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.
Explain the term- Cerebral Ischemia Ischemia refers to any of a group of disorders in which the symptoms are caused by vessel blockage preventing a sufficient supply of blood t
Glycogenolysis: It is breakdown of glycogen to glucose by means of the reaction series shown in figure 6.11 Like glycogenesis it also occurs in all body cells , But
Which of the following serves as an effector, or as part of an effector, that functions in a negative feedback system? A. Muscarinic Acetylcholine Receptors (mAChRs) in the SA
Define Developments in the Area of Nutrient-Gene Interactions? This unit introduces you to the recent developments in the area of nutrient-gene interactions. We will first revi
Growing roots from different parts of plants Secure a box of sand and place it away from direct sunlight. Wet the sand thoroughly and keep it moist. Plant the following thi
Q How does water move in sponges? What is the function of the pores in these animals? Sponges are filtering beings they make water enter their bodies by their lateral pores. Wa
Explain Urine Urea Nitrogen - Nutrition during Stress? 5 gm/24 hrs. = No stress 5 to 10 gm/24 hr = mild hyper-metabolism or level 1 stress 10 to 15 gml24 hrs = moderat
Q. What is a nutrient? A nutrient is every substance used in the metabolism and which is obtaining from the diet. For example, essential amino acids and vitamins are nutrients.
Q. How can the knowledge about fermentation describe the origin of muscle cramps and pains after intense physical exertion? A typical fermentation process due to oxygen scarcit
Define Food Science and Simple Sugars? This first unit introduces the concept, scope and importance of food science and technology as a discipline. It further presents a detail
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