Metamerism or segmentation, Biology

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).

Posted Date: 2/2/2013 12:26:58 AM | Location : United States







Related Discussions:- Metamerism or segmentation, Assignment Help, Ask Question on Metamerism or segmentation, Get Answer, Expert's Help, Metamerism or segmentation Discussions

Write discussion on Metamerism or segmentation
Your posts are moderated
Related Questions
Uses of Grafting Grafting helps to preserve and perpetuate varieties that cannot reproduce by vegetative method. Grafting changes less useful varieties to more desirable

How many asymmetric carbons are there in ribose and glucose?

CHLAMYDIOSIS Amongst various causes of morbidity and mortality chlamydiosis is recognized as one of the important infectious conditions and emerging as threat to the livestock due

Q. How is the respiratory system in aquatic molluscs characterized? What adaptive respiratory structure do terrestrial molluscs present? In terrestrial molluscs the rich vascul

Define protein requirements of children up to age of 2 years? Infants and children up to age of 2 years should consume about 40% energy from fat (i.e. 40 en%). Fat is an import

Pachytene: The pairing of homologous chromosomes is completed. Chromosomes become more and more thick. Each bivalent has four chromatids , which wrap around each o

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

According to Mendel's law phenotypical characteristics would be verified by pair of factors (alleles) that separate independently in gametes. What are the main types of inheritance

How do the products of meiosis I differ from those of meiosis II? In meiosis I, the offspring cells are haploid but every cell contains two copies of the chromosome because th

What are the organic chemical groups that characterize carbohydrates? How are carbohydrates classified according to the presence of those groups? Carbohydrates are also called