BIO325H5 Lecture Notes - Lecture 8: Standard Gravity, Aurelia Aurita, Froude Number
Document Summary
Perhaps not, but they are very efficient: contribution of the stopping vortex is part of the reason jellyfish are so efficient. Sea squirts are sessile barrel-shaped creatures, often living in clusters. Through an incurrent siphon, see os (a) Beating cilia draw seawater into a large slitted pharynx. Musuc sliding on the pharynx walls, filters out. Microfoods" such as diatoms, concentrating them in the gut. The current exits the pharynx via gill slits into a surrounding cavity called an atrium, leading to excurrent siphon (ats) Some species of tunicate, called salps, have modified this filter-feeding system for jetting. A propulsive jet for locomotion is created by rhythmic compression of muscle bands encircling the barrel-shaped body. Seawater enters pharynx via the [closable incurrent siphon] oral lips close and circular muscle bands contract, decreasing the volume of the jet chamber [atrium] so that seawater is accelerated out of the [now] posterior [excurrent] siphon [antagonists?]
