NCERT Solutions: The Living World
Class 11 Biology — Chapter 1 Comprehensive Textbook Exercise Answers
CBSE / NCERT Class 11 Biology Premium Study Resource
Question 1: Why are living organisms classified?
Living organisms are classified for several fundamental scientific reasons:
• Vast Diversity: There are millions of distinct species of plants, animals, and microorganisms on
Earth. Classification structures this immense variety into manageable groups.
• Ease of Study: It is practically impossible to study every individual organism. Classifying
organisms into specific groups allows scientists to study a few representative organisms and infer
general characteristics about the whole group.
• Inter-relationships: It helps in understanding the relationships, shared features, and evolutionary
pathways (phylogeny) among different groups of organisms.
• Identification and Nomenclature: It provides a systematic framework to identify newly
discovered organisms and assign them a globally accepted scientific name.
Question 2: Why are the classification systems changing every now and then?
The classification systems change periodically due to the dynamic nature of biological science:
• Advancement in Technology: Early systems were based strictly on easily observable, superficial
morphology (shape, color, habitat). With advances in microscopy and molecular biology, scientists
can now analyze internal structures, cellular components, and genetic architecture.
• New Discoveries: As exploring remote environments continues, new species are constantly
discovered that do not fit neatly into existing classification structures, prompting revisions.
• Phylogenetic & Molecular Criteria: Modern taxonomy increasingly relies on evolutionary
relationships (phylogeny) and DNA/RNA sequencing rather than just physical features. For
instance, the system transitioned from the traditional Two-Kingdom model to R.H. Whittaker's
Five-Kingdom model, and subsequently to Three-Domain models based on molecular insights.
Class 11 Biology • Chapter 1 Solutions 1
, Question 3: What different criteria would you choose to classify people that you
meet often?
To classify people encountered on a day-to-day basis, various criteria can be applied depending on
the objective:
• Professional/Functional Relationship: Classifying them as family members, friends, teachers,
classmates, neighbors, or service providers.
• Age Group: Categorizing into children, teenagers, adults, and senior citizens.
• Gender: Categorizing into male, female, or non-binary.
• Geographical Location / Residence: Sorting by those living in the immediate neighborhood,
native city, or different regions.
• Shared Interests/Habits: Grouping based on hobbies, such as sports enthusiasts, readers,
musicians, or colleagues.
Question 4: What do we learn from identification of individuals and populations?
The identification of individual organisms and whole populations yields essential biological insights:
• Distinct Traits: It provides knowledge regarding the distinctive morphological, anatomical, and
physiological characteristics unique to a species.
• Intraspecific Variation: It highlights the degree of variance, similarities, and differences present
among members of the same population (intraspecific diversity).
• Ecological Niches: It helps scientists understand the specific habitats, geographic distribution,
and roles that populations play within an ecosystem.
• Conservation and Management: Identifying population dynamics, sizes, and threats allows
conservationists to implement effective strategies to prevent the extinction of endangered
species.
Class 11 Biology • Chapter 1 Solutions 2
Class 11 Biology — Chapter 1 Comprehensive Textbook Exercise Answers
CBSE / NCERT Class 11 Biology Premium Study Resource
Question 1: Why are living organisms classified?
Living organisms are classified for several fundamental scientific reasons:
• Vast Diversity: There are millions of distinct species of plants, animals, and microorganisms on
Earth. Classification structures this immense variety into manageable groups.
• Ease of Study: It is practically impossible to study every individual organism. Classifying
organisms into specific groups allows scientists to study a few representative organisms and infer
general characteristics about the whole group.
• Inter-relationships: It helps in understanding the relationships, shared features, and evolutionary
pathways (phylogeny) among different groups of organisms.
• Identification and Nomenclature: It provides a systematic framework to identify newly
discovered organisms and assign them a globally accepted scientific name.
Question 2: Why are the classification systems changing every now and then?
The classification systems change periodically due to the dynamic nature of biological science:
• Advancement in Technology: Early systems were based strictly on easily observable, superficial
morphology (shape, color, habitat). With advances in microscopy and molecular biology, scientists
can now analyze internal structures, cellular components, and genetic architecture.
• New Discoveries: As exploring remote environments continues, new species are constantly
discovered that do not fit neatly into existing classification structures, prompting revisions.
• Phylogenetic & Molecular Criteria: Modern taxonomy increasingly relies on evolutionary
relationships (phylogeny) and DNA/RNA sequencing rather than just physical features. For
instance, the system transitioned from the traditional Two-Kingdom model to R.H. Whittaker's
Five-Kingdom model, and subsequently to Three-Domain models based on molecular insights.
Class 11 Biology • Chapter 1 Solutions 1
, Question 3: What different criteria would you choose to classify people that you
meet often?
To classify people encountered on a day-to-day basis, various criteria can be applied depending on
the objective:
• Professional/Functional Relationship: Classifying them as family members, friends, teachers,
classmates, neighbors, or service providers.
• Age Group: Categorizing into children, teenagers, adults, and senior citizens.
• Gender: Categorizing into male, female, or non-binary.
• Geographical Location / Residence: Sorting by those living in the immediate neighborhood,
native city, or different regions.
• Shared Interests/Habits: Grouping based on hobbies, such as sports enthusiasts, readers,
musicians, or colleagues.
Question 4: What do we learn from identification of individuals and populations?
The identification of individual organisms and whole populations yields essential biological insights:
• Distinct Traits: It provides knowledge regarding the distinctive morphological, anatomical, and
physiological characteristics unique to a species.
• Intraspecific Variation: It highlights the degree of variance, similarities, and differences present
among members of the same population (intraspecific diversity).
• Ecological Niches: It helps scientists understand the specific habitats, geographic distribution,
and roles that populations play within an ecosystem.
• Conservation and Management: Identifying population dynamics, sizes, and threats allows
conservationists to implement effective strategies to prevent the extinction of endangered
species.
Class 11 Biology • Chapter 1 Solutions 2
