Detailed explanations in West Bengal Board Class 9 Life Science Book Solutions Chapter 1.3A Classification of Diversity of Life: Taxonomy offer valuable context and analysis.
WBBSE Class 9 Science Chapter 1.3A Question Answer – Classification of Diversity of Life: Taxonomy
Very Short Questions and Answers : (1 mark for each question)
Question 1.
Who introduced the concept of species?
Answer:
The concept of species was introduced by John Ray.
Question 2.
Name the scientist who gave the modern definition of species.
Answer:
Scientist Ernst Mayr (1966) gave the modern definition of species.
Question 3.
Name the systematic framework of classification with fixed number of rank.
Answer:
The systematic framework of classification with fixed number of ranks, is called hierarchy.
Question 4.
What is the scientific name of India’s national fruit?
Answer:
The scientific name of India’s national fruit (mango) is Mangifera indica.
Question 5.
What is the full form of ICZN?
Answer:
Full form of ICZN is International Code of Zoological Nomenclature.
Question 6.
Before which year, the published scientific names of animals were considered invalid?
Answer:
Before the year 1758 , the published scientific names of animals were considered invalid.
Question 7.
Name an aquatic animal having same common name and generic name.
Answer:
Octopus is an aquatic animal, having same common and generic name.
Question 8.
Give an example of a fish having same generic and specific name.
Answer:
Scientific name of catla fish (Catla catla) has same generic and specific name.
Question 9.
Name the branch of biology that deals with identification, classification and nomenclature of organisms.
Answer:
The branch of biology that deals with identification, classification and nomenclature of organisms, is known as taxonomy.
Question 10.
In which edition of ‘Systema Naturae’ was the binomial nomenclature of animals accepted by ICZN?
Answer:
In the 10th edition of ‘Systema Naturae’, the binomial nomenclature of animals was accepted by ICZN.
Question 11.
Which year’s edition of ‘Species Plantarum’ was accepted by ICBN for binomial nomenclature of plants?
Answer:
The edition of ‘Species Plantarum’ published in the year 1753, was accepted by ICBN for binomial nomenclature of plants.
Question 12.
Define characterisation.
Answer:
Characterisation is an important feature of taxonomy which involves the process of listing the identifying features of collected specimen.
Question 13.
Name a terrestrial animal, having same common and scientific name.
Answer:
Gorilla is a terrestrial animal, which has same common name and scientific name (Gorilla gorilla).
Question 14
Which type of organisms are mostly known by their scientific names?
Answer:
Most of the protozoa are known by their scientific names, such as Amoeba, Paramoecium etc.
Short Questions and Answers : (2 marks for each question)
Question 1.
How did the word ‘taxonomy’ originate?
Answer:
The word ‘taxonomy’ originated from two Greek words-‘taxis’ meaning ‘rank’ and ‘nomos’, meaning ‘law’ or ‘custom’. Therefore, the word ‘taxonomy’ literally means the ‘custom of ranking.’
Question 2.
What are the three basic features of Linnaean taxonomy?
Answer:
Three basic features of Linnaean taxonomy are-
- Characterisation of living organisms based on certain observable features
- Naming the organisms according to binomial nomenclature and
- Placing the individuals into seven major levels of hierarchical ranks.
Question 3.
Mention the elements of discussion under taxonomy.
Answer:
The main elements of discussion under taxonomy are-
- identification
- nomenclature
- classification and
- documentation.
Question 4.
What is meant by identification?
Answer:
Identification is a taxonomic process of separating out any organism from a cluster of other forms, on the basis of its distinctive features.
Question 5.
What does spot identification mean?
Answer:
Spot identification is the process of separating out any plant or animal instantly from a cluster of other forms, on the basis of some external features.
Question 6.
What is meant by categorisation or grouping?
Answer:
The taxonomic process by which any organism is placed under a taxon or rank, based on its similarities with the other members of that group, is called grouping or categorisation.
Question 7.
What is meant by nomenclature?
Answer:
Nomenclature is a taxonomic process of providing a scientific name to a properly identified plant or animal, according to the internationally accepted rules in order to distinguish it from others.
Question 8.
What is classification?
