Three and four kingdom classification, Biology

Assignment Help:

Three and Four Kingdom Classification

The two-kingdom classification, while solving many of the problems of classification, failed to establish clear-cut distinction between plants and animals. It also could not indicate correct relationships among organisms. Difficulty was particularly felt at the unicellular level. There are forms like Euglena and Volvox which possess both plant and animal like characters. On the one had like plants they contain chlorophyll and manufacture their food by photosynthesis.

On the other Kind the" actively swim like animals. Due to this reason zoologists classified them with animals under phylum protozoa while botanists included them as plants under Thallophyta. In addition to this, there are some other organisms like Peranema which closely resemble Euglena in structure but lack chlorophyll. These are not included among plants but were always classified under Protozoa. In order to overcome such difficulties, Haeckel (1866) proposed setting up of a third kingdom under the name Protista (meaning the very first) to include all thallophytes and protozoans. This kingdom also included bacteria and blue-green algae. According to this system the old kingdom Plantae included only the members of Embryophyta while Animalia was left only with Parazoa and Metazoa. However, many forms such as blue-green algae and bacteria of Protista lack membrane- bound nuclei. So, a fourth kingdom, Monera, was later established by Whittaker in order to accommodate these forms. From the evolutionary point of view the kingdom Monera is regarded as the most primitive.


Related Discussions:- Three and four kingdom classification

Define interaction of vitamin c with riboflavin, Define interaction of Vita...

Define interaction of Vitamin C with Riboflavin? The two coenzyme forms of riboflavin are FMN and FAD. They are found in a large number of systems which function in the metabol

T or F, The role of ATP hydrolysis in actin polymerization is similar to th...

The role of ATP hydrolysis in actin polymerization is similar to the role of GTP hydrolysis in tubulin polymerization: both serve to weaken the bounds in the polymer and thereby pr

What are the phases to atherosclerosis, Q. What are the phases to atheroscl...

Q. What are the phases to atherosclerosis? There are five phases to atherosclerosis: Phase I: Asymptomaticphase, consists of fatly streaks which are non-obstructive, lipi

Reproduction, What is the difference between asexual and sexual reproductio...

What is the difference between asexual and sexual reproduction

Explain tropical rain forests in biomes, Explain Tropical Rain Forests in b...

Explain Tropical Rain Forests in biomes? You probably are well aware of the danger that the world's rain forests are facing in terms of extinction! There are huge numbers of sp

What is the inactivation of the x chromosome, What is the inactivation of t...

What is the inactivation of the X chromosome? What is a Barr body? Inactivation of the X chromosome is a phenomenon that happens in women. As women have two X chromosomes only

Lactation tetany of mares (eclampsia, Lactation tetany of mares (eclampsia,...

Lactation tetany of mares (eclampsia, transit tetany) Hypocalcaemia in mares causes lactation tetany, which is characterized by abnormal behaviour, in coordination and tetany.

Define the future challenges of spatial processes, Define the Future challe...

Define the Future challenges of spatial processes? Understanding the dynamics of stochastic spatial systems, systems with a multitude of spatial scales, and systems along with

Explain dietary management, Dietary Management The golden  rule  in  th...

Dietary Management The golden  rule  in  the dietary  management  of  ally  fever  is  "feed  the fever". Considering that  enteric (typhoid) fever  is accompanied by anorexia,

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