Ctenophores - Description - Common Features - Locomotion

Locomotion

The outer surface bears usually eight comb rows, which are used for swimming. The rows are oriented to run from near the mouth (the "oral pole") to the opposite end (the "aboral pole"), and are spaced more or less evenly around the body, although spacing patterns vary by species and in most species the comb rows extend only part of the distance from the aboral pole towards the mouth. The "combs" (also called "ctenes" or "comb plates") run across each row, and each consists of thousands of unusually long cilia, up to 2 millimeters (0.079 in). These normally beat so that the propulsion stroke is away from the mouth, although they can also reverse direction. Hence ctenophores usually swim in the direction in which the mouth is pointing, unlike jellyfish. When trying to escape predators, one species can accelerate to six times its normal speed; some other species reverse direction as part of their escape behavior, by reversing the power stroke of the comb plate cilia.

It is uncertain how ctenophores control their buoyancy, but experiments have shown that some species rely on osmotic pressure to adapt to water of different densities. Their body fluids are normally as concentrated as seawater. If they enter less dense brackish water, the ciliary rosettes in the body cavity may pump this into the mesoglea to increase its bulk and decrease its density, to avoid sinking. Conversely if they move from brackish to full-strength seawater, the rosettes may pump water out of the mesoglea to reduce its volume and increase its density.

Read more about this topic:  Ctenophores, Description, Common Features

Other articles related to "locomotion":

Scotoplanes - Locomotion
... that have taken on a leg-like appearance, and are the only instance of legged locomotion amongst the holothurians, using water cavities within the skin (rather ...
Locomotion - Fiction and Entertainment
... Chris Sawyer's Locomotion, a 2004 computer game by Chris Sawyer Loco-Motion (arcade game), a 1982 arcade game by Konami "The Loco-Motion", a 1960s hit song, originally performed by ...
Aquatic Locomotion - See Also
... Swimming portal Fish fins Role of skin in locomotion Tradeoffs for locomotion in air and water Undulatory locomotion ...
Arboreal Locomotion
... Arboreal locomotion is the locomotion of animals in trees ... In every habitat in which trees are present, animals have evolved to move in them ...