Limitations of five-kingdom classification, Biology

Assignment Help:

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.


Related Discussions:- Limitations of five-kingdom classification

List the goals of management of type 1 diabetes mellitus, Q. List the goals...

Q. List the goals of management of Type 1 Diabetes Mellitus? Goals of management of Type 1 Diabetes Mellitus: a) to keep blood sugar level as close to normal as possible.

Define the management of epileptic patients, Define the Management of Epile...

Define the Management of Epileptic Patients? The primary treatment of epilepsy is anticonvulsant drugs. The focus of nutritional management is a diet, which is appropriate for

Multiple alleles, MULTIPLE ALLELES (i)         More than two alternativ...

MULTIPLE ALLELES (i)         More than two alternative forms (alleles) of a gene in a population occupying the same locus on a chromosome or its homologue are known as multiple

What is tricuspid valve annuloplasty, Q. What is Tricuspid valve annuloplas...

Q. What is Tricuspid valve annuloplasty? It depends upon the cause of tricuspid regurgitation. Specific therapy is directed towards the particular cause of pulmonary artery hyp

Planning of diabetes counselling, Q. Planning of diabetes counselling? ...

Q. Planning of diabetes counselling? You have helped the client to find out various solutions to a problem and understand the coping skills, ensured support from the family  su

Zoology, what does ICZN stand for

what does ICZN stand for

Energy demand for active or moderately active lifestyles, Energy demand for...

Energy demand for Active or moderately active lifestyles? These people have occupations that are not strenuous in terms of energy demands, but involve more energy expenditure t

Structure of the cilia and flagella, Normal 0 false false f...

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

Insulators - transgenic animals, Insulators Numerous experiments showed...

Insulators Numerous experiments showed that a transgene is generally poorly expressed when it contains a cDNA rather than the corresponding genomic DNA; when it is integrated a

What is endocytosis, Which of the following is true for endocytosis? A....

Which of the following is true for endocytosis? A. During endocytosis of GLUT4 transporters in fat cells, there is removal of GLUT4 transporters from plasma membranes. B. Du

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

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!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd