Transcript Comb Jellies

Comb Jellies
Phylum- Ctenophora
Phylum Ctenophora Characteristics
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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
Tentaculata
Nuda
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)
o Exchange of gas over much of surface
 Simple diffusion
Reproduction
• Hermaphrodites: produce both egg and sperm
o 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)
o Resemble miniatrue cydippid adults
o Can reproduce before fully mature
• May regenerate damaged tissue
o Up to half entire body
• Reproduce throughout entire adult life w/ sufficient
food
o Shrink during food shortage
Response to Stimuli
• Apical sense organ- holds statolith which provides balance
through sensory cilla
o 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)