Two-kingdom classification, Biology

Two-Kingdom Classification

The history of taxonomy is as old as man himself. It may be traced back to prehistoric times because man had learnt to designate living organisms by specific names very early in his evolutionary history. Much before the advent of civilisation living things had been categorised into animals and plants. Hippocrates (460-370 BC), Aristotle (384-322 BC) and many others had tried to put some order into the chaos of the bewilderingly large number of different life forms. Aristotle appears to have been the first to attempt a logical system of classification. He classified animals on the basis of presence or absence of blood as Sanguineous (with blood) and Non-sanguineous (without blood). He believed that in evolution, life had been directed towards a perfect animal form, having blood (Table 1.6). He incorporated this idea which is a hierarchical system of classification In his book entitled 'Scala Naturae'. He also recognised two kingdoms in the living world i.e., Plantae and Animalia. The former included mainly immobile forms, while the latter embraced mobile forms. We also know that one of the major differences between the two is that the members of Kingdom Plantae are autotrophic and obtain their food mostly by photosynthetic means and those of Kingdom Animalia are heterotrophic and obtain their food by ingestion.

Table: Aristotle's 'Scale of life' or Scala Naturae.

1839_Two-Kingdom Classification.png


Kingdom Plantae was later divided by biologists into two subkingdoms,

  1. Thallophyta containing the phylum Algae (with chlorophyll) and Phylum Fungi (without chlorophyll) and
  2. Embryophyta with phylum Bryophyta (liverworts and mosses) and Phylum Tracheophyta (vascular plants).

Kingdom Animalia, on the other hand, was divided into Subkingdoms Protozoa containing unicellular forms and Sub Kingdom Metazoa including sponges and other multicellular organisms. A third Sub Kingdom Parazoa was later created and the sponges were shifted to this Sub Kingdom due to their intermediate position. between uni and multicellular organisms.

Posted Date: 1/12/2013 4:18:43 AM | Location : United States







Related Discussions:- Two-kingdom classification, Assignment Help, Ask Question on Two-kingdom classification, Get Answer, Expert's Help, Two-kingdom classification Discussions

Write discussion on Two-kingdom classification
Your posts are moderated
Related Questions
The crude oil obtained from earth's crust is refined by following steps. Step 1: separation of water Cottrell's process is used for separation of water. Crude oil is an emu

Q. From which germ layer do the epidermis and the nervous system originate? What are other organs and tissues made from that germ layer? Epidermis and nervous system have the s

Define Reagents Estimation of Iron in the Solution? 1. Conc. sulphuric acid (iron free) 2. Conc. potassium permanganate solution 3. Saturated potassium persulphate (K 2 S

Define the Etiology and Clinical Features of alzheimer's disease? The probable risk factors include a genetic basis, head injury, low education level, Down syndrome and mother

A substitution mutation occurs in the GRE making it unrecongnizable to the glucocorticoid receptor. What impact would this have on the transcription of the gene downstream of this

Explain Trifluridine  (Viroptic)  Trifluridine is a nucleoside analog active against herpes viruses, including acyclovir-resistant strains. Marketed in an ophthalmic preparatio

What is Imbibition The ability of colloids to pick up water and swell when they come in contact with water is called imbibition. Imbibition is usually accompanied by the evo

Spray-drying method Spray-drying is the common drying method in the production of ISP. The primary physical form of ISP in commerce, is that of fine powders. Structured form

What is the Echocardiogram ? When doubts persist whether a patient has CHD or not despite a thorough clinical exam and chest X-ray, ECG, and hyperoxia test, an echocardiogram s