Short & Long Question Answers with Solution: The Living World | Biology Class 11 - NEET PDF Download

Short Answer Type Questions

Q1. Why are living organisms classified?
Ans: The Earth is home to millions of organisms; some get instinct while others are discovered. Each organism has a local name based on where or who discovered them. So a proper standard classification is necessary to avoid confusion. Also, the standard classification helps in researching and studying the species.

Q2. Define the following:

1. Phylum
2. Class
3. Order
4. Genus

Ans:

1. Phylum: This classification level surpasses that of class and encompasses one or more interconnected classes sharing common traits.
2. Class: Positioned above the order level, this classification includes one or more interconnected orders with shared features.
3. Order: It comprises one or more connected families that share certain common characteristics.
4. Genus: This rank surpasses that of species and encompasses one or more closely related species.

Q3. Name two organisms that do not reproduce.
Ans: Organisms incapable of reproduction are referred to as sterile. Examples of such creatures include Mules and Worker Bees.

Q4. Linnaeus is considered the Father of Taxonomy. Name two other botanists known for their contribution to the field of plant taxonomy.
Ans: Carolus Linnaeus is credited as the father of taxonomy for pioneering species classification. Two additional botanists renowned for their contributions to plant taxonomy include G. Bentham and Joseph Dalton Hooker.

Q5. The number and kind of organisms are not constant. Explain.
Ans: The number and variety of organisms are not constant due to several factors:

• Mutation: Mutations are random genetic changes that can lead to the creation of new traits and characteristics. Over time, these mutations can accumulate, giving rise to new species or variations within existing ones.
• Sexual Reproduction: Sexual reproduction involves the combination of genetic material from two parents, resulting in offspring with unique genetic compositions. This diversity contributes to the constantly changing pool of organisms.
• Loss of Habitats: Changes in the environment, such as deforestation or urbanization, can lead to the destruction or fragmentation of habitats. This can force species to adapt, migrate, or, in some cases, become extinct.
• Environmental Threats: Natural events like wildfires, floods, and volcanic eruptions, as well as biological factors like diseases and competition, can influence the survival and distribution of organisms. These challenges can favor some species while affecting others.
• Anthropogenic Activities: Human activities, such as pollution, overexploitation of resources, introduction of invasive species, and climate change, have significant impacts on ecosystems and can lead to shifts in the populations and types of organisms present.

Q6. What do you mean by endemic and exotic species? Give examples for each.
Ans: 

• Exotic Species: Exotic species refer to living organisms residing in a location outside their native habitat. For example, Eichhornia crassipes is originally native to the Amazon basin but was introduced to India, making it an exotic species in India.
• Endemic Species: Endemic species are those found exclusively in a specific geographical area. For instance, Rauwolfia is an endemic species exclusively found within the borders of India.

Q7. Botanical gardens and zoological parks have:
(a) Collection of endemic living species only
(b) Collection of exotic living species only
(c) Collection of endemic and exotic living species
(d) Collection of only local plants and animals
Ans: (c)
Explanation: Biological gardens and zoological parks are formed to protect native and foreign species. That way, they collect and safeguard both endemic and exotic species.

Q8. The scientific name of the Mango is given below. Identify the written name correctly. 

• Mangifera Indica
• Mangifera indica

Ans: The accurate name for the mango is "Mangifera indica" because scientific names consist of two parts: the genus and the species. The initial part represents the genus, and the latter denotes the species. In this case, "Mangifera" is the genus name, and "indica" is the species name. It's a convention to capitalize the first letter of the genus and use lowercase for the species, so the correct name is "Mangifera indica."

Q9. What is taxon? Give a few examples.
Ans: A taxon is a categorization of organisms at various levels in the hierarchical classification system, based on shared characteristics. For example, all insects belong to the taxon called "Arthropoda." Taxa can encompass a range of levels, including kingdom, phylum, class, order, family, and genus.

Q10. A person living in a coma is considered living or dead?
Ans: A person in a coma is often described as in a state of "living death." This is because someone in a coma remains biologically alive but lacks consciousness and responsiveness for an extended period, usually exceeding six hours. In such cases, the individual is considered to be in a state of brain death.

Long Answer Type Questions

Q1. What is the definition of "living," and what are the key characteristics that define living organisms?
Ans: Living organisms are entities capable of growth, reproduction, cellular organization, and responsiveness to their environment. The defining characteristics of living organisms include:

• Growth: Living organisms have the capacity to increase in both size and number.
• Reproduction: They can produce offspring, which can occur through sexual or asexual means.
• Metabolism: Living organisms engage in metabolic processes, converting food into energy through chemical reactions.
• Cellular organization: Cells are the fundamental structural and functional units of life, and all living organisms are composed of one or more cells.

Q2. Regarding Brassica compestris Linn.

1. What is the common name of this plant?
2. What do the first two words in its scientific name signify?
3. Why are scientific names typically written in italics?
4. What does "Linn." represent in the name?

Ans:

• The common name of this plant is "Mustard."
• The first two words of the scientific name indicate the generic name (Brassica) and the species name (compestris).
• Scientific names are usually italicized to emphasize their distinctness and conformity to binomial nomenclature rules.
• "Linn." is an abbreviation for Linnaeus, the scientist who first identified and classified this plant.

