NCERT Solutions Class 11 Biology Chapter 2 Biological Classification
NCERT Solutions Class 11 Biology Chapter 2 Biological Classification: National Council of Educational Research and Training Class 11 Biology Chapter 2 Solutions – Biological Classification. NCERT Solutions Class 11 Biology Chapter 2 PDF Download.
NCERT Solutions Class 11 Biology Chapter 2: Overview
Board |
NCERT |
Class |
11 |
Subject |
Biology |
Chapter |
2 |
Chapter Name |
Biological Classification |
Topic |
Exercise Solutions |
NCERT Solutions Class 11 Biology Chapter 2 Biological Classification
1.) Discuss how classification system has undergone several changes over a period of time?
Answer: – The system of classification had undergone tremendous changes over a period of time; there are various scientists who attempt to classify the living organisms. The first scientists who classify the living organism were a Greek philosopher Aristotle. The scientist provides 2 classifications. The first classification was for plants on the basis of height of plants. The plants are divided into 3 types such as herbs (Dwarf plants), Shrubs (Medium size), Plants and trees (Large sized plants). The second classification was done by Aristotle for the animals. The scientist divided the animals into 2 groups. The classification was based on the presence or absence of RBCs. He divided the animals into 2 groups. In the 1st group animals that contains RBC and 2nd group was animals who don’t have RBCs. Later on the scientist Linnaeous found some limitations in the classification of Aristotle. The Linnaeous classification was classified the organisms into 2 groups called Kingdom Plants and Animalia. But, the limitation of this classification could not place the fungus into any of kingdom, so the next classification was proposed by R.H. Whittaker, who classified the living organisms into 5 kingdoms such as a) Morera b) Protista c) Fungus d) Plantae e) Animalia.
2) State the economically important uses of a) Heterotrophic bacteria, b) Archebacteria.
Answer: –
a) Heterotrophic Bacteria:
- The heterotrophic bacteria are very useful to humans as with the help of these bacteria, human can degrade the complex organic material and can make fertilizers.
- The heterotrophic bacteria for e.g., Lactobacillus useful in production of curd.
b) Archebacteria:
- The Archebacteria are useful in various environmental processes such as bioremediation. This bioremediation means converting the toxic metals into nontoxic forms.
- The Archebacteria used to produce methane (with the help of bacteria Methanogen). This Methanogen is useful in paper and pulp industries and petroleum refineries. They are also involved in biogas production.
3) What is the nature of cell wall in Diatoms?
Answer: – Basically, diatoms can be defined as algae. The diatoms have cell wall in their structure which is transparent. The cell wall of diatoms is made up of silica. Therefore, cell wall of diatom is called asFrustule”. It is made up of 2 parts that is called as theca, such as epitheca and hypotheca.
4) Find out what do the terms ‘algal bloom’ and ‘red tides’ signify.
Answer: – The algal bloom can be termed as the excessive accumulation of algae in water bodies such as, marine water and fresh water. This tremendous increase in concentration of algae causes it to accumulate at the surface of water. This algal bloom completely spread at the surface of water, so that the water oxygen content decreases and due to less oxygen in water, the aquatic organism could not much oxygen for respiration and fish kill condition occurs in water.
Red tide is the term related with algal bloom. This excessive accumulation of algae causes to the release some toxins, this released toxins are harmful to aquatic organisms and humans also. This is called as Red tide.
5) How are viroids different from Viruses?
Answer: – The viroids differ from viruses.In terms of infection, the microorganism which is able to cause the infection in humans, animals and plants (in all living organisms) are called as viruses / virions.
Viruses |
Viroids |
i. The infectious organisms able to cause infection in all living organisms. | i. The small or tiny infectious particle causes infection only in plants. |
ii. The genetic material can be DNA or RNA. | ii. The genetic material mainly RNA |
iii. Presence of protein coat. | iii. Absence of protein coat. |
iv. E.g. influenza virus | iv. E.g. tobacco mosaic virus (TMV). |
6) Describe briefly four major groups of Protozoa?
Answer: -The protozoa can be defined as a single celled microorganism and eukaryotic that means contains true nucleus. The protozoa can be divided into four major such as,
- Amoeboid protozoa: They are single celled microorganism called as Amoeba. They are not rigid structure.According to need, they can change their shape. The amoeba present in fresh water and can move from one location to another with the help of specialized structure called pseudopodia.
- Ciliated Protozoa: They are present in river, pond and soil. They are differing from amoeboid protozoa on the basis of their locomotory organs. The ciliated protozoa contain cilia called as hair like projections. Cilia helpful as locomotary organ.
- Flagellated Protozoa: These are also unicellular microscopic organism, which having flagella as their locomotory organ.With the help of flagella, these protozoa can move from one location to another location. Therefore called as flagellated protozoa.
- Sporozoans: They are also called as Apicoplexa.They have apical complex structure. These sporozoans show gliding movement with the help of gliding, they can move from one location to another.
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7) Plants are autotrophic. Can you think of some plants that are partially heterotrophic?
Answer: – Yes, some plants are partially heterotrophs. Autotrophic plants are those plants which can prepare their own food with the help of photosynthesis by taking CO2 and H2O and makes the sugar. Whereas, the heterotrophic organism can take their food from decaying organic matter or depend on another living organisms. Some plants have evolved organs, so that they can grow on another plant for e.g. parasitic plants.
8) What do the term phycobiont and mycobiont. Signify?
Answer: –
a) Phycobiont: Phyco – Algae; biont – living organisms. Phycobiont can be defined as the algae, which is photosynthetic have ability to make their own food material. The algae provide food to fungus. It is the part of lichen.
b) Mycobiont: Myco – Fungus; biont – living organisms. The living organism which is heterotrophic; cannot prepare their own food. The fungus is part of lichen. This fungus provides shelter to algae. Therefore, the algae + fungus = Lichen. Lichen is mutualistic product of algae and fungus. Mutualism can be defined as the two organisms living together and beneficial to one another.
10) What are characteristic feature of Euglenosides?
Answer: –
- They also called as Euglena. They are single celled microscopic microorganism.
- The mode of nutrition can be autotrophic and heterotrophic.
- The organism has no cell wall but instead contains pellicle membrane.They can move by gliding mechanism.
11) Give a brief account of viruses with respect to their structure and nature of genetic material. Also name four common viral diseases.
Answer: -Viruses are microscopic organisms. They can infect almost all the living organisms such as plants, humans and animals. In the structure of viruses, a protein coat is present called capsid, which gives protection to virus and in this capsid, the genetic material is enclosed. The virus can be classified on the basis of their genetic material. The genetic material can be DNA or RNA. Some common examples of viruses are AIDS, Corona Virus, Polio Virus, Influenza etc.
12) Organize a discussion in your class on the topic – are viruses living or non-living?
Answer: -It is difficult to decide that viruses are living or non-living, but our discussion came to approximate conclusion that viruses can be living organisms. Viruses don’t have cellular organelles, they cannot respire. These are characteristics of non-living things but they have some living organism characters such as they can grow inside the host.
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