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.
About 90% of ozone of atmosphere resides in stratosphere (16 to 40 km) layer of atmosphere as ozone layer. It protects life on this planet from harmful U.V. radiations. In absence
A sample of yeast cells was serially diluted 1/10 five times then serially diluted 1/3. the number of yeasts was338 yeasts per ml. what was the original concentration? Please show
Write down all the four quantum numbers of the electron in the outermost shell of rubidium (At. no.= 37) atom. a) What type of hybridization is associated with N in NH 3 ? b
Transport with the Help of Membrane Protein Even though, the lipid bilayers do not permit the entry of polar molecules such as ions, sugars, amino acids, nucleotides and cell
Define Reflection - Endodontic Surgery - Marginal gingival is very delicate and easily injured, therefore you should begin reflection of the vertical incision in the attached
Neurulation in Amphibians The first step in the neurulation process is the flattening and thickening of dorsal ectoderm to form neural plate. The plate of cells are different
Define Importance of nutritional requirements for management of emergencies? Knowledge of nutritional requirements for management of emergencies is therefore, important due to
Concerning the sex chromosomes of the XY system which type of gamete do the male and the female individuals respectively produce? An Individual of the female sex is XX and thus
Poverty and Malnutrition Poverty and malnutrition are closely related. As noted before, many elementary aspects of being poor like hunger, inadequate health care, unhygienic l
Explain the Control of Air Pollution a. Air belongs to everyone Need it to treat air pollution as public problem b. Air pollution is an inevitable concomitan
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