Q3. How does a scientist approach the identification, naming, and classification of a newly discovered plant species?
Ans: Scientists follow a systematic process to identify, name, and classify a newly discovered plant species. This involves:

• Studying morphological and anatomical characteristics of the plant.
• Comparing these characteristics with existing scientific literature and known species.
• Determining the plant's systematic position within the taxonomic hierarchy.
• Naming the plant according to binomial nomenclature rules.

Q4. What is meant by "Reproduction"?
Ans: Reproduction is a fundamental biological process found in living organisms. In general terms, it refers to the ability of organisms to produce offspring that are similar to their parents. Reproduction can occur through two main methods: sexual reproduction, involving the fusion of gametes from two parents, and asexual reproduction, which typically involves the production of genetically identical offspring from a single parent.

Q5. Explain the binomial system of nomenclature, including its components and significance. Who is credited with proposing this system, and why is it considered the most widely accepted method for naming organisms?
Ans:  The binomial system of nomenclature is a structured method employed for naming and distinguishing different species of organisms. This system involves assigning a unique, two-part name to each species, comprising a genus name (or generic word) and a specific epithet (or word). Proposed by the renowned biologist Carolus Linnaeus, this system has become the standard for naming and cataloging living organisms.

In this system, the first word in the binomial name represents the genus to which the species belongs, while the second word identifies the specific species within that genus. For instance, in the binomial name "Homo sapiens," "Homo" represents the genus (including humans and their closest relatives), and "sapiens" signifies the specific species, which, in this case, is modern humans.

The binomial system of nomenclature is highly regarded and widely accepted due to several compelling reasons:

1. Universal Consistency: This system follows a universally consistent format, with the first letter of the genus name capitalized and the specific epithet in lowercase. It adheres to the rules outlined by the International Code of Botanical, Zoological, and Bacteriological Nomenclature, ensuring clarity and standardization in scientific communication.
2. Precision and Clarity: Binomial names are precise and concise, eliminating confusion or ambiguity about the identity of a species. They provide an unambiguous reference point for scientists across different regions and languages.
3. Ease of Identification: By encapsulating key taxonomic information in a single name, the binomial system simplifies the identification and classification of organisms. It offers a compact yet comprehensive way to refer to and study the diversity of life on Earth.
4. Historical Significance: The binomial system of nomenclature, introduced by Carolus Linnaeus in the 18th century, has a rich historical legacy and is deeply ingrained in scientific tradition. Its enduring use has contributed to the continuity of biological knowledge and research.

Q6. What do you mean by living? Explain the defining characteristics of living organisms.
Ans: Living entities are those capable of growth, reproduction, possessing a cellular structure, and demonstrating awareness of their environment. These fundamental traits distinguish living organisms:

• Growth: All living beings exhibit the capacity for growth, encompassing both an increase in size and the multiplication of cells.
• Reproduction: Living organisms share the essential property of giving rise to new individuals, a process that can take place through sexual or asexual means.
• Metabolism: Living entities engage in metabolic processes, which involve a series of chemical reactions responsible for converting food into energy, sustaining vital life functions.
• Cellular Organization: The fundamental structural and functional unit of life is the cell, which forms the basis for all living organisms, whether composed of a single cell or multiple cells.

Q7. What is the concept of metabolism, and how does it function in living organisms?
Ans: Metabolism is a fundamental concept in biology that encompasses a series of chemical reactions within living organisms to maintain life and sustain essential functions. It is a dynamic and continuous process that involves the conversion of various molecules, including carbohydrates, fats, and proteins, into energy and other necessary substances.
Metabolism serves several critical purposes:

• Energy Production: One of its primary functions is the extraction and release of energy from nutrient molecules. During digestion, carbohydrates, fats, and proteins are broken down into simpler molecules, such as glucose, fatty acids, and amino acids. These molecules are then further processed through metabolic pathways to generate adenosine triphosphate (ATP), the universal energy currency of cells.
• Anabolism: Metabolism encompasses two major components. Catabolism involves the breakdown of complex molecules into simpler ones, releasing energy in the process. In contrast, anabolism comprises the synthesis of complex molecules from simpler precursors, requiring energy input. Anabolic processes are crucial for growth, repair, and the formation of complex biological structures, such as proteins and nucleic acids.
• Regulation: Metabolism is tightly regulated to maintain a state of balance and homeostasis within an organism. Enzymes play a critical role in catalyzing metabolic reactions, ensuring they occur at the appropriate rates to meet the organism's energy and biosynthetic needs.
• Waste Elimination: Metabolism generates waste products, including carbon dioxide, water, and nitrogenous compounds like urea. These waste materials must be eliminated from the body to prevent toxicity and maintain internal stability.

Q8. What are the universal rules of nomenclature?
Ans: The five main rules of nomenclature are-

1. These names are derived from Latin, so these names should always be written in Italics. 
2. The biological world is composed of two components- genus and species. Genus represents the first word, while the second word represents the species epithet.
3. When written in hand or typed, the name should always be underlined and written or printed in Italics.
4. The first letter of the first word representing genus should always be in the capital, while the first letter of the species should always be small. E.g.- Panthera Tigris (tiger)
5. The author’s name is generally used at the end of the biological name. E.g.- Panthera Tigris (Linn). It indicates the name of the person that discovered the species.