Answer:
Classification is a taxonomic process of placing or grouping organisms into proper taxonomic categories on the basis of similarities in characters.
Question 9.
What is meant by documentation?
Answer:
Documentation is the scientific method of preservation of the type specimens, their description and all relevant data in museum or in laboratories, after the completion of taxonomic processes like identification, nomenclature and classification of a specimen.
Question 10.
What are taxonomic categories?
Answer:
Taxonomic categories are the units in which plants or animals are grouped during classification. Species, genus, family, order, class, phylum etc. are the examples of different taxonomic categories.
Question 11.
What is taxon?
Answer:
Taxon is the basic unit of hierarchy, which is a rank, given to a group of organisms with similar features, during classification.
Question 12
What is systematics?
Answer:
According to Simpson (1961), systematics is the scientific study of the kinds and diversities of organisms and relationship among them. The terms, systematics and taxonomy, often complement each other.
Question 13.
Mention the main objective of systematics.
Answer:
The main objective of systematics is to assort different organisms on the basis of their similarities and dissimilarities, so as to determine the inter-relationship amongst them and to point out their origin and trend of evolution.
Question 14.
Mention two problems of using common name of organisms with example.
Answer:
Two problems of using common names are:
- Common names vary with regional languages, due to which an organism cannot be recognised universally. For example, crow is called ‘kak’ in bengali, ‘kawa’ in hindi, ‘corneille’ in french, ‘karasu’ in japanese etc.
- Common name may create identity crisis. For example, silver fish is an insect, but the name apparently indicates a fish.
Question 15.
What is Linnaean hierarchy?
Answer:
The five-category system of hierarchical classification system proposed by Linnaeus in the 10th edition of his famous book, ‘Systema Naturae,’ is known as Linnaean hierarchy. He classified the living organisms into five categories, which was later modified into seven categories.
Question 16.
What is binomial nomenclature?
Answer:
Binomial nomenclature is the method of providing a scientific name to an organism. The name should contain two distinct epithets, the first one being genus and the second one is species. For example, Panthera tigris is the binomial nomenclature of tiger.
Question 17.
What is trinomial nomenclature?
Answer:
Trinomial nomenclature is the method of providing a scientific name to an organism where the name should contain three distinct epithets, genus, species and sub-species. For example, Homo sapiens sapiens is the trinomial nomenclature of human.
Question 18.
Mention the seven categories of modified Linnaean hierarchy.
Answer:
Seven categories of modified Linnaean hierarchy, from highest to lowest rank are
Kingdom → Phylum → Class → Order → Family → Genus → Species.
Question 19.
What is meant by structure of hierarchy? Represent the structure of Linnaean hierarchy.
Answer:
- Structure of hierarchy: The arrangement of all categories of hierarchy from the base to the top collectively forms the structure of hierarchy.
- Structure of Linnaean hierarchy: The structure of Linnaean hierarchy can be respresented as follows-
Question 20.
Mention the importance of classification.
Answer:
The importance of classification are as follows-
- By means of classification, an organism can be sorted out easily and quickly from a cluster of organisms.
- Classification helps to determine the inter-relationship amongst different groups of organisms.
Long Questions and Answers : (5 marks for each question)
Question 1.
Write down the brief history of the development of taxonomy in the pre-Linnaean period.
Answer:
Pre-Linnaean development of taxonomic science
Taxonomy is one of the oldest branches of biology, which has developed gradually since ancient time. The developmental phases of taxonomy, according to the ages, have been discussed below.
(1) Ancient age: The concept of taxonomy has developed in India about 2500 years back. The glimpse of classification was noticed in Rig veda, Manusamhita and Agnipuran. Manu, an ancient sage, classified plants into oshadhi, banaspati, briksha, gulma, trina and balli. In ‘Briksha ayurveda’, Rishi Parashar (1500 BC) classified plants on the basis of morphological features.
