Diversity in Living Organisms Class 9 Science Important Questions

Please refer to Diversity In Living Organisms Class 9 Science Important Questions with solutions provided below. These questions and answers have been provided for Class 9 Science based on the latest syllabus and examination guidelines issued by CBSE, NCERT, and KVS. Students should learn these problem solutions as it will help them to gain more marks in examinations. We have provided Important Questions for Class 9 Science for all chapters in your book. These Board exam questions have been designed by expert teachers of Standard 9.

Class 9 Science Important Questions Diversity In Living Organisms

1 Mark Questions

Question. What is evolution?
Answer. Evolution is the gradual unfolding of organisms from the pre-existing ones through changes since the beginning of life.

Question. What makes the basic distinction in the body design of organisms? 
Answer. The type of cells whether prokaryotic or eukaryotic is a characteristic that makes a basic distinction in the body design of organisms.

Question. Define species
Answer. All organism that are similar enough to breed and perpetuate is called species.

Question. Which are the beings that constitute the kingdom Monera?
Answer. The kingdom Monera is the kingdom of the prokaryotes, composed of bacteria and archaebacteria.

Question. Give one example of each Protesta having cilia and flagella.
Answer. Cilia – Paramecium.
Flagella – Euglena.

Question. What are saprophytes?
Answer. Saprophytes are organisms which use decaying organic material as food. Eg., Rhizopus, yeast.

Question. What is a thallus?
Answer. Thallophyte has a simple plant body. The plant body is not differentiated into root, stem and leaves and is called thallus.

Question. Ingestion of solid food occurs in which type of nutrition?
Answer. Ingestion of solid food occurs in holozoic type of nutrition.

Question. What is chemical characteristics of fungal cell wall?
Answer. In fungi, the cell wall is made of chitin.

Question. What is pseudocoelom?
Answer. The space between alimentary canal and body wall that lacks lining of mesodermal epithelium is known as pseudocoelom.

Question. What is the morphological feature of molluscs after which the phylum is named?
Answer. The word “mollusc” means “soft thing”. Molluscs have soft bodies and this feature explains the name of the phylum.

Question. What is osculum?
Answer. The body of sponge is porous and the pores are called ostia. Single large opening or pore is called osculum.

Question. Name two phyla which have open circulation:
Answer. Anthropoda, Mollusca and Echinodermata

Question. What are the two mains divisions of the Phylum Chordate?
Answer. Chordates are divided into protochordates and vertebrates.

Question. Define radial symmetry?
Answer. Radial symmetry means that the left and the right halves of the body have the same design.

2 Mark Questions

Question. Give one word for the following:
i. The smallest unit of classification
ii. The largest unit of classification
iii. A collection of related species
iv. A group of related families
Answer. i. Species
ii. Kingdom
iii. Genus
iv. Order

Question. Animals that belong to the phylum Coelenterata are diploblastic. What do we mean by diploblastic animals?
Answer. Diploblastic animal means animals having body made of two embryonic or germ layersof cells. Body walls of animals belonging to phylum coelenterata are made up of two germ layers, of which the outer layer is called ectoderm and inner is endoderm.

Question. Which type of symmetry is present ina)
a) Starfish
b) Earthworm
Answer. a) Starfish- Radial symmetry
b) Earthworm- bilateral symmetry

Question. Why blue green algae are included under Monera and not under Plantae?
Answer. (i) Nuclear material is not enclosed with nuclear membrane and cell organelles are also not enclosed with membrane.
(ii) Do not show multicellular body design.

Question. Name the two subkingdoms of plant kingdom.
Answer. Eichler in 1883 suggested a system to classify the plant kingdom which is well accepted. He said that the plant kingdom is subdivided into two
subkingdoms: Cryptogamae and Phanerogamae.

Question. Define moss.
Answer. Mosses are non-vascular plants in the land plant division Bryophyta.
Mosses reproduce using spores, not seeds and have no flowers. e.g., Funaria, Bryum, Sphagnum

Question. Why are bryophytes called amphibians of the plant kingdom?
Answer. Bryophytes are also called amphibians of the plant kingdom because they can live on soilbut need water for sexual reproduction. They are usually found in damp, humid and shaded localities.

