CBSE Class 11 Biology NCERT Solutions Chapter 2 Biological classification 1. Discuss how classification systems have undergone several changes over a period of time? Ans.  The classification systems have undergone several changes with time. The first attempt of classification was made by Aristotle. He classified plants as herbs, shrubs, and trees. Animals, on the other hand, were classified on the basis of presence or absence of red blood cells. This system of classification failed to classify all the known organisms. Therefore, Linnaeus gave a two kingdom system of classification. It consists of kingdom Plantae and kingdom Animalia. However, this system did not differentiate between unicellular and multicellular organisms and between eukaryotes and prokaryotes. Therefore, there were large numbers of organisms that could not be classified under the two kingdoms. To solve these problems, a five kingdom system of classification was proposed by R.H Whittaker in 1969. On the bas...

  CBSE TEST PAPER-01 CLASS - XI BIOLOGY (Biological Classification) General Instruction: All questions are compulsory. Question No. 1 to 3 carry one marks each. Question No. 4 to 6 carry two marks each. Question No. 7 and 8 carry three marks each. Question No. 9 carry five marks. 1. Who introduced the five kingdom classification of organisms? 2. To which kingdom the multicellular decomposers belong? 3. Expand PPLO. 4. What is the basis of modern classification? 5. Give one example of a fungus as a soure of antibiotics? 6. How are viroids different from viruses? 7. Explain sexual reproduction in bacteria? 8. Discuss the salient features of viruses with the help of diagram? 9. Write the distinct characters of fungi & explain using a diagram. CBSE TEST PAPER-01 CLASS - XI BIOLOGY (Biological Classification) [ANSWERS] 1. R.H. Whittaker (1969) 2. Kingdom fungus. 3.Pleuro pneumonia like organisms. 4. Modern taxonomy is based on :- a) Evolutionary relationship. b) The similarities in ...

  CBSE Quick Revision Notes CBSE Class-11 Biology CHAPTER-03 PLANT KINGDOM Eukaryotic, multicellular, chlorophyll containing and having cell wall, are grouped under the kingdom Plantae. It is popularly known as plant kingdom. Phylogenetic  system of classification based on evolutionary relationship is presently used for classifying plants. Numerical Taxonomy  use computer by assigning code for each character and analyzing the features. Cytotaxonomy  is based on cytological information like chromosome number, structure and behaviour. Chemotaxonomy  uses chemical constituents of plants to resolve the confusion. Algae : These include the simplest plants which possess undifferentiated or  thallus like forms , reproductive organs single celled called gametangia. It includes only Algae. Characteristic of Algae Plant body is thallus, which may be unicellular, colonial, filamentous or parenchymatous. Usually aquatic but a few are also found in moist terrestrial hab...

  CBSE Class 11 Biology NCERT Solutions Chapter 3 Plant kingdom 1. What is the basis of classification of algae? Ans.  These divisions are based on the following factors: (a) Major photosynthetic pigments present (b) Form of stored food (c) Cell wall composition (d) Number of flagella and position of insertion Class I – Chlorophyceae Common name – Green algae Major pigments – Chlorophylls a and b Stored food – Starch Cell wall composition – Cellulose Flagella number and position – 28; equal and apical Class II – Phaeophyceae Common name– Brown algae Major pigments – Chlorophylls a and c, and fucoxanthin Stored food – Mannitol and laminarin Cell wall composition – Cellulose and algin Flagella number and position – 2; unequal and lateral Class III – Rhodophyceae Common name – Red algae Major pigments – Chlorophylls a and b, and phycoerythrin Stored food – Floridean starch Cell wall – Cellulose, pectin, and polysulphate esters Flagella number – Absent 2. When and where does reduc...