Susruta, the famous ancient Indian medic, classified medicinal plants into 37 genera. Greek philosopher, Aristotle (384-322 BC) classified animal kingdom in two divisionsAnaima (having colourless blood) and Enaima (having red blood). Theophrastus (371-287 BC), the disciple of Aristotle, described 480 species of plants and classified those into trees, shrubs and herbs, in his famous book, ‘The Historia Plantarum’
(2) Roman age: Famous Roman naturalist Pliny the Elder (23-79 AD), classified plants in his book, ‘Naturalis Historia’ on the basis of their medicinal qualities. Roman physician Discordies, described about 600 medicinal plants in his famous book ‘The Materia Medica.’
(3) Middle age: Italian botanist Caesalpino (1583), in his famous book ‘The Plantis’, classified 1500 plants into trees, shrubs and herbs. In his classification, he put emphasis on the character of fruits and seeds. For this great work, Caesalpino is regarded as the pioneer of plant taxonomy.
Gaspard Bauhin (1596) classified 6000 species of plants in his famous book ‘Pinax’. He was the first person who tried to show the difference between genus and species. Famous scientist John Ray (1627-1705), classified plants based on the basis of the number of cotyledon of seeds in his book ‘Methodum Plantarum’.
Question 2.
Write down the brief history of the development of taxonomy in pre-Linnaean period.
Answer:
Unnaeus’s role in developing modern taxonomy:
Modern taxonomy was set into light after the work of great Swedish scientist Carolus Linnaeus. He was the pioneer of scientific classification of plants and animals. In 1751, he first suggested the concept of binomial nomenclature in his famous book Philosophia Botanica
He studied numerous plants and animals, which he described in the latest edition of his two famous books, ‘Species Plantarum’ (1753) and ‘Systema Naturae’ (1758), respectively.
Taxonomists of post-Linnaean period:
Augustin de Candolle (1799), George Bentham (1862-1883), Joseph Dalton Hooker (1855), Adolph Engler, Karl Prantl (1887-1915), John Hutchinson (1926), Ernst Mayr (1963) are some of t
he renowned scientists who have enriched the taxonomic science to a great extent in the post-Linnaean period.
In last twenty years, there was immense development noticed in the field of systematic classification of plant kingdom based on phylogenetic analysis. Takhtajan (1997), Cronquist (1981) etc. played promising role in this aspect.
Question 3
What is meant by taxonomic hierarchy? How did Linnaean hierarchy modify in course of time?
Answer:
Taxonomic heirarchy
Taxonomic hierarchy is the sequential arrangement of various categories or units of classification comprising of different taxa, from larger to smaller ranks. This includes seven categories.
Modification of Linnaean hierarchy
In course of time, newer variants of organisms have been discovered. Modern taxonomists faced problems in positioning those variants in the prevailing seven-step format. Consequently, Simpson (1961) suggested a
21-step hierarchy for animal classification.
In this format, a new step ‘tribe’ was being inserted in between genus and sub-family. Besides this, some intermediate steps were also inserted in between the main steps prefixed with ‘supra,’ ‘sub’ and ‘infra’. Later, ICBN proposed a 24-step hierarchy structure.
Here, few more new steps were introduced, namely ‘section’ and ‘series’ between genus and species and ‘variety, ‘form’ and ‘clone’ after species. However, the intermediate steps, prefixed with ‘supra’ and ‘infra’ are discarded. Thus, the old Linnaean hierarchy is modernised in course of time.
Question 4.
Describe every category of taxonomic hierarchy with example.
Answer:
Categories of taxonomic hierarchy
Taxonomic hierarchy includes seven categories or ranks, which are described below.
1. Kingdom: It is the topmost category of taxonomic hierarchy. All different phyla or divisions constitute a kingdom. American scientist, R H Whittaker (1969) classified the whole living world into five different kingdoms-Monera, Protista, Fungi, Plantae and Animalia. Example-Human belongs to kingdom ‘Animalia’ and mango tree belongs to kingdom ‘Plantae.’
2 Phylum/Division: Related classes of animals constitute a phylum. In case of plants, this category is known as division. Example-In case of human, phylum is ‘Chordata’ and for mango tree, division is ‘Angiospermae.’
3 Class: A class consists of several related orders.
Example-Human belongs to class ‘Mammalia’ and mango tree belongs to class ‘Dicotyledoneae.’
