Comb JelliesPhylum- Ctenophora Mikaela Dewalt, Carly Muller, James Dodd-o
Phylum Ctenophora Characteristics • all are marine • fragile • luminescent • size range: from approx. the size of a pea to approx. the size of a tomato • outer surface bears 8 rows of cilia resembling a comb, hence the name • biradially symmetrical • have similar characteristics of the Cnidarians • largest of all animals to use cilia for movement
Ctenophora Classes • Tentaculata: class of comb jellies that contain two tentacles which consist of sticky end tips that help the jelly capture prey • Nuda: class of comb jellies that do not contain tentacles throughout any stage of their life
Anatomy/Body Form - The body of the ctenophora consists of a thick mesoglea which is pressed between two layers of epithelia. - The outer layer of the skin consists of: sensory cells, cells that secrete mucus which protects the comb jellies body, and interstitial cells which are able to transform into other types of cells. -The largest and most complex sensor of the comb jelly is the apical sence organ, which is a balance sensor. -Comb Jellies have eight large rows of cilia that are shaped like combs run from the mouth to the aboral pore on the jelly for locomotion. -Neither protostomes or deuterostomes
Anatomy/ Body Form continued -The internal cavity of the comb jelly consists of a mouth, a pharynx, a wide area which acts as a stomach, and a system of internal canals. -These canals branch through the mesoglea towards the most active parts of the jelly: the mouth, the pharynx, the roots of the tentacles, along the underside of each of the eight rows of cilia, and the four branches around the sensory complex towards the far end of the jellies mouth.
Feeding Practices -After the prey is swallowed, it is liquefied in the pharynx by enzymes and muscular contractions of the pharynx. After the prey is liquified, it is pushed throughout the canal system by cilia and is finally digested by nutritive cells. -Tentaculata will first trap their food in their tentacles rather then stinging them before taking the prey into their mouths. -Nuda have to chase their prey or ambush them as they have no other means of capturing their prey due to the lack of tentacles and they eat their prey whole.
Gas Exchange • Large surface area realitive to carbon content (low) • Exchange of gas over much of surface • Simple diffusion
Reproduction • Hermaphrodites: produce both egg and sperm • Self-fertilization • Usually outside the body, released directly into water through mouth • Free-floating fertilized egg • Platyctenids=internal fertilization • No distinct larval form (some planktonic young) • Resemble miniatrue cydippid adults • Can reproduce before fully mature • May regenerate damaged tissue • Up to half entire body • Reproduce throughout entire adult life w/ sufficient food • Shrink during food shortage
Response to Stimuli • Apical sense organ- holds statolith which provides balance through sensory cilla • Cilla stimulated by touch will adjust beating patterns accordingly • Dragging tentacles allow to feel prey on ocean floor • Location depends on penetration ability of light (greater penetration=ability to live in deeper water)