Systematics
Short Questions and Answers
One Mark Questions with Answers
1. Systema Naturae is a book written by
(a) Bentham and Hooker
(b) John Ray
(c) Lamarck
(d) Linnaeus
Answer: (d) Linnaeus
2. Basic unit of classification is
(a) genus
(b) species
(c) order
(d) class
Answer: (b) species
3. Branch of biology dealing with classification is
(a) ecology
(b) biography
(c) taxonomy
(d) eugenics
Answer: (c) taxonomy
4. Taxon is
(a) any type of taxonomy grouping like species, family or phylum based on similarity of traits
(b) a rank in hierarchial classification
(c) a group of closely related families
(d) a group of closely related organisms
Answer: (a) any type of taxonomy grouping like species, family or phylum based on similarity of traits
5. In binomial nomenclature, every organism has
(a) two names, one Latin other common
(b) two names, one scientific other common
(c) two names by two scientists
(d) one scientific name with two words, a generic and specific
Answer: (d) one scientific name with two words, a generic and specific
6. System of classification proposed by Linnaeus is
(a) sexual system of classification
(b) natural system of classification
(c) traditional system of classification
(d) artificial system of classification
Answer: (d) artificial system of classification
7. Which of the following is species?
(a) chordate
(b) mammalia
(c) carnivore
(d) Canis familaris
Answer: (d) Canis familaris
8. In biological terminology, a group of similar organisms which are capable of interbreeding, forming fertile offspring is
(a) species
(b) genus
(c) tribe
(d) family
Answer: (a) species
9. First step in taxonomy is
(a) naming
(b) identification
(c) description
(d) classification
Answer: (b) identification
10. The term ‘New Systematics’ was introduced by
(a) Linnaeus
(b) A. P. Candolle
(c) Julian Huxley
(d) Bentham and Hooker
Answer: (c) Julian Huxley
11. Taxonomy that takes into consideration evolutionary units within a species by knowing their genetic interrelationships, is known as
(a) biochemical taxonomy
(b) numerical taxonomy
(c) cytotaxonomy
(d) experimental taxonomy
Answer: (d) experimental taxonomy
12. Criteria employed for present day classification of organisms are based on
(a) resemblance in external features
(b) Anatomical and physiological traits
(c) ecological adaptation
(d) breeding habits
Answer:(b) Anatomical and physiological traits
13. Who made significant contribution in the field of classification?
(a) Pasteur
(b) Darwin
(c) Linnaeus
(d) Stanley Miller
Answer: (c) Linnaeus
14. Founder of binomial nomenclature was
(a) Linnaeus
(b) Mendel
(c) Darwin
(d) Lamarck
Answer: (a) Linnaeus
Two Marks Questions with Answers
1. Define numerical taxonomy.
Answer: It is type of taxonomy which evaluates resemblances and differences or primitiveness and advancement through statistical methods based on large number of characters obtained from all disciplines of biology followed by computer analysis. It establishes the numerical degree of relationship among individuals.
2. Why cannot the vernacular names be used by biologist? Give any two reasons.
Answer: The vernacular names cannot be used by biologist due to the following:
(a) all organisms do not occur in an area.
(b) all organisms occurring in a particular area cannot be given common names because some of them are microscopic or are unimportant to human affairs.
(c) some common names have incorrect meaning, example, silverfish, jellyfish, cuttlefish, starfish. They belong to different phyla and have no relationship with true fishes.
3. Write a brief note on taxon.
Answer: It is a unit in classification which may represent any level of grouping of organisms based on certain common characteristics like maize (species), roses (genus), grasses (family) conifers (order), dicots (class), seed plants (division). The term was introduced for the first time by ICBN during 1956. Mayr (1964) has defined taxon to be a taxonomic group of any rank that is sufficiently distinct to be worthy of being assigned to a define category. Simpson (1961) recognizes taxon to be a group of real organisms recognised as a formal unit at any level of hierarchical classification.
4. Why have unicellular algae been not kept in kingdom Protista by Whittaker?
Answer: A distinction between unicellular and multicellular organisms is not possible in case of algae. It is because of this that unicellular green algae have not been included in kingdom protista by Whittaker.
5. Name two feature of prokaryotes, one of which should be about genetic material.
Answer: Prokaryotes have a naked genetic material without being organised into a nucleus, a single envelope organisation, absence of spindle apparatus, meiosis and sexual reproduction.
Three Marks Questions with Answers
1. Differentiate between the artificial and natural system of classification.
Answer: Artificial system is highly useful in the field for quick identification of organisms while natural system often employes artificial keys for quicker identification in the field because the system as such is difficult to operate in the field.
Artificial system often utilizes one or two morphological traits while natural system employs several morphological characters for grouping of organisms. Artificial system may use habit and habitat as a criterion for grouping while a natural system never uses habit and habitat as criteria for classification. Artificial system does not employ characters from anatomy, cytology, cytochemistry, biochemistry, genetics, ontogeny for grouping of organism while natural system employs all these informations. Artificial system gives no information about natural relationships of phylogeny while natural system gives information about both natural relationships and phylogeny. Artificial system often results in placing of unrelated organisms in a group while while in natural system there is little chance of placing of unrelated organisms in a group.
2. What is artificial system of classification?
Answer: It is a system of classification which uses one or two morphological characters for grouping of organisms. Some artificial systems have used habit and habitat for this purpose Pliny applied artificial system of classification to both plants and animals. This classification divides plants and animals into land, air and water. Pliny distinguished animals into flight and non flight ones. Flight animals included bats, birds and insects. Linnaeus also put forward and artificial system of plant classification on the basis of numerical strength of sex organs like monandria, diandria, polyandria etc.
3. What are the drawbacks of artificial system of classification.
Answer: (a) The characters picked up for artificial system of classification show progressive, retrogressive or parallel evolution. Therefore they do not reflect any natural relationship.
(b) Organisms do not show clear-cut evolutionary line. In some characters they may be more advanced than their relative while in others they may be primitive.
(c) Organisms of different affinities get arranged in the same group like birds, bats and insects in flight animals or cacti, euphorbias and halophytes among succulent plants.
(d) Organisms of close affinities get separated into different groups example bat, whale and rat etc.
(e) Some characters used in artificial system of classification get changed with change in environment like biennial and annual habitat of radish, large and small leaves.
(f) The system does not give any idea about natural relationships among different taxa
4. What is natural system of classification?
Answer: It is a system of classification which takes into consideration comparable study of a new number of characters so as to bring about natural similarities and dissimilarities and hence natural relationships among the organisms. The system employs those characters which are relatively constant. They include morphological characters, anatomical characters, cytological characters, physiology, ontogeny or development, reproduction cytochemistry and biochemistry, experimental taxonomy, etc. The characteristics are helpful in bringing out maximum number of similarities in a group and comparable differences with other groups of organisms. For example, mammals are characterized by the presence of mammae, hair, vivipary, four chambered heart etc. Birds possess wings, feathers, four chambered heart etc. Similarly fishes do not possess limbs but fins. Natural system of classification not only brings out natural relationship but also studies the evolutionary tendencies and phylogeny with the help of all available data including fossils.