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
Define the working of pH Meter? The pH of a solution, we know, measures the degree of acidity or alkalinity relative to the ionization of water sample. A pH meter is a sophisti

Explain the Relaxing Incision - Endodontic Surgery A short vertical incision placed in the marginal and attached gingival, and located at the extent of the Horizontal incision

Tracheae - Respiratory Organs Tracheal respiration is characteristic of insects. Onychophorans, diplopods, arachnids, and chilopods as well use tracheal system for respiration

Mention the role o ribosome's in peptide -bond formation .How does ATP facilitate it? a) Of springs derived by asexual reproduction are known as clones. Justify giving two R

Concerning the mixture of arterial with venous blood what is the difference between the human fetal circulation and the adult circulation? In the human fetal circulation there

CALCIUM It is the most abundant mineral of animal body. Calcium is available in all types of vegetables, grain, milk, cheese, eggs, fish and butter. By its deficiency r

Explain the Cladosporium - Fungi and Yeast? Classification Kingdom - Mycetae Division - Amastigomycota Form - Class - Deauteromycetes Form - Order - Moniliales F

Q. Iceberg phenomenon in relation to diabetes? Diabetes Mellitus cases are diagnosed by a doctor or a health worker by taking history, blood test for sugar level. But the undia

how connective tissues are like an estuary

Explain National Nutritional Anaemia Prophylaxis Programme (NNAPP)? In past, both access to and intake of iron-folate tablets have been poor in children and therefore had a lit