Segmentation - metazoa, Biology

Assignment Help:

Segmentation - Metazoa

Segmentation or metamerism is the division of the body into smaller transverse compartments along the anterior-posterior axis. Segmentation is widespread among animals, with true segmentation occurring in annelids, arthropods and most chordates though some other groups show superficial segmentation of ectodermal body wall. Fundamentally there are three body forms. First, monomeric where there is no division of the large body cavity at all. Ascaris has this type of body form. Second, oligomeric where the body cavity is divided into three and each region has a separate body cavity hooks with no divisions on the abdomen Phorona is a warm with this body plan'. Third metameric in which the body is divided into head, thorax and abdomen and where abdomen is further divided into a chain of segments.

2177_Segmentation - Metazoa.png

                                                        Figure: superficial segmentation seem in tape-worms

A Segmented body forms can be seen in tape worms, annelids arthropods and' chordates. Of these segmentation in tape worms is quite different from that seen in the others. We can observe that segmentation in tape worm is superficial, a series of ring like creases develop in the cuticle and the body wall which facilitate bending and telescoping of the body. But this segmentation is strictly ectodermal and this segmentation is a reproductive adaptation. The segments of the entire body are in a continuous process of being produced matured and discarded. The new segments grow in the neck region and the older ones are detached from the posterior end, Each segment functions as an independent unit without having' any vital connections with the other.


Related Discussions:- Segmentation - metazoa

Major parts of the human ear, Q. What are the major parts of the human ear?...

Q. What are the major parts of the human ear? The human ear is divided into three major parts: the external ear, the internal ear and the middle ear.

Digestive system, describe secretory function of salivary gland

describe secretory function of salivary gland

Chemical properties of fatty acids, Chemical Properties of Fatty Acids ...

Chemical Properties of Fatty Acids Esterification Like any other organic acid,  fatty acids also form esters with  various alcohols. An alcohol such as glycerol is reacted

Verify where recombination happens along a chromosome, In a follow up to Al...

In a follow up to Alfred Sturtevant's studies on recombination in the fruit fly, Seymour Benzer used complementation studies of bacteriophage mutants to verify where recombination

Fats requirements during congestive cardiac failure, Q. Fats requirements d...

Q. Fats requirements during congestive cardiac failure? Fat: The quantity and quality of fat would be governed by the severity of hyper- lipidemia and adiposity. Emphasis, as

Define effect of minerals on athletes, Define effect of Minerals on athlete...

Define effect of Minerals on athletes? Mineral supplementation, particularly iron in cases of iron deficient athletes is beneficial. Similarly, magnesium and chromium supplemen

Endocrine organs, Endocrine Organs Endocrine organs, as explained ear...

Endocrine Organs Endocrine organs, as explained earlier are those organs or tissues, which release chemical substances directly into blood stream. Not like exocrine glands th

What are the moderate intensity exercises, Q. What are the moderate intensi...

Q. What are the moderate intensity exercises? - Walking for 1/2% hr or jogging - Biking leisurely for 1/2 hr. - Playing tennis, swimming, gardening, golfing - Vacuumin

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