Fearless

Jellyfish atomic number 18 usually either male or female (occasionally hermaphroditic specimens are found). In most cases, both(prenominal) release spermatozoan and eggs into the surrounding water, where the (unprotected) eggs are fertilized and mature into new organisms. In a few species, the sperm swim into the females lip fertilizing the eggs within the females body where they persevere for the early stages of development. In moon jellies, the eggs lodge in pits on the oral arms, which form a temporary drove chamber for the developing planula larvae.

Most jellyfish undergo two distinct life history stages (body forms) during their life cycle. The first is the polypusoid stage. afterwards fertilization and initial ontogenesis, a larval form, called the planula, develops. The planula is a polished larva covered with cilia. It settles onto a firm surface and develops into a polyp. The polyp is generally a small stalk with a mouth surrounded by upward-facing tentacles like miniatures of the closely related actinozoan polyps (sea anemones and corals), also of the phylum Cnidaria. This polyp may be sessile, living on the bottom or on similar substrata such as floats or boat-bottoms, or it may be free-floating or addicted to tiny bits of free-living plankton[20] or rarely, fish[21] or other invertebrates.



Polyps may be solitary or colonial, and some bud asexually by various means, making more polyps. Most are very small, measured in millimeters.

After a growth interval, the polyp begins reproducing asexually by budding and, in the Scyphozoa, is called a segmenting polyp, or a scyphistoma. New scyphistomae may be produced by budding or new, immature jellies called ephyrae may be formed. A few jellyfish species can produce new medusae by budding directly from the medusan stage. Budding sites vary by species; from the tentacle bulbs, the manubrium (above the mouth), or the gonads of hydromedusae. A few of species of hydromedusae reproduce by fission (splitting in half).[20]

In the second stage, the tiny...If you want to get a full essay, order it on our website: Ordercustompaper.com



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