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NCERT Solutions for Class 11 Biology Chapter 1 : The Living World

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Access NCERT Solutions for Class 11 Biology Chapter 1 : The Living World

Page Number 15

Question 1

Why do we classify an organism ?

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Solution

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Organisms are classified into different groups in order to identify any specific organisms. Classification of organisms helps scientists to study them and undertake research on them. Classification also helps us in understanding each individual organisms and their differences and similarities with other organisms and it also helps us to understand the evolutionary process in a better way.

Question 2

Why are the classification systems changing every now and then?

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Millions of plants, animals, and microorganisms found on earth, have been identified by the scientists while many new species are still being discovered around the world. Therefore, to classify these newly discovered species, with new characters, new systems of classification have to be devised every now and then. This creates the requirement to change the existing systems of classification.

Question 3

What different criteria would you choose to classify people that you meet often?

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We can classify people on the basis of their education, profession, hobbies, native place, gender, etc. This helps us in understanding people better.

Question 4

What do we learn from identification of individuals and populations?

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Through the identification of individuals and populations; we can learn about the native place, mother tongue, costumes, food habit, religion, caste, etc.

This kind of identification makes easy categorization of them.

Question 5

Given below is the scientific name of Mango. Identify the correctly written name.

Mangifera Indica or Mangifera indica?

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Mangifera indica.

When typed, scientific names follows the rules of Bionomial nomenclature. That is, the genus name should start with capital letter and the species name should be completely in small letters. When typed, these should be in italics. If written, they should be underlined separately.

Question 6

Define a taxon. Give some examples of taxa at different hierarchical levels?

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A particular level of hierarchy in the classification of living beings is called as a taxon. A taxon is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit.

For example, the basic level of classification is species, followed by genus, family, order, class, phylum or division, in ascending order. The highest level of classification is known as a kingdom. So each of these categories can be called as a taxon.

Question 7

Identify the correct sequence of taxonomical category

Species

\to

order

\to

phylum

\to

kingdom

Genus

\to

species

\to

order

\to

kingdom

Genus

\to

species

\to

phylum

\to

order

Genus

\to

species

\to

kingdom

\to

phylum

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A taxonomic category is a rank or level in the hierarchical classification of organisms. There are seven obligate categories and some intermediate categories. The seven obligate categories include- kingdom, division or phylum, class, order, family, genus and species. The classification of organisms in a definite sequence of hierarchy category is called hierarchy of categories. The correct sequence of taxonomical category is as follows:

Species

\to

Genus

\to

Family

\to

Order

\to

Class

\to

Phylum

\to

Kingdom

So, correct option is (A).

Question 8

Try to collect all the currently accepted meanings for the word species. Discuss with your teacher the meaning of species in case of higher plants and animals on one hand, and bacteria on the other hand?

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Solution

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Explanation:

In biological terms, species is the basic unit of taxonomy.
A group of organisms with similar structural and functional characteristics that breed in nature only with each other and have a close common ancestry is called a species.
In case of higher plants and animals, one species is distinguished from the other on the basis of distinct morphological differences.
In case of bacteria, one species is distinguished from the other basis of shape.

Hence, the meaning of species in case of higher plants and animals, and bacteria are different.

Question 9

Define and understand the following terms:
(i) Phylum (ii) Class (iii) Family (iv) Order (v) Genus

Hard

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Explanation:

(i) Phylum- Phylum is a level of taxonomic rank that exists below the kingdom and above the class.

e.g. phylum chordata.

Equivalent of phylum is division in plant kingdom.

(ii) Class- A class is a taxonomic rank that exists below the phylum and above the order.

e.g. class mammalia, class aves.

(iii) Family- Family is a taxonomic rank in biological classification that exists below order and above genus.

e.g. family hominidae

(iv) Order- Order is a taxonomic rank that exists below class and above family. e.g. order primates.

(v) Genus- Genus is a taxonomic rank in the biological classification that exists below family and above species.

e.g. homo

Question 10

How is a key helpful in the identification and classification of an organism?

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Solution

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Explanation:

Key is a taxonomical aid that helps in the identification of plant and animal species. These keys are based on similarities and dissimilarities in characters, generally in a pair called a couplet.

Each statement in a taxonomic key is referred to as a lead. For categorizing each taxonomic rank, such as family, genus, species, etc., different keys are used. It is also useful in the identification of unknown organisms.

Keys are of two types - indented and bracketed keys. Indented key provides a sequence of choices between two or more statements while in bracketed key, a pair of contrasting characters is used.

(i) Indented key to identify different species of Rhododendron.

1. Leaves evergreen

2. leaves densely hairy below, orange or white hair; flower

appears to have separate petals Rhododendron groenlandicum

3. Hair absent on leaves, flower has five petals fused in a shallow

tube Rhododendron maximus

4. Leaves deciduous

5. pink flowers with two free petals and three fused petals Rhododendron canadense

6. white to pink flowers with all petals fused together

(ii) Bracketed key to identify different species of Rhododendron.

1. Leaves evergreen - 2

2. Leaves deciduous - 3

3. Leaves densely hairy below, orange or white hair; flower

appears to have separate petals Rhododendron groenlandicum

4. Hair absent on leaves, flower has five petals fused in shallow

tube Rhododendron maximus

5. Pink flowers with two free petals and three fused petals Rhododendron canadense

6. White to pink flowers with all petals fused together - 4

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NCERT Solutions for Class 11 Biology Chapter 1 : The Living World

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Frequently Asked Questions on NCERT Class 11 Biology Chapter 1 : The Living World

Q1. What are the benefits of referring to the NCERT Solutions for Class 11 Biology Chapter 1?

Answer: Toppr's NCERT Solutions for Class 11 Biology Chapter 1 provides all the solutions have been created with the new CBSE pattern in mind, ensuring that students have a thorough understanding of their exams. It goes over all major concepts in depth, allowing students to better understand the ideas. Chapter 1 Biology Class 11 Questions and Answers can help you get good grades in tests and properly prepare for all of the important concepts.

Q2. How will the Studies of NCERT Solutions for Class 11 Biology Chapter 1 Help Students?

Answer: The NCERT Solutions provide step by step solutions for the questions given in NCERT textbook as per CBSE Board guidelines and are also prepared according to the exam pattern. This chapter covers all the main topics of living world.

Q3. What are the Key Topics in NCERT Solutions Class 11 Biology Chapter 1?

Answer: NCERT Solutions Class 11 Biology Chapter 1 teaches what is living?, diversity in the living world, taxonomic categories, taxonomical aids. A few other topics discussed are the characteristics of a living being, the diversity in the living world etc.