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

Nuclear run-on, Nuclear run-on is a technique used to estimate the relativ...

Nuclear run-on is a technique used to estimate the relative rate of the transcription of a given gene, as opposed to steady-state level of the mRNA transcript (which is influenced

Active transport, Active transport is the transport of the molecules again...

Active transport is the transport of the molecules against the concentration gradient (from area of low concentration to area of high concentration) with the help of proteins in t

Explain the factors that lead to vitamin k deficiency, Explain the factors ...

Explain the factors that lead to vitamin K deficiency? The factors that lead to vitamin K deficiency include: 1) Marginal dietary intake if one undergoes trauma and extensiv

Explain the anabolic phase - dietary management for burns, Explain the Anab...

Explain the Anabolic Phase - Dietary Management for Burns? During this period the patient is well hydrated and the reactions due to metabolic stress are under control. The pati

What is the formula of the dpd for withered plant, Q. What is the formula o...

Q. What is the formula of the DPD for withered (shrunken) plant cells and how is that situation possible? Withered plant cells are those that have shrunk due to loss of water b

Would induction of CYP 2E1 raise your blood alcohol level?, If I take a dru...

If I take a drug that induced the synthesis of CYP 2E1 in my system, would that raise or lower my blood alcohol level after I drink a beer or wine (compared to if I hadn''t taken t

Characteristics of a good fuel, (1)   It should have high "calorific value"...

(1)   It should have high "calorific value" or heat content. (2)   It should have "moderate ignition temperature". (lgnition temperature is the minimum temperature at which it s

Explain the nutritional management of eating disorders, Explain the Nutriti...

Explain the Nutritional Management of Eating Disorders? Good nutritional management of patients with eating disorders requires attention to a number of areas. It is important t

Scentific american article suggests some improvements, The human skeleton h...

The human skeleton has evolved from that of four-legged animals. Unfortunately, the adaptation is far from perfect; thus, our upright posture causes problems like backage and the k

Explain alginate, Alginate Alginates are produced by brown seaweeds (Ph...

Alginate Alginates are produced by brown seaweeds (Phaeophyceae, mainly  Laminaria).  Alginates or algin, is a generic term for the salts and derivatives of alginic acid. Algin

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