30 free MCQs on The Living World with worked answers and explanations. Biodiversity, taxonomy, binomial nomenclature, the taxonomic hierarchy, and taxonomic aids like herbaria and botanical gardens. The foundational first chapter of NCERT Biology.
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The taxonomic hierarchy narrows from Kingdom (broadest, covering the most organisms but fewest shared traits) down to Species (narrowest, fewest organisms but most shared traits) — every level in between is a progressively more specific subset of the one above it.
Q1.
Who proposed the system of binomial nomenclature?
Answer: B. Carolus Linnaeus
Why: Carolus Linnaeus introduced binomial nomenclature, giving every species a two-part Latinised name (Genus + species).
Q2.
In binomial nomenclature, the genus name always:
Answer: B. Starts with a capital letter
Why: The genus name starts with a capital letter and comes first; the species name is lowercase and comes second, e.g. Mangifera indica.
Q3.
The basic, lowest taxonomic category is:
Answer: C. Species
Why: Species is the basic taxonomic unit: a group of individuals similar enough to interbreed and produce fertile offspring.
Q4.
A herbarium is a collection of:
Answer: B. Dried and pressed plant specimens
Why: A herbarium stores dried, pressed plant specimens on labelled sheets, used for reference and identification.
Q5.
Botanical gardens are primarily used to maintain:
Answer: B. Living plant collections
Why: Botanical gardens maintain collections of living plants for reference, research, and conservation, unlike a herbarium which stores dried specimens.
Q6.
The correct order of taxonomic hierarchy, from broadest to narrowest, is:
Answer: B. Kingdom → Phylum → Class → Order → Family → Genus → Species
Why: The standard taxonomic hierarchy runs Kingdom → Phylum (or Division for plants) → Class → Order → Family → Genus → Species.
Q7.
A taxonomic key is mainly used for:
Answer: B. Identification of organisms based on contrasting characters
Why: A key helps identify organisms by presenting paired contrasting characters (couplets) that the user chooses between step by step.
Q8.
In the scientific name Homo sapiens, the word 'sapiens' represents the:
Answer: C. Species name
Why: In binomial nomenclature, the second word (here, sapiens) is the species name, written in lowercase after the capitalised genus name, Homo.
Q9.
A collection of dead, dried and preserved plant specimens mounted on sheets for reference is called a:
Answer: A. Herbarium
Why: A herbarium is a store of dried, pressed plant specimens mounted on sheets along with a label giving date and place of collection, used as a taxonomic reference.
Q10.
A group of related families is grouped together under a single:
Answer: B. Order
Why: In taxonomic hierarchy, related families are grouped into an Order, which is itself grouped with other related orders into a Class.
Q11.
In the scientific name Mangifera indica, which part is the genus?
Answer: B. Mangifera
Why: Mangifera is the genus (capitalised, written first); indica is the species (lowercase, written second).
Q12.
Systematics differs from taxonomy mainly because systematics also includes:
Answer: B. Study of evolutionary relationships among organisms
Why: Taxonomy covers identification, naming, and classification; systematics is broader, also incorporating the study of evolutionary relationships (phylogeny) among taxa.
Q13.
A Flora, as a taxonomic aid, contains:
Answer: B. Actual information for identifying plants found in a given area
Why: A Flora provides detailed, actual information useful for identifying the plant species present in a particular geographic area.
Q14.
As classification moves from the Kingdom level down to the Species level, the number of:
Answer: B. Shared characteristics increases and organisms covered decreases
Why: Moving from Kingdom to Species, each level becomes more specific: shared characteristics among included organisms increase, while the number of organisms covered decreases.
Q15.
A 'Manual', as a taxonomic aid, is most useful for:
Answer: C. Identifying and classifying species found within a particular region
Why: A manual gives useful information for identifying names of species found in a particular area, helping in their classification and study.
Q16.
A zoological park primarily serves the purpose of:
Answer: D. Maintaining live wild animals for study and conservation
Why: Zoological parks (zoos) maintain live animals in a safe, protected environment, allowing the public to see them and researchers to study their biology and behaviour.
Q17.
Taxonomic hierarchy refers to the arrangement of categories such as kingdom, phylum and class because:
Answer: C. Each rank fits into an overall scheme reflecting evolutionary relatedness
Why: Taxonomic hierarchy is the step-wise arrangement of categories (kingdom to species) where each rank reflects a level of relatedness, with broader categories containing more diverse organisms than narrower ones.
Q18.
