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Asexual reproduction is generally used in less complex species and is quite efficient. Not having to find a mate is advantageous and allows a parent to pass down all of its traits to the next generation. However, without diversity, natural selection cannot work and if there are no mutations to make more favorable traits, asexually reproducing species may not be able to survive a changing environment. Almost all prokaryotes undergo a type of asexual reproduction called binary fission.
Binary fission is very similar to the process of mitosis in eukaryotes. However, since there is no nucleus and the DNA in a prokaryote is usually just in a single ring, it is not as complex as mitosis. Binary fission starts with a single cell that copies its DNA and then splits into two identical cells. This is a very fast and efficient way for bacteria and similar types of cells to create offspring.
However, if a DNA mutation were to occur in the process, this could change the genetics of the offspring and they would no longer be identical clones. This is one way that variation can occur even though it is undergoing asexual reproduction. In fact, bacterial resistance to antibiotics is evidence for evolution through asexual reproduction. Another type of asexual reproduction is called budding. Budding is when a new organism, or the offspring, grows off the side of the adult through a part called a bud.
The new baby will stay attached to the original adult until it reaches maturity at which point they break off and become its own independent organism. A single adult can have many buds and many offspring at the same time. Both unicellular organisms, like yeast, and multicellular organisms, like hydra, can undergo budding. Again, the offspring are clones of the parent unless some sort of mutation happens during the copying of the DNA or cell reproduction.
Some species are designed to have many viable parts that can live independently all found on one individual. These types species can undergo a type of asexual reproduction known as fragmentation. It also occurs in many plants and fungi , often with alternation between sexual and asexual reproduction. Asexual reproduction also occurs in some animals of primitive organization, such as sponges or coelenterates.
In biology, fission is the division of a unicellular organism into two or more parts and regeneration of those parts into separate individuals similar to the original. One of the most important forms of fission is binary fission. In binary fission , an organism is divided into two and gives rise to two identical descendants clones of the parent. Only prokaryotes bacteria, archaea reproduce by binary fission. In eukaryotes there is a similar mechanism of cell division, mitosis, but mitosis is a mechanism primarily of growth and development , not of reproduction.
Another type of fission is the multiple fission that occurs in many protists and unicellular algae. It is similar to binary fission but more than two daughter cells are produced; first, the cell nucleus is divided into several nuclei by mitosis and, subsequently, the cytoplasm surrounds each nucleus and separates creating multiple daughter cells. Budding is a type of asexual reproduction that is produced by asymmetric mitosis and is characterized because the new organism grows together with the parent in an area called yolk.
The broad end has 20 thin filaments, each distributed in a ring. Does not have an assigned order and only has 1 genus with 1 specie; Acidianus two-tailed virus, however Sulfolobus tengchongensis spindle-shaped viruses 1 and 2 STSV1 and STSV2 are also listed to belong to this family.
These bacteriophages are hyper thermophilic archaea viruses that target species from the genus of Acidianus. They are enveloped and have are lemon-shaped. Their genomes are circular, approximately 62kb in length and the genome has 72 open reading frames. These phages use cytoplasmic viral replication. Does not have an assigned order and only has 1 genus. They are bacilliform shaped and They have a circular double-stranded DNA molecule of 5. DNA contains 14 open reading frames.
The DNA is not integrated with host cells, and does not cause host cell lysis. Does not have an assigned order and only has 1 genus with 1 specie; Pseudoalteromonas virus PM2. Prophages which are closely related to the PM2 are of aquatic bacteria, which suggest that corticoviruses may be underestimated in their ecological importance. These bacteriophages target species of bacteria. These phages consist of a icosahedral, round, non-enveloped capsid, with a diameter of 60nm, with an internal lipid membrane found in the inner and outer protein shell.
These shells have three layers and on the surface have a pattern with bush-like spikes from twelve vertices. Does not have an assigned order and only has 1 specie in this genus; Pseudomonas phage phi6. These bacteriophages target species of phaseolicola bacteria. A distinguishing feature is their tripartite dsRNA genome, approximately 14kb in length and the protein and lipid outer layer. No other known bacteriophage has a lipid outer layer.
The most identified cystoviruses today are those which target the Pseudomonas species. These phages are enveloped, with an icosahedral and have spherical geometrics. In diameter they are approximately 85nm.
Their genomes are linear and segmented; large — 6. The genome codes contain 12 proteins. Does not have an assigned order and is a family of viruses. There are currently 9 species which are divided amongst 2 genera. These bacteriophages target species of archaea, specifically; shibatae, solfataricus, and islandicus. They are enveloped and lemon-shaped. Their diameter is 60nm with a length of nm. Their genomes are circular, approximately Does not have an assigned order and is a family of viruses which are hyperthermophilic archaeal viruses.
Currently, they have 1 genus with 2 species in this family; Pyrobaculum spherical virus and Thermoproteus tenax spherical virus 1. These bacteriophages target Crenarchaea from the genera Pyrobaculum and Thermoproteus. These phages are enveloped and spherical. Their diameter is approximately nm. Their genomes are linear dsDNA, non-segmentaed and are approximately 20kb — 30kb in length.
Does not have an assigned order and is a family of viruses, currently having 2 species divided among 2 genera. These bacteriophages target Sulfolobus newzealandicus. These phages are enveloped with a diameter that is approximately 70nm — 95nm and the length of approximately nm — nm. The genomes are circular, approximately 20kb in length. They consist of a coat, core, nucleocapsid and fibers found at pointed ends.
The surface has a bee-hive ribbed surface with protrusions that are covered with long fibers at the pointed end. Their genome is extremely heavily methylated. These bacteriophages use DNA-templated transcription. Does not have an assigned order and is a family of viruses, currently having 43 species divided among 2 genera. These bacteriophages target bacteria. These phages are nonenveloped, have a rod or filament geometrics. Their diameter is approximately 7nm and length of approximately nm.
Their genomes are circular, approximately 8kb in length and the genome codes for 4 to 10 proteins. Does not have an assigned order and is a family of viruses, currently having 4 species divided among 2 genera. These bacteriophages target bacteria, including; Enterobacteria, Caulobacter, Pseudomonas, and Acinetobacter.
These phages are icosahedral, nonenveloped and have spherical geometrics. Their diameter is approximately 26nm. Their genomes are linear and non-segmented, approximately 4kb in length and the genome codes for 4 proteins. These bacteriophages use the Positive stranded RNA virus transcription method and the lysis to exit the host cell. In some cases insects such as bees carry pollen grains with them: the grains adhere to their bodies due to small, tiny hairs that can be seen if you look at them carefully.
When they go and sit on other surfaces, the pollen grains get deposited there and that is why the process of pollination is one of those types of plants reproduction that also helps ensure that certain types of plants grown in different places in the city. Then there are those types of plants reproduction where the plants turn out to be identical to their parents and this die to the fact that they consist of the same number of chromosomes as the parents and it is due to this that the offspring is identical to the parent- it is almost as if the offspring is a clone of the parent because they appear the same, function the same and also the reproduction system is the same.
Neither of the two types of plants varies from one another because of the fact that even the chromosome count is the same. Then, there are those types of plants reproduction that are opposite to the process of mitosis and this is known as meiosis. In meiosis the process is different and the appearance of the offspring may be different from that of the parent plant.
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