NCERT Class 11-Biology: Chapter – 1 the Living World Part 5 (For CBSE, ICSE, IAS, NET, NRA 2023)

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Question 4:

What are taxonomical aids? Give the importance of herbaria and museums. How are Botanical gardens and Zoological parks useful in conserving biodiversity?


The taxonomic aids are the aids which help in identification, classification and naming of a newly discovered organisms (plant or animal) .

It could be in the form of preserved document like herbaria or specimen kept at museums or scientific institutions. Other aids can be in the form of written document like monograph, taxonomic keys, couplets, etc. A new organism found can be studied while comparing it with living plants and animals living in protected areas like Botanical gardens, Zoological parks, etc.

Boranical gardens helps in conservation of plants by

(i) Growing important local plant species and keeping record of them.

(ii) Growing and maintaining rare and endangered species.

(iii) Supplying seeds for different aspects of botanical research.

Whereas zoological parks also contribute in conserving biodiversity by

(i) Providing natural environment and open space to animals, i.e.. , wild life species.

(ii) Keeping them safe from their predators ensuring protection, food and shelter.

(iii) Providing home to different native and exotic wild anials.

(iv) Involving in the rescue of endangered species.

(v) Facilitating breeding of animals and releasing them free.

Thus, both botanical gardens and zoological parks play an important role in conservation of biodiversity.

Question 5:

Define a tax on. What is meant by taxonomic hierarchy? Give a flow diagram from the lowest to highest category for a plant and an animal. What happens to the number of individuals and number of shared characters as we go up the taxonomical hierarchy?


There are 7 major categories, namely the kingdom, phylum class, order, family, genus and species. The sequence can be remembered by memorizing the sentence as a pneumonic. ‘Keep sports clean family gets sick’ .

Chep-1-Question 5-Flow Chart of Plant Categories

When we go up the taxonomic hierarchy, the number of common characters becomes lesser and lesser. For example; all members of a species will have the maximum number of common characters. On the other hand, all members of a genus will have a lesser number of common characters.

The number of individuals increases as we go up the taxonomical hierarchy.

Question 6:

A student of taxonomy was puzzled when told by his professor to look for a key to identify a plant. He went to his friend to clarify what ‘Key’ the professor was referring to? What would the friend explain to him?


Identification of a plant is a scientific process. One has to study the general morphological characters along with its habitat, place of collection, time of flowering, etc. ,

for identification. Several reference materials are available in the form of taxonomic keys. Professor meant to refer to these keys to help the student to identify the plant.

This concept of key was introduced by Ray. Separate taxonomic keys are required for each taxonomic category. keys are analytical in nature and are used as reference to help in identification of a newly discovered plant.

Question 7:

Metabolism is a defining feature of all living organisms without exception. Isolated metabolic reactions in vitro are not living things but surely living reactions Comment.


Metabolism is the sum of all synthesing (anabolic) and breaking down (catabolic) reactions. These are highly specific and enzymatically controlled reactions, which take place inside all the individual cells of unicellular or multicellular organisms. These are infact the basis of life. These reactions help organism to grow, reproduce, maintain their steady state and respond to stimuli. It can be understood by taking example of digestion.

All organisms need nutrition in the form of food, which is digested by metabolic reactions either intracellularly or extracellularly depending upon the type of organisms. So, all reactions which help the organisms to breakdown food molecules and then assimilate them for their growth and reproduction are metabolic reactions. Few reactions may be performed outside the cells, under controlled conditions; Chemical reactions usually involve specific set of conditions to take place. All biological reactions are highly specific, selective and are enzyme catalysed.