Introduction: Diversity in the living world MCQs With Answer is an essential review for B. Pharm students preparing for pharmacognosy, microbiology and drug discovery exams. This concise guide covers biodiversity, classification, taxonomy, phylogeny, microbial diversity, plant and animal groups, and molecular tools such as 16S rRNA and DNA barcoding relevant to pharmaceutical studies. Understanding species concepts, evolutionary relationships and microbial variation helps pharmacists in drug sourcing, quality control and combating antimicrobial resistance. Practice-oriented MCQs improve identification skills, conservation awareness and application of taxonomy in pharmacology. Now let’s test your knowledge with 50 MCQs on this topic.
Q1. What is the highest taxonomic rank in the modern three-domain system?
- Kingdom
- Phylum
- Domain
- Class
Correct Answer: Domain
Q2. Which molecular marker is most commonly used for bacterial identification and phylogeny?
- COI gene
- 16S rRNA gene
- ITS region
- 18S rRNA gene
Correct Answer: 16S rRNA gene
Q3. Binomial nomenclature provides each species with which two names?
- Family and genus
- Genus and species
- Order and family
- Species and subspecies
Correct Answer: Genus and species
Q4. Which kingdom contains multicellular, photosynthetic organisms with cell walls of cellulose important in pharmacognosy?
- Fungi
- Animalia
- Plantae
- Protista
Correct Answer: Plantae
Q5. Which concept defines species as groups of interbreeding natural populations reproductively isolated from others?
- Morphological species concept
- Biological species concept
- Phylogenetic species concept
- Ecological species concept
Correct Answer: Biological species concept
Q6. Which of the following is NOT a criterion used in cladistics to infer evolutionary relationships?
- Shared derived characters (synapomorphies)
- Monophyly
- Overall similarity regardless of homology
- Parsimony
Correct Answer: Overall similarity regardless of homology
Q7. Which taxonomic rank comes directly above genus?
- Order
- Family
- Class
- Species
Correct Answer: Family
Q8. Which diversity index measures both species richness and evenness and is frequently used in ecological studies?
- Simpson’s index
- Shannon index
- Species-area curve
- Alpha diversity only
Correct Answer: Shannon index
Q9. Which domain includes organisms with unique membrane lipids and often extremophilic lifestyles?
- Bacteria
- Archaea
- Eukarya
- Prokarya
Correct Answer: Archaea
Q10. Which structure is characteristic of Gram-negative bacteria and contributes to endotoxin activity?
- Thick peptidoglycan layer
- Outer membrane containing lipopolysaccharide (LPS)
- Teichoic acids
- Endospore coat
Correct Answer: Outer membrane containing lipopolysaccharide (LPS)
Q11. DNA barcoding for animals commonly uses which mitochondrial gene?
- 16S rRNA
- COI (cytochrome c oxidase I)
- rbcL
- ITS
Correct Answer: COI (cytochrome c oxidase I)
Q12. Which group of organisms is acellular and requires a host cell to replicate?
- Bacteria
- Fungi
- Viruses
- Protozoa
Correct Answer: Viruses
Q13. Horizontal gene transfer in bacteria contributes primarily to which phenomenon relevant to pharmacy?
- Increased photosynthesis
- Antibiotic resistance spread
- Sexual reproduction
- Reduced mutation rates
Correct Answer: Antibiotic resistance spread
Q14. Which fungal feature is most important for classification at phylum level?
- Type of spore-producing structure (e.g., asci vs basidia)
- Cellulose cell wall composition
- Presence of chlorophyll
- Motility by flagella
Correct Answer: Type of spore-producing structure (e.g., asci vs basidia)
Q15. In plant taxonomy, which code governs the naming of algae, fungi and plants?
- International Code of Zoological Nomenclature (ICZN)
- International Code of Nomenclature for algae, fungi, and plants (ICN)
- International Code of Bacterial Nomenclature (ICBN)
- Geneva Code
Correct Answer: International Code of Nomenclature for algae, fungi, and plants (ICN)
Q16. Metagenomics is most useful for studying which type of diversity?
- Only cultured microorganisms
- Community-level genetic diversity including unculturable microbes
- Macroscale plant diversity in forests
- Animal behavioral diversity
Correct Answer: Community-level genetic diversity including unculturable microbes
Q17. Which term describes a group containing a common ancestor and all its descendants?