Question. Name the scientists who gave 2-kingdom and 5-kingdom classification respectively.
Answer. Two kingdom classification was given by Carolus Linnaeus
Five kingdom classifications were given by Robert H. Whittaker.

Question. Why do we classify organisms?
Answer. Classification makes the study of organisms much easier as there are millions of life forms and we cannot study them one by one. We can study the different classes or groups much easily after classifying them.

Question. Name the locomotory organs in insects.
Answer. Many adult insects use six legs for walking. ie. They have three pairs of jointed legs that allows for rapid walking while always having a stable stance (posture). They also have two pairs of wings that are mostly used for flying.

Question. Give one use of lichen.
Answer. Lichens are great indicators in telling us how polluted the air is, because lichens aresensitive to polluted air and are the first to disappear in that case.

Question. Classify the following seeds into dicot and monocot : Wheat, Maize, Bean, Gram.
Answer. Dicot seeds – Bean, Gram.
Monocot seeds – Wheat, Maize

Question. Why are thallophytes called non-embryonic plants?
Answer. Thyllophytes have simple body (thallus) and their gametes are unicellular. After fertilisation, the zygote does not form an embryo. Therefore, these plants are called non-embryonic plants.

Question. Define triploblastic animals?
Answer. Animals having a body made of three germ layers namely, ectoderm, mesoderm and endoderm. Platyhelminthes are the first triploblastic animals.

Question. Define Aschelminthes:
Answer. Aschelminthes is a phylum of unsegmented, triploblastic, pseudocoelomate, cylindricalor thread-like worms having bilateral symmetry and body wall covered with cuticle and epidermis.

Question. Which are the morphological features that differentiate the beings of the phylum Annelida from nematodes and platyhelminthes?
Answer. Platyhelminthes are worms with flat bodies (flatworms), nematodes are worms with cylindrical but not segmented bodies (roundworms). Annelids are cylindrical worms with segmented bodies.

Question. Based of which character the phylum Echinodermata has been named?
Answer. In Greek, echinos means hedgehog, and derma means skin. Thus, these are spiny skinnedorganisms. Thus, the phylum Echinodermata has been named based on the presence of spiny skin.

Question. In which habitats do molluscs live? Name some examples of the phylum Mollusca?
Answer. Molluscs can be found in the sea, freshwater and in terrestrial environments. Snails, octopuses, squids and oysters are examples of molluscs.

Question. Which type of circulatory system do molluscs have? How can it be compared to the circulatory system of annelids?
Answer. With the exception of few, most of the molluscs have an open circulatory system, i.e., the blood circulates within vessels, from the heart, but it also fills open cavities. In annelids, the circulatory system is closed, i.e., the blood circulates only inside blood vessels.

Question. How is the skin of amphibians moist?
Answer. The skin of amphibians is moist because they are covered in a mucous coating. Theysecrete mucus to help them keep their skin moist which aids in their ability to  breathe through their skin. The mucous often contains other chemicals, like antibacterial or anti fungal to help protect the amphibian.

Question. What is the destination of the notochord in vertebrates and in protochordates?
Answer. In vertebrates, the notochord disappears and gives birth to the spinal column (vertebral column). In protochordates, the notochord remains for the rest of the life.

Question. What are the differences between vertebrates and the other chordates?
Answer. Vertebrates are different because they have a spinal column (vertebral column). In these animals the notochord of the embryonic stage is substituted by the vertebral column in adults.

Question. How many carnivores belonging to cat family did you see in the zoo?
Answer. What is given to them to eat?
Three (Lion, Tiger, Leopard) – Flesh of animals is offered to them for eating.

Question. (a) Birds and mammals share one common feature. Give details.
(b) Name the phyla in which animals have soft-bodies covered with a hard shell.
Answer. (a) Both birds and mammals have a four-chambered heart.
(b) Phylum-Mollusca have animals that have soft bodies covered with a hard shell.

Question. Why are air bladders present in fishes?
Answer. The air bladders help a fish to adjust its buoyancy in water. In other words it helps a fish float or sink no matter the size. Air bladder is also known as the swim bladder. The swim bladder allows the fish to move up and down through the water or remain motionless in one place.

