Characteristics of the five-kingdom classification, Biology

Characteristics of the Five-Kingdom classification

At present, as you know, the trend is to follow the five-kingdom classification. However, while accepting the Five-Kingdom Classification, zoologists still treat Protozoa which comes under Kingdom Protista as the most primitive group of non chordates. This is partly because of historical reasons and partly because most zoologists are also interested in Protozoa. We have also followed the five kingdom of classification in our course. Table shows the characteristics of the five kingdoms proposed by Whittaker and followed by us in the Animal Diversity Course.

  • Monera

The earliest organisms to inhabit earth. They are microscopic, single celled prokaryotes. They lack true nuclei, but have only nuclear regions or nucleoids. The single chromosome is formed of one circular mo.lecule of DNA not associated with any proteins. They also lack membranous organelles like mitochondria, chloroplasts etc. Mitosis or meiosis in cell division does not occur. Cells divide by binary fission. Cell walls are composed usually of peptidoglycan (a substance derived from amino acids and sugars); many secrete a capsule made of polysaccharide material. There is now a tendency to split Kingdom Monera into t\ko separate kingdoms viz. Kingdom Archaebacteria (ancient bacteria) and kingdom Eubacteria (true bacteria).
Representatives: archaebacteria, blue-green algae, actinomycetes, fruiting,bacteria, rickettsias, mycoplasmas, Bdello vibrios etc.

  • Protista (Protoctista)

Protists are single celled eukaryotes; some form loose aggregations of cells called colonies. It is believed that the first eukaryotes were protists, some of which gave arise to higher eukaryotes - fungi, plants and animals that dominate the world today.
Representatives: protozoa and unicellular algae.

  • Fungi

Diverse group of multicellular eukaryotes; plant-like but cannot carry out photosynthesis due to absence of chlorophyll. They obtain food through their surface from a living or a nonliving organic source by absorption, instead of ingesting it as animals do. In many cases they secrete digestive enzymes outside their body which break down food. The breakdown products are absorbed across the fungal wall. During reproduction fungi may produce both asexual and sexual spores.
Representatives: slime moulds, moulds or true fungi, yeasts, mildew, rust, mushrooms.

  • Plantae

Multicellular, autotrophic eukaryotes with cell wall containing cellulose. All plants have reproductive tissues or organs and pass through distinct developmental stages and alternation of generations. Cells often have large central vacuole. Plants have indeterminate growth and often have no fixed body size nor exact shape.
Representatives: multicellular algae, mosses, horse tails, lycopods, ferns and seed plants.

  • Animalia

Multicellular eukaryotic heterotrophs. Animals lack photosynthetic pigments and obtain nutrients by ingesting other organisms. Cells lack cell wall. Many of the members exhibit advanced tissue differentiation and complex organ systems and move about freely; characterised by quick response to stimuli, with specialised nervous tissue for coordination. , Growth is determinate, mostly with definite size and shape.

Representatives,: sponges, jelly fishes, flat worms, round worms, segmented worms, molluscs, arthropods, echinoderms, chordates (fishes, amphibians, reptiles, birds, mammals).

You may have observed that the Five-Kingdom-Classification of Whittaker does not include the viruses. They should probably have their own kingdom since they arc unlike any other group of organisms. But kingdoms are supposed to reveal evolutionary relationships, and since the evolutionary origins of viruses are unknown, we cannot yet indicate their exact position. They are supposed to have originated after cellular organisms came into existence, because viruses depend upon the latter for their existence. So they are not the most primitive organisms from which cellular organisms have evolved.

Posted Date: 1/12/2013 4:43:07 AM | Location : United States







Related Discussions:- Characteristics of the five-kingdom classification, Assignment Help, Ask Question on Characteristics of the five-kingdom classification, Get Answer, Expert's Help, Characteristics of the five-kingdom classification Discussions

Write discussion on Characteristics of the five-kingdom classification
Your posts are moderated
Related Questions
Q. What is the relationship between environmental resistance and the population growth according to the biotic potential curve and the real population growth curve? The differe

Im learning about difference cell structures in science. I was wondering if I might be able to get some information about the epithelial tissue, and the connective tissue. Thankyou

Weight Measurement of New Born Check weight on an infant weighing machine. Weight of the neonate is 2.8-3.5 kg with an average weight of 2.5 kg. When taking weight take

How to Calculate the Requirements for the Calcium in Body? Requirements for calcium depend upon the rate at which calcium is incorporated into bone; they are therefore highest

Arteries - Circulation The arteries deliver blood from the heart. Figure shows the structure of arteries and the different layers of the vessel wall. The thick walls of these

SURGERY FOR CORONARY ARTERY DISEASE : Stenotic coronary artery disease (CAD) is caused by the thickening and narrowing of the coronary arteries (Atherosclerosis). Initially it cau

Name the Primary and secondary minerals found in soils Minerals such as silicate clays and iron oxide, which are formed by breakdown and weathering of less resistant materials,

If an infant had a cholesterol level of 800 you may suspect (blank)? How could this happen?d

Q. What is the function of the pupil and of the iris? The iris works like the diaphragm of a photographic camera since it has muscles that relax or contract varying the pupil d

Define the Features of Cladosporium? Identifying Features of Cladosporium: 1. Colonies are small, heaped, powdery and greenish black in colour. 2. Mycelium is septate and