Why must the scientific name of an organism be written in italics (or underlined when handwritten)?
Answer: C. To mark it as a universal, standardised name distinct from common names
Why: Following the binomial nomenclature convention, scientific names are written in Latin and italicised (or underlined) to set them apart as formal, universally recognised names distinct from local common names.
Q19.
Among the taxonomic categories Phylum and Class, which one represents a broader, more inclusive group?
Answer: D. Phylum, since it includes several classes
Why: In the taxonomic hierarchy, Phylum is a broader category that may include several Classes, which in turn include several Orders, reflecting decreasing inclusiveness down the hierarchy.
Q20.
A 'population' that taxonomists may study to define a species typically refers to:
Answer: B. Interbreeding individuals more similar to each other than to other groups
Why: A species is often defined as a population of individuals with similar characters that can interbreed among themselves and produce fertile offspring, sharing greater resemblance to each other than to other populations.
Q21.
Two organisms are placed in the same Family but different Genera. What can be concluded about their relationship?
Answer: B. They share fewer characteristics than two organisms in the same Genus, but more than two organisms only sharing the same Order
Why: As taxonomic rank broadens (Species to Genus to Family to Order), shared characteristics decrease. Same-Family-different-Genus organisms share fewer traits than same-Genus organisms, but more than organisms only sharing a broader rank like Order.
Q22.
Why is a dichotomous key structured as a series of paired contrasting choices (couplets) rather than a single descriptive list?
Answer: B. Each couplet forces a binary decision based on one contrasting character, progressively narrowing down the identification until a unique answer is reached
Why: Each couplet presents two mutually exclusive, contrasting character choices; selecting one at each step systematically narrows the possibilities, leading step-by-step to a specific identification rather than requiring the user to compare against an undifferentiated full description.
Q23.
Why are viruses generally excluded from the five-kingdom classification system?
Answer: C. They lack a true cellular structure and replicate using host cell machinery
Why: Viruses are acellular, having no independent metabolism or cell structure; they replicate only by using a host cell's machinery, so they sit outside conventional kingdom classification.
Q24.
When a new species is found to fit none of the existing genera in a family, taxonomists usually respond by:
Answer: B. Erecting a new genus after comparing its characters with related taxa
Why: Taxonomy is a dynamic process: when a species does not fit known genera after careful comparison of shared and distinguishing characters, a new genus may be described to accommodate it.
Q25.
Two species are described as 'sister species' in a phylogenetic sense when they:
Answer: D. Share a more recent common ancestor with each other than with any other species
Why: Sister species share an immediate common ancestor exclusive of other species, making them each other's closest relatives on a phylogenetic tree.
Q26.
A key difference between a museum collection and a herbarium as taxonomic aids is that:
Answer: C. A herbarium stores dried, pressed plants; a museum holds broader preserved samples
Why: A herbarium is a specific repository for dried, pressed plant specimens mounted on sheets with collection data, whereas museums hold a wider range of preserved plant and animal specimens, including skeletons and pickled samples.
Q27.
Why does identification using a dichotomous key sometimes give an unreliable result for a damaged or incomplete specimen?
Answer: A. Each couplet relies on one contrasting feature, so a missing structure misleads that step
Why: Since each couplet in a dichotomous key depends on observing a particular contrasting character, a damaged specimen lacking that structure can lead the user down the wrong branch.
Q28.
How does the concept of a 'species' for sexually reproducing organisms generally differ from its application to organisms that reproduce mainly asexually?
Answer: D. Sexual species rely on interbreeding, asexual ones on morphological and genetic similarity
Why: The biological species concept (interbreeding populations producing fertile offspring) works well for sexual organisms but cannot apply to strictly asexual ones, which taxonomists instead group using morphological and genetic similarity.
Q29.
Why is a polynomial (descriptive, multi-word) naming system considered less practical than the binomial system for modern taxonomy?
Answer: D. Polynomial names grew long and inconsistent as more species were described
Why: Before Linnaeus, species were named with long descriptive Latin phrases that grew unwieldy as more species were discovered; the two-part binomial system standardised and simplified naming.
Q30.
Which statement best explains why metabolism, though common to all living organisms, is not by itself a sufficient criterion to distinguish living from non-living matter?
Answer: B. Isolated metabolic reactions in cell-free extracts are not considered alive
Why: Cell-free systems can perform many individual biochemical reactions in a test tube, but such isolated reactions occurring outside the body are not considered an indicator of life on their own.