The Living World Class 11 Extra Questions and Answers Free PDF Download
FAQs on CBSE Important Questions for Class 11 Biology The Living World - 2025-26
1. What are the key defining characteristics of a living organism that are essential for the CBSE Class 11 Biology exams 2025-26?
For exam purposes, the key defining characteristics of living organisms are metabolism, cellular organisation, and consciousness. While growth and reproduction are also characteristics, they have exceptions (e.g., non-living things can grow, sterile organisms cannot reproduce). Therefore, for a definitive answer, focus on the following:
- Metabolism: The sum total of all chemical reactions occurring in the body.
- Cellular Organisation: All living organisms are composed of cells and their products.
- Consciousness: The ability to sense the surroundings and respond to external stimuli.
2. What is binomial nomenclature, and what are the universal rules that must be followed when writing a scientific name?
Binomial nomenclature is the system of providing a scientific name with two components, introduced by Carolus Linnaeus. It is a frequently asked question in exams. The universal rules are:
- Biological names are generally in Latin and written in italics.
- The first word represents the genus, while the second word denotes the specific epithet (species).
- When handwritten, both words are separately underlined.
- The genus name starts with a capital letter, while the species name starts with a small letter (e.g., Mangifera indica).
3. How are taxonomic aids like museums and zoological parks important for study as per the Class 11 syllabus?
Taxonomic aids are crucial tools for classification and identification. For exams, their importance can be summarised as:
- Museums: They have collections of preserved plant and animal specimens for study and reference. They are a repository of dead specimens, often preserved in jars with solutions or as dry specimens (insects in boxes, larger animals stuffed).
- Zoological Parks (Zoos): These are places where wild animals are kept in protected environments under human care. They allow us to study the behaviour, food habits, and life cycle of living animals in conditions similar to their natural habitats.
4. List the seven obligate taxonomic categories in their correct hierarchical sequence.
Understanding the taxonomic hierarchy is a fundamental and expected question. The correct ascending order of the seven obligate categories is: Species → Genus → Family → Order → Class → Phylum (for animals) / Division (for plants) → Kingdom.
5. Why is reproduction not considered a defining or all-inclusive characteristic of living organisms?
This is a higher-order thinking (HOTS) question. While reproduction is a fundamental characteristic of most living things, it is not a defining property because there are exceptions. Many living organisms are sterile and cannot reproduce. For example:
- Mules (a hybrid of a male donkey and a female horse) are sterile.
- Worker bees in a beehive are sterile females.
- Infertile human couples are living but do not reproduce.
Since there are living organisms that do not reproduce, it cannot be an all-inclusive defining characteristic of life.
6. How does a taxonomic key function as an analytical tool for identifying an unknown organism?
A taxonomic key is an analytical tool used for identifying organisms based on their similarities and dissimilarities. It works by presenting a series of contrasting, paired statements called a couplet. For each character, the user must choose one of the two options. Each choice leads to another couplet, and this process continues until the organism is identified. The statement that is accepted is called a lead. Since keys are analytical in nature and based on a series of choices, they are crucial for accurate classification.
7. Distinguish between the concepts of taxonomy and systematics. Which term holds a broader scope?
This is a common point of confusion and an important question for clarifying concepts:
- Taxonomy: This is the science of identification, classification, and nomenclature (naming) of organisms. Its primary focus is on classifying organisms into different taxa based on their observable characteristics.
- Systematics: This is a broader field that includes taxonomy but also studies the evolutionary relationships between organisms. It aims to understand the evolutionary history (phylogeny) and arranges organisms based on these relationships.
Therefore, systematics has a broader scope as it encompasses both taxonomy and phylogeny.
8. What is biodiversity, and why is its conservation a critical concern for our planet?
Biodiversity refers to the variety of life forms and ecosystems found on Earth. It encompasses the diversity within species (genetic diversity), between species (species diversity), and of ecosystems (ecosystem diversity). Conservation is critical because:
- It maintains ecological balance, such as pollination, nutrient cycling, and climate regulation.
- It provides essential resources for humans, including food, medicine, and industrial products.
- Losing biodiversity can lead to the collapse of ecosystems, affecting the entire food web and threatening human survival.
