Class 11 (XI) Biology Chapter 1 Living World NCERT Solutions
1. Why are living organisms classified?
Answer: Living organisms are classified to make their study and identification easier. Classification helps us to understand the relationships between different organisms and how they are related to each other. It also helps us to group organisms based on their characteristics and identify similarities and differences among them.
2. Why are the classification systems changing every now and then?
Answer: The classification systems are changing every now and then because new discoveries and advancements in scientific knowledge can change our understanding of the relationships between organisms. As a result, new categories or subcategories may need to be created or existing categories may need to be revised to reflect this new knowledge.
Chapter 1 : The Living World (Notes)
3.What different criteria would you choose to classify people that you meet often?
Answer: The criteria to classify people can vary depending on the purpose of the classification. For example, one could classify people based on their age, gender, occupation, education level, interests, and many other factors.
4. What do we learn from identification of individuals and populations?
Answer: Identification of individuals and populations can provide information about the diversity and distribution of different species in a particular region. This information can help in the conservation and management of these species and their habitats.
5. Given below is the scientific name of Mango. Identify the correctly written name. Mangifera Indica Mangifera indica
Answer: The correctly written scientific name of Mango is Mangifera indica.
Chapter 1 : The Living World (Notes)
6. Define a taxon. Give some examples of taxa at different hierarchical levels.
Answer: A taxon is a group of organisms that are classified together based on their shared characteristics. Examples of taxa at different hierarchical levels include species (e.g., Homo sapiens), genus (e.g., Canis), family (e.g., Felidae), order (e.g., Carnivora), class (e.g., Mammalia), and phylum (e.g., Chordata).
7. Can you identify the correct sequence of taxonomical categories?
(a) Species Order Phylum Kingdom
(b) Genus Species Order Kingdom
(c) Species Genus Order Phylum
Answer: The correct sequence of taxonomical categories is (a) Species Order Phylum Kingdom.
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.
Answer: The currently accepted meanings of the word ‘species’ include:
- A group of organisms that can interbreed and produce viable offspring
- A group of organisms that share common characteristics and can be distinguished from other groups
- The basic unit of classification in biology
In the case of higher plants and animals, the concept of species is generally based on the ability to interbreed and produce viable offspring. However, in the case of bacteria, the concept of species is more complex and is based on genetic and biochemical differences.
9. Define and understand the following terms:
(i) Phylum – A taxonomic rank used to group organisms that share a set of characteristics, typically related to body structure and organization. For example, the phylum Chordata includes all animals that have a notochord or a backbone, including humans, dogs, and birds.
(ii) Class – A taxonomic rank used to group organisms that share a set of characteristics that are more specific than those used to define phyla. For example, the class Mammalia includes all animals that have hair or fur, mammary glands, and three middle ear bones, including humans, dogs, and bats.
(iii) Family – A taxonomic rank used to group organisms that share a set of characteristics that are more specific than those used to define classes. For example, the family Canidae includes all animals that are commonly known as canids or dogs, including wolves, foxes, and domestic dogs.
(iv) Order – A taxonomic rank used to group organisms that share a set of characteristics that are more specific than those used to define families. For example, the order Carnivora includes all animals that are commonly known as carnivores, including cats, dogs, bears, and weasels.
(v) Genus – A taxonomic rank used to group organisms that are closely related. For example, the genus Canis includes all species of dog-like carnivores, including wolves, coyotes, and domestic dogs.
10. Illustrate the taxonomical hierarchy with suitable examples of a plant and an animal.
Answer : Two examples of taxonomical hierarchies for a plant and an animal:
Plant Example: Mango
Kingdom: Plantae Phylum: Magnoliophyta Class: Magnoliopsida Order: Sapindales Family: Anacardiaceae Genus: Mangifera Species: Mangifera indica
Animal Example: Lion
Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Carnivora Family: Felidae Genus: Panthera Species: Panthera leo
In both examples, the taxonomical hierarchy begins with a broad category (Kingdom) and becomes more specific as you move down the list of categories. At each level of the hierarchy, organisms are grouped based on shared characteristics.