Sessile

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LIFESTYLE
Benthos | Nekton | Plankton | Semi-aquatic | Sessile | Terrestrial | Vagile


Sessile
Some Devonian high tiered sessile organisms, including the crinoid Dolatocrinus and the giant rugose coral Siphonophrentis.
Some Devonian high tiered sessile organisms, including the crinoid Dolatocrinus and the giant rugose coral Siphonophrentis.
Some modern-day sessile organisms. In the foreground is the Elephant Ear sponge, Agelas clathrodes (Porifera, Demospongiae, Ceractinomorpha, Agelasida, Agelasidae). In the middle background is a deep water sea fan, Iciligorgia schrammi (Anthothelidae), and at the right the giant slit-pore sea rod, Plexaurella nutans (Plexauridae), both soft corals (Cnidaria, Anthozoa, Alcyonaria, Alcyonacea). Florida Keys National Maritime Sanctuary.
Some modern-day sessile organisms. In the foreground is the Elephant Ear sponge, Agelas clathrodes (Porifera, Demospongiae, Ceractinomorpha, Agelasida, Agelasidae). In the middle background is a deep water sea fan, Iciligorgia schrammi (Anthothelidae), and at the right the giant slit-pore sea rod, Plexaurella nutans (Plexauridae), both soft corals (Cnidaria, Anthozoa, Alcyonaria, Alcyonacea). Florida Keys National Maritime Sanctuary.
Sessile organisms are attached to the substrate, for example Porifera (sponges), Anthozoa (corals), Bryozoa, Brachiopoda, some Bivalves, Cirripedia (barnacles), Crinozoa, and Urochordata (sea squirts). The term is usually applied in reference to benthic animals, since pelagic organisms by their very nature would be able to move about, whilst plants and fungi are fixed in place anyway.

Sessile organisms typically have a mobile (called vagile) or motile larval phase in their development, which becomes attached and sessile at maturity. However the pattern is reversed in Scyphozoa (jellyfish) which begin life as sessile polyps (when the planula settles down).

Some sponges and sessile Cnidaria are capable of asexual reproduction through budding. Sessile organisms may be solitary or grow together in clumps. Competition for light and food resources may cause sessile organisms to grow in tiers (see benthic tiering).

The garden eels, genus Heteroconger, have the unique distinction of being the world's only sessile vertebrates, as they never leave their burrows as adults.

In botany, sessile means "without a stalk", as in flowers or leaves that grow directly from the stem, such as the flowers of the cacao tree, Theobroma cacao, emerge directly from the tree trunk.

[edit] Credits

MAK061106 (with some material from wikipedia)

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