Class polychaeta - classification of coelom, Biology

Class Polychaeta - Classification of Coelom

There are mainly marine forms with distinct head, having eyes and tentacles, segments have lateral projections of the body wall termed as parapodia which carry bundles of setae. These animals do not have clitellum. Sexes are separating (dioecious). They have no different or permanent sex organs, but their gonads consist of masses of developing gametes arising as swellings of Peritoneum. Eggs generally develop into trochophore larva. Many forms reproduce asexually by budding. ? Most of the polychaetes are 5-10 cm long. They live below rocks and in crevices, or burrow in mud. Some build tubes. Other is pelagic. These animals are generally divided into

(1) Errant forms on the one hand that are freely moving, pelagic, active burrowers, crawlers and the tube worms which leave their tubes for several purposes. On the other hand

(2) The sedentary forms do not leave their tubes or burrows but may generally expose just only their heads outside.

Errant polychaete structure may be considered classic of a generalised polychaete. The prostomium is very well developed, with several sense organs such as eyes, antennae, palps and the nuchal organs. Prostomium is dorsal and preoral projecting over the mouth. The peristomium that is the first segment carries the mouth. The predatory forms have jaws in the mouth. The peristomium is often fused along with one or more subsequent segments forming the head. These segments as well usually carry sensory structures, but their parapodium as well bears bundles of chitinous setae in the setal sacs. Nereis is a typical example. A cross section of its body by one of its middle segments shows well its internal organisation.

Posted Date: 2/2/2013 12:31:06 AM | Location : United States







Related Discussions:- Class polychaeta - classification of coelom, Assignment Help, Ask Question on Class polychaeta - classification of coelom, Get Answer, Expert's Help, Class polychaeta - classification of coelom Discussions

Write discussion on Class polychaeta - classification of coelom
Your posts are moderated
Related Questions
Explain the Prevalence of iron deficiency anaemia? We can find out about the prevalence of anaemia if we know what percentage of population is suffering from anaemia. The WHO h

T ertiary Structure (3 o S tructure) Highly folded protein. Globular in structure. Tertiary structure is stabilised by five types of bonds : (i )      P

Carbon Based Materials These include Pyrolytic carbon, polycrystalline (Vitreous Carbon), and carbon/silicon interstitial combination. Vitreous Carbon -Solid or porous vitre

Explain single pan balance and Electronic Digital Balance? Single Pan Balance: This is a very sensitive balance used for weighing quantities less than 10 grams. It accurately w

Describe three ways that RNA differs from DNA. RNA is single stranded; DNA is double stranded all of the codons from the deletion point to the end of the transcript would be s

how i prepare my best assignment on DNA Polymerase 1 2 and 3

How many grams of sodium dodecyl sulfate (mw = 288.37) would you dissolve in 80mLs of water to make a 20% solution of SDS?

Q. Complications Causes by gastro oesophageal reflux disease? Apart from the symptoms, which you have just read above, there are a few extra oesophageal manifestations of GERD.

Define Requirements of Chromium? There is no Recommended Dietary Allowance (RDA) for chromium but adequate intakes that can be used as a goal for individual intakes has been pr

Why do some physicians advise patients with a bladder infection to drink a lot of cranberry juice? Answer Cranberry juice contains chemicals that kill viruses and bacteria. The inc