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!
Origin and Evolution of Metazoa
Most of the early metazoans were soft bodied and so their fossils are rare. The extremely fragmented fossil record does not shed any specific light on their origin. Therefore, 'most of the explanations on their origin are based on their embryology and -comparative morphology. A series of theories have been put forward to explain the origin of multicellular metazoans from unicellular organisms. Of these, three principal theories could be considered.
1) Syncytial Theory: That the ancestral metazoans have arisen from a multinucleate. ciliate by compartmentalization or cellularization.
2) Colonial Theory: That the ancestral metazoans have arisen from colonial flagellates by cellular specialisation and interdependency.
3) Polyphyletic Theory: That the metazoans have arisen from more than one group of organisms.
Characters of pennetula
What is the photoperiodism? The Photoperiodism is the biological response presented by some living beings to their daily time of light exposure (photoperiod).
What are fossil fuels? Fossil fuels, like oil, gas and coal, form when organic material is preserved from the complete action of decomposers, generally buried deep and under pr
Bacteria: Bacteria have a protective covering called 'cell wall'. Beneath this. there is a plasma membrane which encloses protoplasm of the bacterium containing various types
Explain the Nutrition of Women during Pregnancy? During the post-war years, the people in the developed world recognized that women were at a disadvantaged position and felt th
Closed Type of Circulatory Systems Some non-chordates, like cephalopods (octopuses, squids), earthworms, polychactes and all vertebrates have a closed circulation along with b
The risk for IE among IV drug abusers, 2 to 5 per cent per patient- year, is estimated to be several fold greater than that of patients with rheumatic heart disease or prosthetic v
Conjugation - Patterns of Sexual Reproduction Conjugation is a temporary union among two individuals of the same species, during which the original macronucleus disintegrates,
what is plasmodium
Each ribosome having of two subunits a small subunit and a large subunit, every of that is a multi component complex of rRNAs (ribosomal RNAs) and ribosomal proteins t
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