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!
Limitations of Five-Kingdom Classification
As already pointed out, each system of classification has its own limitations. The two-kingdom system has outlived its usefulness as it could not do justice to forms like Euglena and Volvox. The three-kingdom classification failed to accommodate properly prokaryotic forms. The limitation of the four-kingdom classification was that despite creation of kingdom Monera it failed to account for the intergradations between Protista and Animalia.
The present five kingdom system is also not the final solution to the problems of taxonomy. In this system too we have many weaknesses despite the acceptance of this system by most biologists. The exclusion of Protozoa from the animal kingdom, in this system concerns many zoologists. Protozoa share many characteristics with Metazoan animals. Most ingest their food; many have specialised organelles and advanced locomotory systems; many reproduce sexually and some flagellate protozoa are colonial with division of labour among cell types. Indeed, there is little doubt that metazoan animals evolved from one or more protozoans groups. Thus zoologists though accepting that are eukaryotic protists and not animals according to the five kingdom classification, still continue to claim Protozoa as their own. This system is also not able to show clearly the inter-relationships of various groups in all instances. Even now many phyla contain forms whose relationships are not clearly understood. among nonchordates the grouping collectively called Minor phyla has unsolved problem of phylogenetic placement. Recently, many biologists have also tried to split the kingdom Monera into two: (i) Eubacteria and (ii) Archaebacteria, leading thus to the proposal of six kingdoms. In fact, during the past twenty years various revisions in the classification system have been discussed with the number of kingdoms ranging from 3-13. Biologists generally follow the five-kingdom-classification despite its inadequecies because it appears to be the most acceptable system today and indeed the most convenient one available.
In the human body, the potassium ion can pass easily through cell membranes, yet the potassium ion concentration is higher inside many cells than it is outside these cells. Could t
Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4
Circulation of nutrients in the coastal zone Circulation of nutrients from the sea bottom to the upper surface, occurs in the coastal regions by two processes Upwelling
difference between anaerobic respiration and fermentation
Erythropoietin (EPO) A. acts by increasing the production of red blood cells by cells in the bone marrow. B. is secreted by peritubular interstitial cells of the kidney cort
Q. Why is the cytoplasm of sperm cells very reduced? Why do mitochondria of sperm cells concentrate in the base of the flagellum? The reduced cytoplasm of sperm cells reduces t
Quick transient responses - Behaviour of Plants Such responses are stimulated by factors showing significant variations over relatively small time period e.g., those showing w
Non-concomitant or Paralytic Squint This subdivision of manifest squint occurs when there is a deviation of the eye in different directions. The causes for non-concomitant squ
How are the transparency and functions of cornea evaluated? Physiological roles of barrier function, refractive function (with interaction of tear film), response to wound and
Viral haemorrhagic fevers (VHF) Viral haemorrhagic fevers (VHF) are caused by a diverse group of viruses belong to the families Arenaviridae, Bunyaviridae, Filoviridae and Fla
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