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

Leaves give off water vapour, Leaves give off water vapour Use two same...

Leaves give off water vapour Use two same pots of soil, one with a small plant and the other without. Cover the soil in every pot with cardboard as shown in the diagram after w

Give examples of diseases caused by bacteria, Give three examples of diseas...

Give three examples of diseases caused by bacteria, Diseases caused by bacteria contain tonsillitis, blood poisoning, scarlet fever, tuberculosis, typhoid, diphtheria, food poi

Exercise and medications in bronchial asthma, Exercise Stress or em...

Exercise Stress or emotional upset  Medications Aspirin, non-steroidal anti-inflammatory drugs(NSAIDs), beta- blockers(including eye drops), cholinergic dr

Cause the inhibition of apoptosis, We now understand that mutations that ca...

We now understand that mutations that cause the inhibition of apoptosis are found in tumors. Because proliferation itself is not induced by the inhibition of apoptosis, explain how

Phycomycosis (zygomycosis), Phycomycosis (zygomycosis) Zygomycosis (pr...

Phycomycosis (zygomycosis) Zygomycosis (previously known phycomycosis) involves fungi belonging to genera Mucor, Rhizopus, Absidia, Entomophthora, Mortierella and Basidiobolou

Radiation cataract and steroid induced cataract of the eye, Explain the rad...

Explain the radiation cataract and steroid induced cataract of the eye. Radiation Cataract Exposure to radiation causes discoid posterior sub-capsular opacities. Mechanism o

The halstead-reitan neuropsychological battery, The halstead-reitan neurops...

The halstead-reitan neuropsychological battery The beginnings of the battery can be traced to the special laboratory established by Halstead in 1935 for the study of neurosurgi

How would you confirm this disease, Question 1 A patient is admitted to th...

Question 1 A patient is admitted to the hospital with suspected pulmonary tuberculosis. How would you confirm this disease? Answer the following questions                   a)

Ornithosis (psittacosis), Or nit h o s i s (psittacosis) This is ...

Or nit h o s i s (psittacosis) This is an important zoonotic bacterial infection and causes disease in humans and birds. Collectively, these conditions are called as chla

Show the energy pyramids, Q. Can the amount of available energy in a given ...

Q. Can the amount of available energy in a given trophic level be larger than the available energy in inferior trophic levels? What does that condition means to the conformation of

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