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 ascending type of paper chromatography, Define ascending type of pap...

Define ascending type of paper chromatography? The ascending type consists in dipping the lower end of the paper containing the sample spots into the solvent so that it is abov

Whcih animals are triploblastic, Which one of the following kinds of animal...

Which one of the following kinds of animals are triploblastic? 1. Flat worms 2. Sponges 3. Ctenophores 4. Corals Flat worms

Explain about the sugaring - methods of food processing, Explain about the ...

Explain about the Sugaring - methods of food processing? Water is withdrawn from the microbial cells when they are placed in a strong sugar solution (about 68%) and thus result

Systems of classification plants, Q. Can you show the Systems of classifica...

Q. Can you show the Systems of classification plants? The development of angiosperm classification has been one of the most fascinating subject. A study of sequential events le

Define fluids requirement to avoid underweight problem, Define Fluids requi...

Define Fluids requirement to avoid underweight problem? Take fluids only after a meal instead of with or before meals so that food intake is not reduced. High calorie nourishin

What do you mean by hemoglobin f, Q. What is the hemoglobin F? Why does the...

Q. What is the hemoglobin F? Why does the fetus need different hemoglobin? Hemoglobin F is the hemoglobin found in the hemoglobin and mammalian fetus. A is the normal hemogl

Write a hypothesis and null hypothesis, Determine which of the following ob...

Determine which of the following observations (A-J) could lead to a testable hypothesis. For those that are testable: Write a hypothesis and null hypothesis What would be your expe

Explain the ethical decisions in nutrition care, Some of  the  situations  ...

Some of  the  situations  that  concern ethical decisions in nutrition care are as follows: Difficulty of adequate nutritional support of malnourished patients, a) A problem

How hyperventilation affect blood ph, Freediving is an activity in which a ...

Freediving is an activity in which a person dives, sometimes to great depth, without the use of scuba gear. The diver must hold his or her breath for the duration of the dive. (The

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