organisms, a zygote is formed when an egg cell and sperm cell come together to create a new unique organism. In single-celled organisms, the zygote can divide asexually by mitosis to produce identical offspring. German zoologists Oscar and Richard Hertwig made some of the first discoveries on animal zygote formation in the late 19th century. Humans In human fertilization, a released ovum (a haploid secondary oocyte with replicate chromosome copies) and a haploid sperm cell ( male gamete) combine to form a single diploid cell called the zygote. Once the single sperm fuses with the oocyte, the latter completes the division of the se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gamete
A gamete (; , ultimately ) is a haploid cell that fuses with another haploid cell during fertilization in organisms that reproduce sexually. Gametes are an organism's reproductive cells, also referred to as sex cells. In species that produce two morphologically distinct types of gametes, and in which each individual produces only one type, a female is any individual that produces the larger type of gamete—called an ovum— and a male produces the smaller type—called a sperm. Sperm cells or spermatozoa are small and motile due to the flagellum, a tail-shaped structure that allows the cell to propel and move. In contrast, each egg cell or ovum is relatively large and non-motile. In short a gamete is an egg cell (female gamete) or a sperm (male gamete). In animals, ova mature in the ovaries of females and sperm develop in the testes of males. During fertilization, a spermatozoon and ovum unite to form a new diploid organism. Gametes carry half the genetic information o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microscopic
The microscopic scale () is the scale of objects and events smaller than those that can easily be seen by the naked eye, requiring a lens or microscope to see them clearly. In physics, the microscopic scale is sometimes regarded as the scale between the macroscopic scale and the quantum scale. Microscopic units and measurements are used to classify and describe very small objects. One common microscopic length scale unit is the micrometre (also called a ''micron'') (symbol: μm), which is one millionth of a metre. History Whilst compound microscopes were first developed in the 1590s, the significance of the microscopic scale was only truly established in the 1600s when Marcello Malphigi and Antonie van Leeuwenhoek microscopically observed frog lungs and microorganisms. As microbiology was established, the significance of making scientific observations at a microscopic level increased. Published in 1665, Robert Hooke’s book Micrographia details his microscopic observat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zoospore
A zoospore is a motile asexual spore that uses a flagellum for locomotion. Also called a swarm spore, these spores are created by some protists, bacteria, and fungi to propagate themselves. Diversity Flagella types Zoospores may possess one or more distinct types of flagella - tinsel or "decorated", and whiplash, in various combinations. *Tinsellated (straminipilous) flagella have lateral filaments known as mastigonemes perpendicular to their main axis, which allow for more surface area, and disturbance of the medium, giving them the property of a rudder, that is, used for steering. *Whiplash flagella are straight, to power the zoospore through its medium. Also, the "default" zoospore only has the propelling, whiplash flagella. Both tinsel and whiplash flagella beat in a sinusoidal wave pattern, but when both are present, the tinsel beats in the opposite direction of the whiplash, to give two axes of control of motility. Morphological types In eukaryotes, the four main ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flagella
A flagellum (; ) is a hairlike appendage that protrudes from certain plant and animal sperm cells, and from a wide range of microorganisms to provide motility. Many protists with flagella are termed as flagellates. A microorganism may have from one to many flagella. A gram-negative bacterium '' Helicobacter pylori'' for example uses its multiple flagella to propel itself through the mucus lining to reach the stomach epithelium, where it may cause a gastric ulcer to develop. In some bacteria the flagellum can also function as a sensory organelle, being sensitive to wetness outside the cell. Across the three domains of Bacteria, Archaea, and Eukaryota the flagellum has a different structure, protein composition, and mechanism of propulsion but shares the same function of providing motility. The Latin word means " whip" to describe its lash-like swimming motion. The flagellum in archaea is called the archaellum to note its difference from the bacterial flagellum. Eukaryotic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New Zealand
New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island country by area, covering . New Zealand is about east of Australia across the Tasman Sea and south of the islands of New Caledonia, Fiji, and Tonga. The country's varied topography and sharp mountain peaks, including the Southern Alps, owe much to tectonic uplift and volcanic eruptions. New Zealand's capital city is Wellington, and its most populous city is Auckland. The islands of New Zealand were the last large habitable land to be settled by humans. Between about 1280 and 1350, Polynesians began to settle in the islands and then developed a distinctive Māori culture. In 1642, the Dutch explorer Abel Tasman became the first European to sight and record New Zealand. In 1840, representatives of the United Kingdom and Māori chiefs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
