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

Bacterial cells, which intracellular organelles are present in bacteria?

which intracellular organelles are present in bacteria?

Gene constructs - transgenic animals, G e n e constructs Designing a...

G e n e constructs Designing and cloning of the gene construct is the fundamental step in the generation of transgenic animals, essentially determining success or failure of

Biotic balance of nature, Biotic Balance of Nature A nineteenth century...

Biotic Balance of Nature A nineteenth century Biologist is reported to have expressed, Glory of Britain is due to its old maids He reasoned Healthy Britons are nourished by roa

Discuss the health impact of any one specie, Discuss the economic/health im...

Discuss the economic/health impact of any one species of harmful water molds.

How depolarization of the neuronal plasma membrane generated, How is the de...

How is the depolarization of the neuronal plasma membrane generated? How does the cell return to its original rest? When the neuron receives a stimulus by the binding of neurot

What is difference in electrical charge between two points, The difference ...

The difference in electrical charge between two points: Select one: is called the potential difference between those points. is called the diffusion potential between those p

Skin, Two adaptation of the skin against attack by micro-organisms

Two adaptation of the skin against attack by micro-organisms

Nervous system - midbrain, MID BRAIN - Optics lobes 4 in number ( Corpo...

MID BRAIN - Optics lobes 4 in number ( Corpora Quadrizemmini ) in frog corpora bizemmini . Solid, optocoel is absent. 2 superior coculi and 2 inferior coculi are present.

Approaches to neuropsychological assessment, Approaches to Neuropsychologic...

Approaches to Neuropsychological Assessment Probably the most useful model of neuropsychological interpretation is described in Reitan and Wolfson's (1993) four approaches to a

Determine about the term - heterogeneous mixture, Determine about the term ...

Determine about the term - heterogeneous mixture The solid phase made up of soil and other source material for nutrients, is a heterogeneous mixture. Each nutrient source contr

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