Ticket #5849 (new)

Opened 10 days ago

Leave your feedback and you could WIN!

Reported by: "Thank You Home Depot" <HomeDepotShopperFeedback@…> Owned by:
Priority: normal Milestone: 2.11
Component: none Version: 3.8.0
Severity: medium Keywords:
Cc: Language:
Patch status: Platform:

Description

Leave your feedback and you could WIN!

http://manifestationz.us/qiqszbw6omYhBBs8e1px875YzvYrNyrnykGBSoaHyZKYsjZ_uQ

http://manifestationz.us/96gMABJhIBGH_pVXGQuUuW1sa48UxpXd38WKV7bycT6N37zAfA

rinoids are dioecious, with individuals being either male or female. In most species, the gonads are located in the pinnules but in a few, they are located in the arms. Not all the pinnules are reproductive, just those closest to the crown. The gametes are produced in genital canals enclosed in genital coeloms. The pinnules eventually rupture to release the sperm and eggs into the surrounding sea water. In certain genera, such as Antedon, the fertilised eggs are cemented to the arms with secretions from epidermal glands; in others, especially cold water species from Antarctica, the eggs are brooded in specialised sacs on the arms or pinnules.

The fertilised eggs hatch to release free-swimming vitellaria larvae. The bilaterally symmetrical larva is barrel-shaped with rings of cilia running round the body, and a tuft of sensory hairs at the upper pole. While both feeding (planktotrophic) and non-feeding (lecithotrophic) larvae exist among the four other extant echinoderm classes, all present day crinoids appear to be descendants from a surviving clade that went through a bottleneck after the Permian extinction, at that time losing the feeding larval stage. The larva's free-swimming period lasts for only a few days before it settles on the bottom and attaches itself to the underlying surface using an adhesive gland on its underside. The larva then undergoes an extended period of metamorphoses into a stalked juvenile, becoming radially symmetric in the process. Even the free-swimming feather stars go through this stage, with the adult eventually breaking away from the stalk.

Locomotion

A stalked crinoid (white) and a comatulid (red) in deep sea, showing the differences between these two sister groups
Most modern crinoids, i.e., the feather stars, are free-moving and lack a stem as adults. Examples of fossil crinoids that have been interpreted as free-swimming include Marsupitsa, Saccocoma and Uintacrinus. In general, crinoids move to new locations by crawling, using the cirri as legs. Such a movement may be induced in relation to a change in current direction, the need to climb to an elevated perch to feed, or because of an ago

untitled-part.html Download

Attachments

untitled-part.html Download (3.9 KB) - added by HomeDepotShopperFeedback@… 10 days ago.
Added by email2trac

Change History

Changed 10 days ago by HomeDepotShopperFeedback@…

Changed 10 days ago by HomeDepotShopperFeedback@…

This message has 1 attachment(s)

Changed 10 days ago by HomeDepotShopperFeedback@…

Added by email2trac

Note: See TracTickets for help on using tickets.