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

What are the major plant tissues, What are the major plant tissues that for...

What are the major plant tissues that form the rings observed on stem sections of some trees? The rings observed on a stem cross section of the dicot trees are made of conducti

Mesophytes, Mesophytes These plants grow in moist habitats and well-aer...

Mesophytes These plants grow in moist habitats and well-aerated soils. They prefer soil and air of moderate humidity but fail to swive in areas with water-logged soils or oveta

What is organelles, What is Organelles? Organelles :   Eukaryotic cel...

What is Organelles? Organelles :   Eukaryotic cells contain various membrane-bound structures called organelles, in contrast to prokaryotes, which lack a definite internal or

What is inflammation, What is inflammation? Inflammation is the initial...

What is inflammation? Inflammation is the initial response of the unspecific defense system versus aggressions against the body (the aggressions might be caused by infectious p

Explain bruce protocol, Q. Explain Bruce Protocol? Bicycle Ergometry ...

Q. Explain Bruce Protocol? Bicycle Ergometry Most bicycle test are performed sitting upright, but supine bicycle test have become more popular. Treadmill Test The

Define interaction of vitamin c with pyridoxine, Define interaction of vita...

Define interaction of vitamin c with Pyridoxine? Pyridoxine is involved in glyconeogenesis through its action in transaminase reactions. Low levels of pyridoxine impair glucose

Show the properties of food, The food components are in the form of solids,...

The food components are in the form of solids, in solutions or in the form of colloids - sols or emulsions. The properties of these components determine the quality of food. The

Polynephritis in cattle, Polynephritis in cattle Contagious bovine pol...

Polynephritis in cattle Contagious bovine polynephritis is a specific infection of urinary tract of cattle. The causative agent is Corynebacterium renale, a rod shaped gram-po

Define the process of digestion of proteins, Define the Process of Digestio...

Define the Process of Digestion of Proteins? The daily protein intake (of about 50-100 g) and the protein of enzymes, sloughed (bled or drop off) epithelial cells and mucins, w

Which terrestrial vertebrate group is extremely rare deserts, Which terrest...

Which terrestrial vertebrate group is extremely rare in deserts? The Amphibians are terrestrial vertebrates very rare in desert environments (although there are a few species a

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