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

What is an instance of a hypothesis, Q. What is an instance of a hypothesis...

Q. What is an instance of a hypothesis which may explicate why there is not a big representation of the class Reptilia found in Polar Regions? Beings of the class Reptilia are

Explain the chemical properties of milk, Explain the chemical properties of...

Explain the chemical properties of milk Autoclaving milk, wherein temperature of around 121 o C is achieved, causes browning. The brown colour is due to the heat effecting an i

Checker board (punnet''s square) method, CHECKER BOARD (PUNNET'S SQUARE) ME...

CHECKER BOARD (PUNNET'S SQUARE) METHOD 1.         If the genotypes of the parents are known, the genotypes of their offspring can be easily predicted with the help of a chart c

Define fluorides metabolism, Define fluorides Metabolism? Soluble fluor...

Define fluorides Metabolism? Soluble fluorides, even at high intake levels are almost completely absorbed from gastrointestinal tract. These include aqueous solutions of fluori

Use of protective eyewear as personal protective equipment, Q. Use of Prote...

Q. Use of Protective Eyewear as personal protective equipment? Protective lenses must be worn by dental personnel: 1. when performing procedures that can cause spatter or ae

Explain ground meristem in primary root growth, Explain Ground Meristem in ...

Explain Ground Meristem in Primary Root Growth? To review, the protoderm is the primary tissue that eventually forms the outside layer that covers the root and shoot and leaves

Is the bone marrow made of osseous tissue, Q. In which bones can bone marro...

Q. In which bones can bone marrow chiefly be found? Is the bone marrow made of osseous tissue? Bone marrow can mainly be found in the internal cavities of flat bones, like the

Mechanism of movement of chromosomes, The movement of the chromosome is cal...

The movement of the chromosome is called anaphase A, and the extension of the poles is termed anaphase B.The mechanism of these movements are discussed below. Chromosome move

Autoradiography, Autoradiography is the process to detect radioactively la...

Autoradiography is the process to detect radioactively labeled molecules (which commonly have been separated in an SDS-PAGE or agarose gel) based on their ability to develop an im

Complications of exchange transfusion, Complications of Exchange Transfusio...

Complications of Exchange Transfusion i) Infection of umbilical vessels and systemic injection related to blood transfusion like malaria, CMV, AIDS and hepatitis B. ii) O

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