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.
INTRODUCTIO N - Fertilization is a complex process which involves fusion of male & female gametes. The male gamete in animals is called as sperm & the female gamete as o
Actions of Estrogens The most general effect of the estrogens is to promote tissue growth. It is more pronounced in the accessory sex tissues. Estrogens stimulate cell divi
Evaluating the degree of urinary obstruction: D.P. is a 63-year-old man who has been experiencing progressive difficulty with initiating the urinary stream and frequently needs to
Prevention of Accidents - Accidents and Losses The theories of accident causation explained earlier serve as good guide to prevent accident. The factors that may cause acciden
How do you determine net atp production after complete oxidation to CO2 and H2O using mitochondrial?-oxidation, the TCA cycle, the mitochondrial electron transport chain and oxidat
Q. Investigation of Tricuspid regurgitation by Echo Doppler? Investigations ECG in secondary TR shows evidence of right atrial overload and right ventricular hypertrophy
RAP can be determined semiquantitatively by assessing collapse of the inferior vena cava during inspiration. The inferior vena cava is imaged subcostally and its diameter is exa
Explain the Skeletal System? Skeletal System: The support framework, or skeleton, in the human body is composed of mostly hard mineral substances. Unlike crustaceans or insec
Long-Day Plants (LDP) - Plant Responses to Light-Dark Cycles The definition of this is exactly opposite to short-day plant. That is those plants which flower when given more t
Define the Buffer capacity - Nutritional Biochemistry? Buffer capacity can be defined as, 'the capacity of a solution to resist changes in pH on the addition of strong acid or
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