Search results
Results from the WOW.Com Content Network
Hydra (/ ˈ h aɪ d r ə / HY-drə) is a genus of small freshwater hydrozoans of the phylum Cnidaria.They are native to the temperate and tropical regions. [2] [3] The genus was named by Linnaeus in 1758 after the Hydra, which was the many-headed beast of myth defeated by Heracles, as when the animal has a part severed, it will regenerate much like the mythical hydra's heads.
Hydra are typically hermaphroditic or gonochoric. Uniquely to Hydra, the medusa stage is absent and only the polyps will reproduce sexually and asexually. [2] H. viridissima will reproduce sexually when temperatures have warmed to at least 20 °C, typically this falls between May and June. Larger individuals will produce both ovaries and testes ...
Hydra oligactis. This species can reproduce in three ways: sexual reproduction, budding, and indirectly through regeneration. [11] When hydra reproduce sexually, simple testes, ovaries, or both will develop on the bodies of an individual. Sperm released into the environment by the testes enters the egg within the ovary.
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.
Females of species have the ability to reproduce asexually, without sperm from a male. The process is called parthenogenesis, from the Greek words for “virgin” and “birth.” ...
Obligate parthenogenesis is the process in which organisms exclusively reproduce through asexual means. [39] Many species have transitioned to obligate parthenogenesis over evolutionary time. Well documented transitions to obligate parthenogenesis have been found in numerous metazoan taxa, albeit through highly diverse mechanisms.
Above the genetic level, regeneration is fundamentally regulated by asexual cellular processes. [9] Regeneration is different from reproduction. For example, hydra perform regeneration but reproduce by the method of budding. The regenerative process occurs in two multi-step phases: the preparation phase and the redevelopment phase.
Some animals are capable of asexual reproduction, which often results in a genetic clone of the parent. This may take place through fragmentation; budding, such as in Hydra and other cnidarians; or parthenogenesis, where fertile eggs are produced without mating, such as in aphids. [40] [41]