Question. How does amphibian overcome the unfavourable conditions?
Answer. Some amphibians become inactive when conditions are unfavourable for survival. This period of inactivity is called aestivation when it occurs during hot, dry weather and hibernation when it occurs in response to cold temperatures. Activity resumes when favourable conditions return.

Question. What is a cold- blooded animal?
Answer. An animal whose body temperature changes with the temperature of the environment is called cold- blooded animals. E.g., Frogs, snake, lizards etc.

Question. How is the skin of amphibians different from pisces and reptiles?
Answer. Skin is smooth without scales and has mucus glands in the skin to keep the skin moist. Scales cover the skin of fishes to protect against water whereas reptiles skin has horny scales to protect against dry conditions.

Question. What is the group of the phylum Chordata that first colonized the terrestrial environment? From which habitat did they come?
Answer. Amphibians, partially aquatic partially terrestrial animals, were the first chordates that colonized the dry land. They came from the aquatic habitat and were originated from fishes. (Nevertheless the first completely terrestrial chordates were the reptiles).

3 Mark Questions

Question. Which do you think is a more basic characteristic for classifying organisms?
(i) The place where they live.
(ii) The kind of cells they are made of why?
Answer. Option (11).The kind of cells they are made up of is the more basic characteristic for classifying organisms. It is for the following reasons:
(i) Classifying organisms based on habitat can be misleading. In every place, different types of organisms may live. They may not have similarities except for the common habitat. For example- An elephant and rabbit both live on land but they differ from each other in a number of ways. Moreover, further sub-classification is also not possible.
(ii) Cells are the functional and structural unit of life. Primarily, we can differentiate an organism as unicellular or multicellular. Further sub-classification is also possible based on cell types, its complexity etc.

Question. Give three examples of characteristics used for hierarchical classification.
Answer. The three examples of characteristics used for hierarchical classification are
(1) Prokaryotic or eukaryotic
(2) unicellular or multicellular
(3) mode of nutrition autotrophic or heterotrophic.

Question. On what basis are plants and animals put into different categories?
Answer. The basic design in plants and animals is different based on the need to make their own food (in plants) or acquire it (in animals).
• Plants are autotrophic means they can make their own food, whereas animals cannot.
• Locomotion is another characteristic which separates animal and plants in the classification.
• Their body designs are also different based on this characteristic.
So, they are put into different categories.

Question. Which organisms are called primitive and how are they different from the so-called advanced organisms?
Answer. Groups of organisms which have ancient body designs that have not changed very much is called primitive or lower organisms. On the other hand, an organism acquired their particular body designs recently is called advanced or higher organisms. Primitive or lower organisms have simpler body design whereas advanced or higher organisms have comparatively more complex body design. Primitive organisms are considered at the first ladder on the evolutionary scale while the advanced organisms are considered at successive ladders on the evolutionary scale.

Question. Will advanced organisms be the same as complex organisms?
Why? How can we say that the classification of life forms will be closely related to their evolution?
Answer. (a) It is not always true that advanced organisms will have a complex body structure. But, there is a possibility that over the evolutionary time, the complexity in body design will increase. Therefore, at times, advanced organisms can be the same as complex organisms.
(b) As the characteristics that have come into existence earlier are likely to be more basic than characteristics that have come into existent later.

Question. What are the five kingdoms that R. Whittaker proposed? Also define the term ‘species’
Answer. R. Whittaker categorized organisms in the following five kingdoms:
Kingdom Monera, Kingdom Protista, Kingdom Fungi, Kingdom Plantae, kingdom Animalia.
Species is a basic category of taxonomic classification, ranking below a genus or subgenus and having related organisms capable of interbreeding.

Question. What is the criterion for classification of organisms as belonging to kingdom Monera or Protista?
Answer. Kingdom Monera
Organisms which are prokaryotes belong to the kingdom Monera. They are unicellularorganism which have no membrane bound nucleus and organelles.
Kingdom Protista
Organisms which are eukaryotes and unicellular belong to the kingdom Protista. They are organism with membrane bound definite nucleus and organelles.

