Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Regional Specialisation
Regional specialisation takes place usually by three processes –
1) Restriction of certain structures to a few segments, for example, gonads are restricted to a few specialised genital segments in annelids (e.g. earthworm).
2) Structural divergence of segmental structures to perform different functions. For example some segmental appendages may be modified from those suitable for locomotion to those adapted for grasping or chewing, (e.g. insects)
3) Fusion of segments along the length of the animal. For example, fusion of anterior segments to form the head. The head of Nereis consists of the acron and two other segment while that of Drosophila is composed of five segments.
The second significant feature of metameric segmentation is its importance in the ' locomotion of soft bodied animals. The acoelomates animals use their musculature of longitudinal and circular muscles for locomotion but the evolution of a coelomic cavity has allowed the fluid to act as hydraulic skeleton. In invertebrates like annelids, muscles of the body wall act against this pressure. When circular muscles Contract, hydrostatic pressure on coelomic fluid will result in lengthening of the body; when longitudinal muscles contract, it will result in widening of the body. Since metameric segmentation results in compartmentalisation of the body, this elongation and widening of the body can be restricted to a few segments at a time.
This local change in the shape of the elongate body increases the locomotory efficiency. The broadened part of the body can be firmly fixed against the burrow especially if there are clinging structure such as setae and the lengthening of the body will produce considerable thrust resulting in progression of the animal. Thus the alternate peristaltic waves enable the animal to move forwards faster and efficiently.
Excretory organ of agama lizard
How emulsion can stabilized Emulsions can be stabilized by the use of emulsifiers, finely divided particles adsorbed at the interface and water dispersible hydrocolloids. Emuls
Who is the founder of theory survival of the fittest ?
Is gene a triplet of consecutive DNA nucleotides A gene isn't a triplet of DNA nucleotides with their respective nitrogen-containing bases, like CGT or AAG. The nucleotide trip
Q. Explain Spoilage of Fruits and Vegetables? Ans. Fruits and vegetables are an integral part of daily diets of man all over the world. The spoilage of fruits and vegetabl
The allele that causes albinism (p) is recessive to the allele for normal pigmentation (P). A normal woman whose father is an albino marries an albino man whose parents are both no
What is Coelom - Body Cavity explain? Among the bilaterally symmetrical organisms, animals have three different types of body plans with respect to body cavities. The term coel
What is HMP pathway The HMP pathway like glycolysis occurs in the cytosol of the cell. However, C02 which is not produced in glycolysis, is a characteristic product in HMP
WHAT TRAITS ALLOWED VASCULAR PLANTS TO GROW TALL
The second category of isolating mechanism that may permit interspecific mating but ensures reduced viability is called post-mating isolating mechanism. This category could be subd
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!
whatsapp: +1-415-670-9521
Phone: +1-415-670-9521
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd