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

Define about the anthropometry method, Define about the Anthropometry Metho...

Define about the Anthropometry Method? Anthropometry refers to the measurement of the size and proportions of' the human body. Anthropometric prediction equations estimate body

Female reproductive system, FEMALE REPRODUCTIVE SYSTEM - In female mamm...

FEMALE REPRODUCTIVE SYSTEM - In female mammals the female reproductive system characteristically comprises of the ovary, uterus, placenta, vagina and vulva.

Chemolithoautotrophs - nutritional types of microorganisms, Explain Chemoli...

Explain Chemolithoautotrophs - Nutritional Types of Microorganisms These microorganisms use inorganic compound as source of energy and electron and CO 2 as a source of carbon.

Define dietary factors with antinutritional effects, Define Dietary Factors...

Define Dietary Factors with Antinutritional Effects? In the above sections, we have learnt about a variety of food components having a host of health promotive properties. Let

Senescence - effects of plant growth regulators, Senescence - Effects of Pl...

Senescence - Effects of Plant Growth Regulators on Development All five major growth regulator groups: auxins, gibberellins cytokinins, abscisic acid and ethylene can influenc

Homomorphic types - intra specific incompatibility, Homomorphic Types - Int...

Homomorphic Types - Intra specific Incompatibility It is characterized by morphologically indistinguishable mating types within a species. A proper breeding is required for th

Induction in metamorphosis, Induction in Metamorphosis Some of the mo...

Induction in Metamorphosis Some of the morphogenetic changes throughout metamorphosis are found fo be quite independent of hormone action. For instance, generally during meta

Ecology, Which of the following are likely to help conserve soil and preven...

Which of the following are likely to help conserve soil and prevent erosion?

Leptospirosis, L e p t o s p i r o s i s It is zoonotic dis...

L e p t o s p i r o s i s It is zoonotic disease characterized by interstitial nephritis, haemolytic anaemia and abortions. E t iology : The disease i

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