All Free Biology MCQs with Answers

2421. Biosystematics aims at:

• A. The classification of organisms based on broad morphological characters
• B. Delimiting various taxa of organisms and establishing their relationships
• C. The classification of organisms based on their evolutionary history and establishing their phylogeny on the totality of various parameters from all fields of studies
• D. Identification and arrangement of organisms on the basis of their cytological characteristics

Explanation: Biosystematics is the study of identification, nomenclature classification, and relationships among living beings. In other words, it is the study of the diversity of organisms, their comparative and evolutionary relationships based on comparative anatomy, ecology, physiology, biochemistry, and other fields. Biosystematics plays a crucial role in various scientific fields, including ecology, conservation biology, and evolutionary biology. It helps scientists understand the biodiversity of the planet, make informed conservation decisions, and contribute to our knowledge of the tree of life.

2422. Which of the following is less general in characters as compared to genus?

• A. Species
• B. Division
• C. Class
• D. Family

Explanation: A taxonomic hierarchy is the sequence of arrangement of taxonomic categories in descending order during the classification of an organism. There are seven obligate categories kingdom, division, class, order, family, genus, and species. Species is the lowest category while kingdom is the highest category. The number of common characters is maximum in the case of organisms placed in the lowest category. The number of common characters decreases with the rise in category. Species are the smallest group of individuals that can be recognized by ordinary methods as groups and which are consistently and persistently different from other groups because their characters are less general.

2423. 'Taxon' is the unit of a group of:

• A. Order
• B. Taxonomy
• C. Species
• D. Genus

Explanation: Taxon refers to all the categories in the taxonomic hierarchy. It may be a kingdom, class, order, family, genus, or species. It is any level of grouping of organisms. Each of these categories has been divided further into intermediate categories like subkingdom, subdivision, superclass, subgenus, subspecies, etc. This term was coined by ICBN in 1956.

2424. Linnaeus was credited with:

• A. Binomial nomenclature
• B. Theory of biogenesis
• C. Discovery of microscope
• D. Discovery of blood circulation

Explanation: Binomial nomenclature of scientific naming was first given by C. Linnaeus (1735) in his book Systema Naturae and later in "Species Plantarum" (1753). He used two Latin words for any organism, the first being a generic name and the second being a specific name. The generic name begins with a capital letter and the species name with a small letter. STB page # 83

2425. Sequence of taxonomic categories is:

• A. Class-phylum-tribe-order-family-genus- species
• B. Division-class-family-tribe-order-genus- species
• C. Division-class-order-family-tribe-genus- species
• D. Phylum-order-class-tribe-family-genus- species

Explanation: According to Biosystematics, To construct the hierarchy of classification, one or more species are grouped into a genus, one or more genera into a family, families are clubbed into order, orders into class, classes into phylum, and various phyla into kingdom.

2426. The term phylum was given by:

• A. Cuvier
• B. Haeckel
• C. Theophrastus
• D. Linnaeus

Explanation: The term phylum was coined in 1866 by Ernst Haeckel from the Greek phylon (φῦλον, "race, stock"), related to phyle (φυλή, "tribe, clan"). The concept of "phylum" was actually developed by the German biologist Ernst Haeckel (1834-1919) in the 19th century. Haeckel is credited with proposing the term "phylum" as a rank in the hierarchy of biological classification to group organisms with similar body plans and organizational features.

2427. A group of plants or animals with similar traits of any rank is:

• A. Species
• B. Genus
• C. Order
• D. Taxon

Explanation: A taxon (plural taxa) or taxonomic unit, is a name designating an organism or group of organisms. A taxon is assigned a rank and can be placed at a particular level in a systematic hierarchy reflecting evolutionary relationships.

2428. The basic unit or smallest taxon of taxonomy/classification is

• A. Species
• B. Kingdom
• C. Family
• D. Variety

Explanation: The basic unit or smallest taxon of taxonomy/classification is species. Species are a group of organisms that have numerous physical features in common and are capable of interbreeding and producing fertile offspring. Taxonomists use species as the starting point for organizing and categorizing living organisms into broader hierarchical groups. The hierarchy of biological classification, from most specific to most general.

2429. Linnaeus evolved a system of nomenclature called:

• A. Mononomial
• B. Vernacular
• C. Binomial
• D. Polynomial

Explanation: Binomial nomenclature of scientific naming was first given by C. Linnaeus (1735) in his book Systema Naturae and later in "Species Plantarum" (1753). He used two Latin words for any organism, the first being a generic name and the second being a specific name. The generic name begins with a capital letter and the species name with a small letter.

2430. Which of the following sets of diseases is caused by bacteria?

• A. Cholera and tetanus
• B. Typhoid and smallpox
• C. Tetanus and mumps
• D. Herpes and influenza

Explanation: Among all options, A is the correct one because both diseases are caused by bacteria. Cholera is caused by the bacterium Vibrio cholerae whereas tetanus is caused by the bacterium Clostridium tetani. All other options contain errors.