Life cycle with picture hereLife cycle
The eggs develop in gonads of female medusae, which are located in the walls of the manubrium (stomach). Mature eggs are presumably spawned and fertilized in the sea by sperm produced and released by male medusae, as is the case for most hydromedusae, although the related species Turritopsis rubra seems to retain fertilized eggs until the planula stage[9]. Fertilized eggs develop into planula larvae, which settle onto the sea floor (or even the rich marine communities that live on floating docks), and develop into polyp colonies (hydroids). The hydroids bud new jellyfishes, which are released at about 1 mm in size and then grow and feed in the plankton, becoming sexually mature after a few weeks (the exact duration depends on the ocean temperature; at 20 °C (68 °F) it is 25 to 30 days and at 22 °C (72 °F) it is 18 to 22 days).[3]
[edit] Biological immortality
Most jellyfish species have a relatively fixed life span, which varies by species from hours to many months (long-lived mature jellyfish spawn every day or night [the time is also rather fixed and species-specific][12]). The medusa of Turritopsis nutricula is the only form known to have developed the ability to return to a polyp state, by a specific transformation process that requires the presence of certain cell types (tissue from both the jellyfish bell surface and the circulatory canal system). Careful laboratory experiments have revealed that all stages of the medusae, from newly released to fully mature individuals, can transform back into polyps.[3] The transforming medusa is characterized first by deterioration of the bell and tentacles, with subsequent growth of a perisarc sheet (see hydroid) and stolons, and finally feeding polyps. Polyps further multiply by growing additional stolons, branches and then polyps, to form colonial hydroids. This ability to reverse the life cycle (in response to adverse conditions) is probably unique in the animal kingdom, and allows the jellyfish to bypass death, rendering Turritopsis nutricula potentially biologically immortal. Studies in the laboratory showed that 100% of specimens could revert to the polyp stage, but so far the process has not been observed in nature, in part because the process is quite rapid and field observations at the right moment in time are unlikely.[3] In spite of this remarkable ability, most Turritopsis medusae are likely to fall victim to the general hazards of life as plankton, including being eaten by other animals, or succumbing to disease.
OK, this is not breaking news perse, but I just found this out and I found this pretty damn cool to share.
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- PeZook
