Metamerism or segmentation, Biology

Assignment Help:

Metamerism oe Segmentation

In the early coelomates the coelom was not divided into segments, the whole body cavity was a single space. Hence body movements were not precise. Though with evolution, coelom became divided into a number of chambers through partitions or septa made up of the mesodermal lining, the peritoneum. This increased the efficiency and precision of body movements, like individual segments could be moved more precisely now, with the same mechanism viz., hydrostatic or hydraulic pressure. As well, each segment came to have a repetition of many other organ systems such as circulatory, excretory, reproductive aid nervous systems. Each body segment is so more or less a repetition of the other and hence redundant; the animal can survive and function generally even if a few segments were lost. This phenomenon of divisions of body into a series of much more or less identical segments each containing a section of approximately all systems, is known as segmentation or metamerism. Each section of the body is termed as a segment or metamere. Metamerism has evolved independently at least two times in the animal kingdom in protostomes (Annelida - Arthropoda) and in Deuterostome (vertebrates).


Related Discussions:- Metamerism or segmentation

Imaginal discs, Imaginal Discs In the holometabolous larva, there are ...

Imaginal Discs In the holometabolous larva, there are two cell populations: (1) The larval cells that are used for the larval structures and (2) The imaginal disc and th

What are the illustrations of the criminal law, What are the illustrations ...

What are the illustrations of the criminal law? Illustrations of crimes' law: Illustrations of crimes are theft, reckless or murder behaviour. The major aim of illegal

Determine guidelines for planning balanced diets for elderly, Determine Gui...

Determine Guidelines for Planning Balanced Diets for Elderly? The key element in planning diets for the elderly should be nutrient-based dietary guidelines, in order to reduce

Which joint is stronger-the shoulder or hip joint, In general compare and c...

In general compare and contrast the three functional classifications of joints according to movement. What are two characteristics that make synovial joints unique and different fr

Tricuspid valve replacement, Tricuspid Valve Replacement :  It is don...

Tricuspid Valve Replacement :  It is done for organic tricuspid valve disease and at times for functional tricuspid I regurgitation. When done along with other procedures, it

Where do most allergic reactions occur, Most of them happen on mucous membr...

Most of them happen on mucous membrane. Allergens enter the body by the process of inhalation or ingestion.

Determine the osseus defects around implants, Osseus defects around implant...

Osseus defects around implants. They are classified into four main groups. Group I defects: These demonstrate moderate horizontal bone loss with a minimal intrabony component

Explain nutritional requirements of microbes, Explain Nutritional Requireme...

Explain Nutritional Requirements of Microbes? Microorganisms require various nutrients and physical factors for their existence and growth. Nutrients are substances used in bio

Coronary revascularization, When underlying coronary artery disease is the ...

When underlying coronary artery disease is the cause of heart failure in the coronary revascularization may both improve symptoms and prevent  progression. Patients with angina and

Explain main reason for the anomalous behaviour of lithium, How does chemic...

How does chemical adsorption of a gas on a solid vary with temperature? a) Mention the main reason for the anomalous behaviour of lithium in Group of the periodic table.

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