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.
Spray-drying method Spray-drying is the common drying method in the production of ISP. The primary physical form of ISP in commerce, is that of fine powders. Structured form
Achondroplasia is an autosomal dominant disorder associated with a gene on chromosome 4. Sickle cell anemia is due to a gene on chromosome 11. A man and a woman with achondroplasia
What is the best microscope to get a detailed view of the parts inside of a preserved plant cell?
How do the repairing enzymes of the genetic system act? There are enzymes within the cells that detect errors or alterations in DNA molecules and start a repair of those errors
Describe Class Diplopoda and Chilopoda in detail? Members of the Subphylum Crustacea and the Subphylum Uniramia have one major characteristic in common. Both groups have biting
Q. Describe Sensory Receptors? Receptor organs can detect external or internal stimuli. They can be classified according to the stimulus to which they respond: • Photorecep
(a) What do you understand by the term 'accommodation'? (b) What part does the lens play in this process? a) Accommodation is the way the eye can focus either
ALEURONE GRAINS - Also known as Plant lysosome , because they contain hydrolytic enzymes. Consists of Proteins. They are also known as Aleuroplast because they are ric
Which of the following is true for a toe motor neuron that excites a toe muscle that moves the big toe in the right foot? A. The cell body of the toe motor neuron is located in
differences of plants and animals in terms of form and structure?
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: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd