Class polychaeta - classification of coelom, Biology

Assignment Help:

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.


Related Discussions:- Class polychaeta - classification of coelom

Explain what is enzymes, Explain what is Enzymes? Enzymes are organic...

Explain what is Enzymes? Enzymes are organic substances that speed up, or catalyze, a chemical reaction. At a given temperature, molecules have varying amounts of energy, and

Define cerebral hemisphere tissue, Q. Define cerebral hemisphere tissue? ...

Q. Define cerebral hemisphere tissue? CEREBRAL WHITE MATTER - The remaining cerebral hemisphere tissue is the deeper cerebral white matter (60% of cerebral volume) which includ

Blood Vessels Assignment, If baroreceptors are primed to detect blood press...

If baroreceptors are primed to detect blood pressure changes and compensate for them, how is it that some patients suffer from chronic hypertension?

Blood transfusion , Blood transfusion  The blood of Raja cannot be t...

Blood transfusion  The blood of Raja cannot be transfused to Rama because the blood group of Raja is ‘B' and blood group of Rama is ‘A'. If Raja's blood with group ‘B' is

Define the features of phylum nematoda, Define the Features of Phylum Nemat...

Define the Features of Phylum Nematoda? Phylum characteristics of Nematoda which are the world's most abundant multicellular organisms are as follows: 1. Nematodes occur in

Organic substances - abiotic components, Organic Substances - Abiotic Compo...

Organic Substances - Abiotic Components These include carbohydrates, proteins, lipids and their derivatives which are derived from the waste products of plants and animals or

What is replication, Question 1 Write a short note on the following- ...

Question 1 Write a short note on the following- Structure of DNA. Satellite DNA Transcription. pBR 322 vector Cytokines Microarrays Question 2 What is

Define the importance of zinc in humans, Define the Importance of Zinc in H...

Define the Importance of Zinc in Humans? Zinc deficiency in humans was reported by A.S. Prasad among people consuming mostly breads and very little animal protein in Middle Eas

Explain tuberculosis, Tuberculosis Tuberculosis is a chronic infectious...

Tuberculosis Tuberculosis is a chronic infectious disease which is caused by a bacterium - Mycobacterium tuberculosis.  It affects the lungs most commonly but call gel localize

Define the structure of vitamins, Define the Structure of Vitamins? Fo...

Define the Structure of Vitamins? For your convenience, however, we have given the structures of these vitamins here in the text. Look at Figure which illustrates the fat-solu

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd