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!
Syncytial Theory - Metazoa
This theory suggests that the ancestral metazoan was at ,first Syncytial in structure but later became cellularised by formation of cell membranes around individual nuclei this producing a typical multicellular body. Hadzi (1953) and Hanson (1977) have been the chief proponents of this theory. As many ciliates tend to have a bilateral symmetry, the advocates of this theory maintain that the ancestral metazoan was bilaterally symmetrical similar to the present day acoelous flatworms. The theory receives support from the fact that acoelous flatworms are
Figure: Possible routes for evolution of animals
There are several objections to this theory. It ignores the embryology of flatworms in which nothing similar to cellularization occurs, nor does it explain the presence of flagellated sperms in metazoans. Perhaps the most important objection to this theory is that it assumes that .acoelous flatworms are the most primitive metazoans and therefore, presumes bilateral symmetry to be more primitive than radial symmetry and thus radial coelenterates must have been derived from bilateral flatworms. But then it is accepted that radial symmetry is more primitive than bilateral symmetry and radial coelentrates could not have evolved from flatworms.
EVIDENCES OF EVOLUTION - The evidences of organic evolution derived from many lines of study indicate that present day forms have arisen by gradual changes from pre existing fo
Vitamin A dry powder Vitamin A dry powder is used in the (manufacture of dry mixtures) for which the oily ester concentrates are unsuitable or undesirable. Mainly, they are inc
F o o t - a n d - m o u t h disease Foot-and-mouth disease (FMD) is an extremely contagious viral disease of cloven footed animals most notably cattle, pig and she
Determine Energy demand for Vigorous or vigorously active lifestyles? These people engage regularly in strenuous work or in strenuous leisure activities for several hours. Exam
Maedi/visna Maedi, a progressive pneumonia, and visna, a neurotropic disease, found in sheep and goats are caused by the Maedi/visna virus, belonging to the family Retroviridae
Q. How to investigate aortic stenosis by Cardiac Catheterization? The indications are to confirm hemodynamics when the non-invasive tests are not conclusive or there is a disc
How does the addition of a watery secretion to the contents of the gut help in the process of digestion?
In unilocular ovary with a single ovule tje placentation is??
Define Feeding for Infants of HIV/AIDS Mothers? It is recommended to continue breast-feeding even if the disease will continue to be transmitted. If these infants are not breas
In an experiment, it was necessary that you determine the concentration of dsDNA by using a spectrophotometer. You used 6 microliters of your purified dsDNA, and the reading at OD=
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