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
Determine the representation of the Nucleus In all eukaryotic cells, the nucleus represents the most prominent and conspicuous organelle of the cell, and is generally seen as a

In what ways does over-grazing lead to soil erosion? Over-grazing leads to erosion because (i) the animals delete all the vegetation, so exposing the soil to heavy rain, (ii) t

What is the evolutionary importance of the fruits for the angiosperms? The fruits have seeds and they can detach from the plant falling on the ground or can serve as food for a

What are phospholipids? Phospholipids are molecules made of glycerol bound to two long molecules of fatty acids and to one phosphate group. Thus, phospholipids are amphipathic

Define Factors related to Causing Malnutrition among CHD Patients? The various factors related to causing malnutrition among CHD patients are hypoxia (reduction in oxygen suppl

In Chemical Reactions that have a large negative /\Go' a- the total amount of both reactants and products decreases b- the products are less stable than the reactants c- t

Stratification - Aquatic ecosystems Aquatic ecosystems also exhibit marked stratification. In lake and ocean ecosystems light penetration, temperature and availability of oxyg

Name the four organisms which are currently in danger of extinction because of human activities?

Determine the Strengths of Full Battery Measures 1) Wide range of scores allow differential diagnosis in various cognitive disorders 2) More reliable, and sensitive 3) Br

How you can Repair Ventricular Aneurysm with a patch? Repair of Ventricular Aneurysm with a patch :  Originally described by Cooley, as endoaneurysmorra