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

Explain techniques for broken instrument removal, Explain Techniques for Br...

Explain Techniques for Broken Instrument Removal Described by Gary Carr Staging platform (cutting in flat surface) a) Create straight line access to separated file using mod

Genomic dna from the sea urchin, Eric Davidson isolated and compared the se...

Eric Davidson isolated and compared the sequences of mRNA transcripts and genomic DNA from the sea urchin. Which of the following is a true statement regarding his findings? A.

Determine the amount of vasopressin, Consider the case of a rare mutant in ...

Consider the case of a rare mutant in which the concentration of solutes in the kidney medulla interstitial spaces is equal to the concentration of solutes in the liquid in the lum

Tissue organization and specialized organs, Q. Do plants have tissue organi...

Q. Do plants have tissue organization and specialized organs? Plants have specialized organs (like roots, limbs, reproductive organs, leaves) and differentiated tissues (suppor

State the copious sterile saline irrigation, Using copious sterile saline i...

Using copious sterile saline irrigation This can be delivered from a sterile infusion bag in a pressure cuff or a peristaltic pump. The drills can be adequately cooled by spray

What are trends of the gametophyte in the evolution of plant, What are tren...

What are trends of the gametophyte in the evolution of plants? The tendency of the gametophyte evolution in plants has been towards the formation of gametes that are self-dete

Muscular tissue, MUSCULA R TISSUE Muscular tissue in general develop...

MUSCULA R TISSUE Muscular tissue in general develops from the mesoderm of the embryo but the muscles of the iris of the eye and myoepithelial cells of the salivary, mammar

What are biological troubles, What are the biological troubles that mollusc...

What are the biological troubles that molluscs face due to their soft body? Because molluscs have a soft body they are more fragile. They also have more complexity to support t

What are the functional divisions of the nervous system, What are the funct...

What are the functional divisions of the nervous system? Functionally the nervous system can be separated into the somatic nervous system and visceral nervous system. The so

Determine the appearance of a plant cell, Determine the appearance of a pla...

Determine the appearance of a plant cell when water is plentiful? When water is plentiful, the central vacuole expands. The other organelles are pushed against the plasma me

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