Class 11 biology Chapters 1 Diversity in Living world
Welcome to the Class 11 biology Chapters 1 Diversity in Living world page! This chapter introduces you to the fascinating variety of life forms present on Earth. Understanding the vast diversity of organisms, their classification, and the principles of taxonomy is crucial for building a strong foundation in biology.
In this chapter, you will explore:
- The importance of classification and the various systems used to categorize organisms.
- The concept of biological diversity, including the identification and naming of species.
- Key concepts in taxonomy, such as the five-kingdom classification system.
- A deep dive into plant and animal kingdom characteristics.
Our NCERT solutions for this chapter break down each concept step-by-step, helping you understand the material thoroughly and perform well in your exams. Whether you are revising for tests or want a better grasp of the content, these solutions provide clear explanations for every exercise and topic in this chapter.
Topics Covered in Chapter 1: Diversity in Living World:
- Living World: Introduction to the concept of life and its diversity.
- Taxonomy and Systematics: Understanding classification and nomenclature.
- Five Kingdom Classification: Detailed look at the five kingdoms of life.
- The Kingdom Plantae: Characteristics and classification of plants.
- The Kingdom Animalia: Characteristics and classification of animals.
- Biodiversity and Conservation: Importance of biodiversity and conservation efforts.
Chapter 1
1. Why are living organisms classified?
Soln. Living organisms are classified because of the following reasons:
(i) Easy identification.
(ii)Study of organisms of other places.
(iii)Study of fossils
(iv)Grouping helps in study of all types of organisms while it is impossible to study individually all of them.
(v) Itbringsoutsimilaritiesanddissimilarities. They help in knowing relationships among different groups.
(vi)Evolution of various taxa can be known.
2. Why are the classification systems changing every now and then?
Soln. From very early days till now biologists use several characters for classification system. These are morphology, anatomy, cytology, physiology, ontogeny, phylogeny, reproduction, biochemistry, etc. But day by day biologists are learning something new about organisms from their fossil records and using” advanced study techniques such as molecular phylogeny, etc. So their point of view about classification keeps changing. Thus the system of classification is modified every now and then.
3. What different criteria would you choose to classify people that you meet often?
Soln. The various criteria that may be chosen to classify people whom we meet often include behaviour, geographical location, morphology, family members, relatives, friends etc.
4. What do we learn from identification of individuals and populations?
Soln. The knowledge of characteristic of an individual or its whole population helps in identification of similarities and dissimilarities among the individuals of same kind or between different types of organisms. It helps us to classify the organisms in various categories depending upon these similarities and dissimilarities.
5. Given below is the scientific name of mango. Identify the correctly written name.
Mangifera Indica Mangifera indica
Soln. The correctly written scientific name of mango is Mangifera indica.
6. Define a taxon. Give some example of taxa at different hierarchical levels.
Slon. A taxonomic unit in the biological system of classification of organism is called taxon (plural taxa). For example a phylum, order, family, genus or species represents taxon. It represents a rank. For example, all the insects form a taxon. Taxon of class category for birds is Aves and taxon of Phylum category for birds is Chordata. The degree of relationship and degree of similarity varies with the rank of the taxon. Individuals of a higher rank, say Order or Family, are less closely related than those of a lower rank, such as Genus or Species.
7. Can you identify the correct sequence of taxonomical categories?
(a) Species —> Order —> Phylum —> Kingdom
(b) Genus—) Species—> OrderKingdom
(c) Species —> Genus —>Order —> Phylum
Slon. The correct sequence of taxonomical categories is
(c) i.e., Species —>Genus —> Order —> Phylum.
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.
Slon. Species occupies a key position in classification. It is the lowest taxonomic category. It is a natural population of individuals or group of populations which resemble one another in all essential morphological and reproductive characters so that they are able to interbreed freely and produce fertile offsprings. Each species is also called genetically distinct and reproductively isolated natural population. Mayr (1964) has defined species as “a group of actually or potentially interbreeding populations that are reproductively isolated from other such groups”.
9. Define and understand the following terms:
(i) Phylum (ii) Class (iii) Family
(iv) Order (v) Genus
Slon. (i) Phylum – Phylum is a category higher than that of Class. The term Phylum is used for animals. A Phylum is formed of one or more classes, e.g., the Phylum Chordata of animals contains not only the class Mammalia but also Aves (birds), Reptilia (reptiles), Amphibia (amphibians), etc. In plants the term Division is used in place of Phylum.
(ii) Class – A Class is made of one or more related Orders. For example, the Class Dicotyledoneae of flowering plants contains all dicots which are grouped into several orders (e.g., Rosales, Sapindales, Ranales, etc.).
lO.How is a key helpful in the identification and classification of an organism?
Slon.‘Key is an artificial analytic device having a list of statements with dichotomic table of alternate characteristics. Taxonomic
11.Illustrate the taxonomical hierarchy with suitable examples of a plant and an animal.
Slon. The arrangement of various taxa in a hierarchical order is called taxonomic hierarchy. The hierarchy indicates the various levels of kinship. The number of similar characters of categories decreases from lowest rank to highest rank. The hierarchical system of classification was introduced by Linnaeus.
The hierarchy of major categories is:
Species —►Genus-►Family —► Order—► Class
Kingdom -4— Phylum or Division
Increasing specificity – ► Decreasing specificity
Classification of a plant (Wheat):
Kingdom – Plantae
Division – Angiospermae
Class – Monocotyledonae
Order – Poales
Family – Poaceae
Genus – Triticum
Species – aestivum
Classification of an animal (Housefly):
Kingdom – Animalia
Phylum – Chordata
Class – Insecta
Order – Diptera
Family – Muscidae
Genus – Musca
Species – domestica