Introduction to Ctenophores

?

Introduction to Ctenophores

  • CTENOPHORA: a small phylum of aquatic invertebrates that comprises the comb jellies
  • some live in brackish waters but the group is otherwise confined to marine habitats
  • carnivorous, except for one parasitic species 
1 of 4

Structure of Ctenophores

  • most are small but at least one species can grow to lengths of more than 1 metre
  • most are colourless, but some species can be pink or violet
  • have a statocyst at the aboral end of the body, and a mouth at the oral end
  • eight comb rows extend orally from the statocyst and serve as organs of locomotion 
  • more primitive forms have a pair of long, retractable tentacles that capture food
    • the tentacles have adhesive cells called colloblasts which are unique to ctenophores
  • have a complex series of canals that make up the digestive tract, which also serves circulatory functions and is therefore known as the gastrovascular cavity
2 of 4

Taxonomy and Diversity of Ctenophores

  • roughly 90 known species in two classes, with most being either spherical or oval
  • TENTECULATA: class of ctenophores that have a pair of long, feathery, contractile tentacles, which can be retracted into specialised ciliated sheaths
  • NUDA: class of ctenophores that do not have tentacles
3 of 4

Reproduction, Development, and Lifecycle of Ctenop

  • adults of most species can regenerate tissues that are damaged or removed
  • hermaphroditic, with eggs and sperm produced in separate gonads along the meridional canals that house the comb rows
  • in some groups the larva closely resemble the adult, but in most there are cydippid larva
  • no metamorphosis
  • in at least some species, juvenile ctenophores are capable of producing small quantities of eggs and sperm while they are below adult size
4 of 4

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Invertebrate Zoology resources »