4. Order: Several related families add up to create an order. Example-Human belongs to the order ‘Primates’ and mango tree belongs to the order ‘Sapindales’.
5. Family: All related genus together comprise a family. Example-Family of human is ‘Hominidae’ and for mango tree, it is ‘Anacardiaceae’.
6 Genus: Several related species constitute a genus. Example-Genus of human and mango tree are Homo and Mangifera respectively.
7 Species: It is the lowest category of taxonomic hierarchy. The taxon under this category include the group of naturally interbreeding organisms, which remain reproductively isolated from other related groups.
Example-Species of human and mango tree are sapiens and indica respectively.
Question 5.
What are the advantages of hierarchical classification? Mention the systematic position of mango tree according to Linnaean hierarchy.
Answer:
Advantages of hierarchical classification
The advantages of hierarchical classification has been discussed below.
1. Inter-relation amongst groups: Hierarchical system of classification provides ready information necessary to determine inter-relationships amongst two groups of plants or two groups of animals.
2. Flawless grouping: Before this system of classification, characteristic features of the sample specimens were studied vividly. Emergence of this system of classification helps us to study the characteristics of the sample specimens more specifically. Therefore, the grouping becomes flawless.
3. Easy identification of taxon: From a hierarchical classification, any taxon can be easily identified.
4. Other advantages: In this system of classification, repetition of characteristic features does not occur amongst the taxa of higher and lower categories. Only additional similarities are added to the lower categories.
Systematic position of mango tree
The systematic position of mango tree has been represented below.
Question 6.
Mention the rules of binomial nomenclature.
Answer:
Rules of binomial nomendature
The basic principles of binomial nomenclature was initially proposed by Linnaeus. Later in the 19th and 20th century, several international bodies of taxonomy, namely ICBN, ICZN, ICBacN, ICVN and ICNCPP reviewed the prevailing rules and published the final edited version of the rules of binomial nomenclature. The most important rules are as follows—
1. Every organism must have a definite scientific name in Latin or Greek, comprising of two epithets – a generic name and a specific name.
2. Each of the epithets must not be composed of less than three or more than twelve roman alphabets. The generic name is a noun, which should be written first, starting with a capital letter.
3. A generic name cannot be repeated in any other organism of the same or different kingdom.
4. Specific name should be written after generic name. It should be written in small letters.
5. A specific name may be repeated under different genus.
6. The name of the discoverer may be mentioned in full or in abbreviation, after the specific name.
7. A scientific name should be printed in italics. If handwritten, each epithet should be separately underlined. For example, scientific name of mango tree should be written as Mangifera indica L. (Here L. stands for Linnaeus, the discoverer).
8. Any plant name, used before publication of ‘Species Plantarum’ (1753) and animal name, used before publication of 10th edition of ‘Systema Naturae’ (1758) must be discarded.
9. If a single organism is assigned two different names by two separate discoverers in different times, the former will be accepted and the latter will be discarded. This is known as Law of priority.
10. Detailed description with photograph of the sample used for nomenclature, must be published in any internationally accepted science journal. The type specimen, used for the nomenclature, must be preserved in any museum competent for such job.
Question 7.
Mention the systematic position of human according to taxonomic hierarchy and the important characteristic features of different taxa.
Answer:
Systematic position of human and characteristic features of different taxa
| MSBM | Taxon | Characteristic features |
| 1. Kingdom | Animalia | Multicellular, cells without plastids and cell wall, heterotrophic, capable of locomotion |
| 2. Phylum | Chordata | Notochord present at any stage of the life cycle, dorsal tubular nerve cord present, pharyngeal gill slits and post anal tail present |
| 3. Class | Mammalia | Body covered with hair, sweat glands and sebaceous glands present in skin, mammary glands and external pinna present |
| 4. Order | Primata or Primates | Palm and foot can grip any object, all digits have nails, vision is strong but sense of smell (olfactory sense) limited |
| 5. Family | Hominidae | Body erect, capable of bipedal movement, hands shorter than legs |
| 6. Genus | Homo | Brain is advanced and structurally complex, structure of palm is well developed (to use and prepare tools), capable of talking |
| 7. Species | sapiens | High forehead, distinct lower jaw-line, culturally advanced |