Diversity in Living Organisms For Class 9 Important Questions
Q 1 – Which organisms are called primitive?
Primitive organisms are those which have ancient body design and have not changed very much with the passage of time.
Q 2 – What is evolution?
The life forms that exist today have risen because of changes in their body design over a course of time to adapt themselves in the changing conditions. This is called evolution.
Q 3 – Why was the method of classification of animals proposed by Aristotle not accepted?
Aristotle classified animals on the basis of their habitat, i.e., whether they live on land or in water. But these animals, otherwise are very different from each other in many respects and such a classification does not prove much helpful. So, the method of classification by Aristotle was not accepted.
Q 4 – What are mycoplasma?
Mycoplasmas are the smallest and the simplest organisms. They are prokaryotes having nucleoid. They have heterotrophic mode of nutrition and their body can change forms easily. They are also called as MLO, i.e., Mycoplasma Like Organisms.
Q 5 – What is notochord? What is its function?
Notochord is a long rod-like support structure that runs along the back of the animals, separating the nervous tissue from the gut. It acts as a supporting structure by providing a place for muscles to attach for the ease of movement.
Q 6 – Give reasons why mosses are found in humid and moist areas.
Ans. The entire body of moss in damp humid places can absorb water. Moreover, sperms in mosses are flagellated and so they can reach the archegonia only in presence of water. Thus, water is indispensable in the life cycle of mosses for reproduction as well as for performing other physiological functions.
Q 7 – What is binomial nomenclature?
Ans. In binomial nomenclature, name of every organism is composed of two components—the first one is generic (genus) and the second one is specific (species). Also, the generic name starts with a capital letter whereas the specific name starts with small letter. For example, the scientific name of man is “Homo sapiens”. Here “Homo” is the generic and “sapiens” is the specific name.
Q 8 – Endoskeleton of fishes are made up of cartilage and bone. Classify the following fishes as cartilagenous or bony:
Torpedo, Sting ray, Dog fish, Rohu, Angler fish, Exocoetus
Torpedo — Cartilagenous,
Dog fish — Cartilagenous
Angler fish — Cartilagenous
Sting ray — Cartilagenous
Rohu — Bony
Exocoetus — Bony
Q 9 – How is notochord different from nerve cord?
Notochord is the skeletal rod which lies lengthwise between the central nervous system and the alimentary canal or the gut and the chordates possess it at young stage of development. In adult vertebrates, it is replaced by vertebral column. On the other hand, a nerve cord is a solid strand of nervous tissue, forming part of central nervous system, especially of invertebrates. The main difference between the two is that notochord is a part of skeleton system whereas nerve cord is a part of nervous system.
Q 10 – Write names of few thallophytes. Draw a labelled diagram of Spirogyra.
Ans. Ulothrix, Spirogyra, Cladophora, Ulva and Chara are few thallophytes.
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Q 11 – You are given leech, Nereis, Scolopendra, prawn and scorpion and all have segmented body organisations. Will you classify them in one group? If no, give the important characters based on which you will separate these organisms into different groups.
Ans. All organisms given in the question do not belong to same group. Leech and Nereis belong to phylum annelida because they have metamerically segmented body, i.e., body is divided into many segments internally by septa. Body segments are lined up one after the other from head to tail. But Scolopendra, prawn and scorpion belong to phylum arthropoda as these have jointed legs and open circulatory system.
Q 12 – Find out incorrect sentence:
(a) Protista includes unicellular eukaryotic organisms
(b) Whittaker considered cell structure, mode and source of nutrition classifying the organisms in five kingdoms
(c) Both Monera and Protista may be autotrophic and heterotrophic
(d) Monerans have well defined nucleus
(d) Monerans have well defined nucleus
Q 13 – Which among the following produce seeds?
(a) Thallophyta
(b) Bryophyta
(c) Pteridophyta
(d) Gymnosperms
(d) Gymnosperms
Q 14 – Which among the following have open circulatory system?
(i) Arthropoda
(ii) Mollusca
(iii) Annelida
(iv) Coelenterata
(a) (i) and (ii)
(b) (iii) and (iv)
(c) (i) and (iii)
(d) (ii) and (iv)
(a) (i) and (ii)
Q 15 – In which group of animals, coelom is filled with blood?
(a) Arthropoda
(b) Annelida
(c) Nematoda
(d) Echinodermata
(a) Arthropoda
Q 16 – Which one is the most striking or (common) character of the vertebrates?
(a) Presence of notochord
(b) Presence of triploblastic condition
(c) Presence of gill pouches
(d) Presence of coelom
(a) Presence of notochord
Q 17 – Who introduced the sytem of scientific nomenclature of organisms?
(a) Robert Whittaker
(b) Carolus Linnaeus
(c) Robert Hooke
(d) Ernst Haeckel
(b) Carolus Linnaeus
Q 18 – One of the following is not an Annelid?
(a) Nereis
(b) Earthworm
(c) Leech
(d) Urchins
(d) Urchins
Q 19 – Real organs are absent in
(a) Mollusca
(b) Coelenterata
(c) Arthropoda
(d) Echinodermata
(b) Coelenterata
Q 20 – Differentiation in segmental fashion occurs in
(a) Leech
(b) Starfish
(c) Snails
(d) Ascaris
(a) Leech