- Paraphyletic group
- Polyphyletic group
- Monophyletic clade
- Artificial group
Correct Answer: Monophyletic clade
Q18. Which organism group is a primary source of many antibiotics used in pharmacy?
- Algae
- Actinobacteria (e.g., Streptomyces)
- Protozoa
- Viruses
Correct Answer: Actinobacteria (e.g., Streptomyces)
Q19. Which of the following best describes convergent evolution?
- Shared ancestry causing similarity
- Independent evolution of similar traits in unrelated lineages
- Speciation due to geographic isolation
- Hybridization between species
Correct Answer: Independent evolution of similar traits in unrelated lineages
Q20. Which genetic marker is commonly used for fungal identification at species level?
- 16S rRNA
- ITS (Internal Transcribed Spacer)
- COI gene
- rbcL gene
Correct Answer: ITS (Internal Transcribed Spacer)
Q21. Which one of these is NOT a domain in the three-domain classification?
- Bacteria
- Fungi
- Archaea
- Eukarya
Correct Answer: Fungi
Q22. Adaptive radiation is best defined as:
- Gradual extinction of species
- Rapid diversification from a common ancestor into many forms
- Horizontal gene transfer among bacteria
- Stabilizing selection preventing change
Correct Answer: Rapid diversification from a common ancestor into many forms
Q23. Which cell structure is absent in prokaryotes but present in eukaryotes?
- Ribosomes
- Nucleus bounded by nuclear membrane
- Cell membrane
- DNA
Correct Answer: Nucleus bounded by nuclear membrane
Q24. Which classification method relies primarily on overall morphological similarity and can be misleading due to convergent traits?
- Phylogenetic systematics (cladistics)
- Molecular taxonomy
- Phenetic classification
- Genomic sequencing
Correct Answer: Phenetic classification
Q25. Which statement about viruses is true and relevant to vaccine design?
- All viruses have double-stranded DNA genomes
- Antigenic variation in viral surface proteins affects vaccine efficacy
- Viruses are unaffected by host immune responses
- Viruses synthesize their own ribosomes
Correct Answer: Antigenic variation in viral surface proteins affects vaccine efficacy
Q26. Which category in IUCN Red List indicates highest immediate risk of extinction?
- Least Concern
- Vulnerable
- Endangered
- Critically Endangered
Correct Answer: Critically Endangered
Q27. Which process increases genetic diversity in sexually reproducing populations?
- Binary fission
- Meiosis with recombination
- Asexual budding
- Clonal propagation
Correct Answer: Meiosis with recombination
Q28. Which phylum includes organisms with jointed appendages and segmented bodies relevant to natural product screening?
- Mollusca
- Arthropoda
- Chordata
- Annelida
Correct Answer: Arthropoda
Q29. In microbial ecology, culture-independent techniques are preferred because:
- All microbes can be cultured easily
- Culturing selects for a small fraction of community diversity
- They are cheaper than culturing
- They always provide full genome sequences
Correct Answer: Culturing selects for a small fraction of community diversity
Q30. Which is an example of a homologous structure indicating common ancestry?
- Wing of bat and wing of insect
- Flipper of whale and forelimb of human
- Eye of octopus and eye of human
- Cactus spines and pine needles
Correct Answer: Flipper of whale and forelimb of human
Q31. Which type of speciation occurs when populations are geographically isolated?
- Sympatric speciation
- Peripatric speciation only in plants
- Allopatric speciation
- Instantaneous speciation
Correct Answer: Allopatric speciation
Q32. Which cellular component is targeted by β-lactam antibiotics, making bacterial classification by cell wall important?
- DNA gyrase
- Peptidoglycan synthesis (cell wall)
- Ribosomal 30S subunit
- Cell membrane sterols
Correct Answer: Peptidoglycan synthesis (cell wall)
Q33. Which taxonomic author is considered the father of modern taxonomy and binomial nomenclature?
- Charles Darwin
- Gregor Mendel
- Carolus Linnaeus (Linnaeus)
- Ernst Haeckel
Correct Answer: Carolus Linnaeus (Linnaeus)
Q34. Which of the following is true about protists?
- All protists are multicellular photosynthetic organisms
- Protists include diverse unicellular eukaryotes like algae and protozoa
- Protists lack a nucleus
- Protists are classified within Kingdom Plantae
Correct Answer: Protists include diverse unicellular eukaryotes like algae and protozoa
Q35. Which term refers to genetic variation within a single species important for breeding medicinal plants?
- Ecosystem diversity
- Species richness
- Genetic diversity
- Clade diversity
Correct Answer: Genetic diversity
Q36. Which technique directly sequences environmental DNA without prior culture?
- Traditional plating
- Metagenomic sequencing
- Gram staining
- Biochemical tests
Correct Answer: Metagenomic sequencing
Q37. Which feature distinguishes fungi from plants?
- Presence of chlorophyll
- Cell wall composed of chitin in fungi vs cellulose in plants
- Multicellularity only in plants
- Fungi perform photosynthesis
Correct Answer: Cell wall composed of chitin in fungi vs cellulose in plants
Q38. Which level of biodiversity includes variation of habitats, ecosystems and ecological processes?
- Genetic diversity
- Species diversity
- Ecosystem diversity
- Population diversity
Correct Answer: Ecosystem diversity
Q39. Which phenomenon can lead to the emergence of new drug-resistant bacterial strains during treatment?
- Stabilizing selection
- Antibiotic selection pressure favoring resistant mutants
- Decreased mutation rates
- Loss of plasmids carrying resistance genes
Correct Answer: Antibiotic selection pressure favoring resistant mutants
Q40. Which of the following best explains polyphyletic groups?
- Group includes all descendants of a common ancestor
- Group lacks the most recent common ancestor and includes unrelated lineages
- Group includes ancestor and some descendants
- Group based solely on molecular data
Correct Answer: Group lacks the most recent common ancestor and includes unrelated lineages
Q41. Endophytes are microorganisms that live inside plants; why are they significant for B. Pharm students?
- They always cause plant disease
- They can produce novel bioactive compounds useful in drug discovery
- They decrease plant secondary metabolite production
- They are easily cultured and irrelevant to pharmacology
Correct Answer: They can produce novel bioactive compounds useful in drug discovery
Q42. Which method is most appropriate to determine evolutionary relationships using whole-genome comparisons?
- Morphological keying
- Molecular phylogenomics
- Gram staining
- Biochemical fermentation tests
Correct Answer: Molecular phylogenomics
Q43. Which of the following organisms lacks a true nucleus and membrane-bound organelles?
- Fungi
- Protozoa
- Archaea
- Plants
Correct Answer: Archaea
Q44. Which classification change is most likely when molecular data conflict with morphological classification?
- Molecular data is ignored in all cases
- Taxonomy may be revised to reflect phylogeny based on molecular evidence
- Organisms are split arbitrarily
- Morphological traits are considered more objective
Correct Answer: Taxonomy may be revised to reflect phylogeny based on molecular evidence
Q45. What role do keystone species play in ecosystem diversity relevant to medicinal resource stability?
- They have no significant ecological impact
- They disproportionately influence ecosystem structure and biodiversity
- They always cause decline of medicinal plants
- They increase only genetic diversity without affecting others
Correct Answer: They disproportionately influence ecosystem structure and biodiversity
Q46. Which characteristic is typical of cyanobacteria and critical for ecological primary production?
- Chemolithotrophy only
- Oxygenic photosynthesis using chlorophyll a
- Absence of photosynthetic pigments
- Strict heterotrophy
Correct Answer: Oxygenic photosynthesis using chlorophyll a
Q47. Which approach helps prevent misidentification and adulteration of medicinal plants?
- Relying solely on vernacular names
- Integrating morphological identification with DNA barcoding
- Using only organoleptic tests
- Assuming closely related species are identical in chemistry
Correct Answer: Integrating morphological identification with DNA barcoding
Q48. Which of the following best describes a paraphyletic group?
- Includes a common ancestor and all its descendants
- Includes multiple unrelated ancestors
- Includes a common ancestor and some, but not all, descendants
- Always based on molecular data only
Correct Answer: Includes a common ancestor and some, but not all, descendants
Q49. Which process explains rapid emergence of diverse phenotypes in isolated island populations?
- Genetic drift and founder effects leading to divergence
- Immediate global gene flow
- Stabilizing selection maintaining ancestral traits
- Universal hybrid vigor
Correct Answer: Genetic drift and founder effects leading to divergence
Q50. Which practice is an example of ex situ conservation relevant to preserving medicinal plant diversity?
- Protecting species in their natural habitat with park management
- Establishing botanical gardens and seed banks
- Allowing uncontrolled harvesting
- Ignoring local community involvement
Correct Answer: Establishing botanical gardens and seed banks
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