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

Wild type embryo, In Drosophila, the anterior determinant Bicoid is known t...

In Drosophila, the anterior determinant Bicoid is known to activate expression of the gene hunchback in the anterior half of the embryo.  (Bicoid is a transcription factor, which b

Counselling of pace programme, Q. Counselling of PACE programme? Counse...

Q. Counselling of PACE programme? Counselling is a key component of a PACE programme. Counselling is a process that enables a person to identify problems and find a solution or

Sericulture industry, in sericulture industry do which stages of silkworm w...

in sericulture industry do which stages of silkworm weaver buy? why do they do so?

Determine effective half life and value of effective decay, 1. By direct me...

1. By direct measurement of the activity of the thyroid gland in several patients who had received 131 I for diagnostic purposes, it was observed that the biological elimination h

Explain salient features of pulmonary tuberculosis, Salient Features of pul...

Salient Features of pulmonary tuberculosis The salient features tuberculosis include: Wasting of tissues Exhaustion Cough Expectoration, and Fever The acute p

Can serotonin used in consciousness, Q. Can Serotonin used in consciousness...

Q. Can Serotonin used in consciousness? Serotonin complements the action of noradrenalin and acetylcholine in promoting wakefulness and cortical responsiveness. Experiments pro

Explain the true indications of endodontic surgery, Explain the True indica...

Explain the True indications of Endodontic Surgery 1. Failure of non-surgical endo. Re-treatment "persistent lesion" 2. Failure of initial and retreatment will not achieve b

How mineral salts participate in enzymatic activity, Q. How mineral salts p...

Q. How mineral salts participate in enzymatic activity? Many mineral salts are cofactors of enzymes that are the substances without which enzymes do not work.

Analysis of different milk samples, could you please give me a data in the ...

could you please give me a data in the form of tabular column based on milk analysis which can be done in home itself?

Name of the terminal portion of the axon, Q. What is the name of the termin...

Q. What is the name of the terminal portion of the axon? The terminal portion of the axon is called as presynaptic membrane Through, this membrane neurotransmitters are release

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