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.
"In these autotrophs, sporophyte is the dominant generation. Gametophyte is also photosynthetic and not dependent on sporophyte for nutrition." These autotrophs are: a. P
MUTATION THEORY (Hugo de Vries 1901) - New species are not formed by continuous variations but sudden appearance of variations i.e., mutation. Mutation are heritable and per
N A TURA L CONTROL OF POPULATION GROWTH - 1 . Biotic potential - It is capacity of population to increase its number by reproduction. For all animals, it is v
Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4
State the phases of soil genesis Soil genesis embodies two distinct phases. One is weathering that involves disintegration and decomposition of rocks and minerals, the other is
Mixed Mitral Stenosis and Regurgitation The most common cause for a combined lesion is rheumatic, Very rarely; it could be of congenital origin. Regurgitation in a stenotic val
Echocardiography Utilizes principle of ultrasound for visualization of heart and great vessels. It uses sound in the frequency of 1-10 MHz. As the frequency of probe increase
Q. Important aspect of dietary management during hypertension? Most important aspect of dietary management i.e. the intake of minerals and electrolytes, which are closely assoc
Q. Concerning enzymatic reactions, how dissimilar are the graphic curve of the variation of the speed of a reaction as function of substrate concentration and the curve of variatio
IS Neuron B in the frog central nervous system Consider Neuron B in the frog central nervous system whose plasma membrane has a previously unknown channel that is selectly cond
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