Question. Name the levels of classification proposed by Linnaeus. What happens to the similarities among organisms as we go from top to bottom level?
Answer. Classification systems as proposed by Linnaeus use a hierarchical system in which organisms are placed into groups, at different levels, according to the features they share. These groups or levels are (from top to bottom)
1. Kingdom
2. Phylum
3. Class
4. Order
5. Family
6. Genus
7. Species

Question. Explain the basis for grouping of organisms into five kingdoms:
Answer. The basis for grouping of organisms into five kingdoms is-
(i) Nature of cells- either prokaryotic or Eukaryotic
(ii) Number of cells- Unicellular and multicellular
(iii) Presence or absence of cell wall
(iv) Mode of nutrition

Question. What are the important features of Kingdom Monera?
Answer. Kingdom Monera: It includes mainly bacteria, blue-green algae, or cyanobacteria
Important features of Monera:
– Absence of well-defined nuclear or membrane-bound organellesprokaryotic organisms.
– All of them are unicellular
– Can be autotrophic (like Cyanobacteria)or heterotrophic(mostly parasitic or saprophytic)
– Bacteria, blue-green algae and mycoplasma are the example organism belonging to the Monera kingdom.

Question. What is symbiotic? Give examples.
Answer. Symbiosis is a mode of heterotrophic nutrition. It is an interaction or interrelationship between two organisms for a mutual benefit or dependence. Lichen is an example for symbiotic nutrition. It is an association between algae and fungi. Algae are autotrophic and can manufacture food for fungi while fungi provide shelter, water and minerals to algae.

Question. While walking along roadside, Sunil asked his father, a biology teacher, whether some small, green, non-flowering, leafy and thalloid plants, having little differentiation of body and growing along pavement are of any use to us. Father answered that these plants are small but they play very important role in maintaining green cover on the land.
(i) To which group these small thalloid, green, non-flowering plants belong?
(ii) In what way bryophytes are useful to us?
(iii)Which other groups of plants act as colonizers of barren rocks and make land suitable for growth of higher plants? Do these plants play some role in pollution monitoring?
Answer. (i) These small thalloid, green, non-flowering plants belong to the group calledbryophytes.
(ii) Bryophytes are also used in horticulture as soil additives, ornamental material for cultivation, and for beautification of gardens.
(iii) Mosses and Lichens act as colonizers of barren rocks and make land suitable for growth of higher plants. They are also good indicators of atmospheric quality.

Question. Why are cotyledons called seed leaves?
Answer. Cotyledons are actually part of the seed. They are the first part of the plant to emerge and they look like little green leaves (hence seed leaves). The cotyledons store food reserves for the growing seedlings. The plant relies on this stored food for early growth. The cotyledons can photosynthesise which supplies extra energy until the first true leaves emerge.

Question. What are the general characteristics found in all animals?
Answer. General characteristics found in all animals are-
• All animals are multicellular, eukaryotic and heterotrophic
• All exhibit locomotion
• Most of the animals have sense organs and nervous system
• Nutrition is generally ingestive
• Reproduction is generally sexual.

Question. State the major divisions in the Plantae:
Answer. Major division in Plantae are:-
(i) Thalophyta.
(ii) Bryophyte.
(iii) Pteridophyta.
(iv) Gymnosperms.
(v) Angiosperms.

Question. State the criteria for deciding divisions in plants?
Answer. The criteria depends upon:-
(i) Differentiation of plant body components.(ii) Presence of transport tissues (vascular tissues)
(iii) Ability to produce seeds.
(iv) Seeds are enclosed in fruits or naked.

Question. Describe the characteristic feature of Thyllophyta with examples:
Answer. Thyllophyta includes mainly algae and these plants are predominantly aquatic. It includes Spirogyra, Ulothrix, Cladophora and Chara
• Plant body is thallus- not differentiated into true root, stem and leaves.
• May be unicellular or multicellular
• Cell wall is made of cellulose and reserve food material is starch.
• They have naked embryos called spores.

Question. Describe the characteristics feature of Bryophyta with examples:
Answer. Division Bryophyta are also called amphibians of plant kingdom:
It includes mosses, Riccia, Marchantia
Characteristic feature of Bryophyta:
• Vascular tissues namely xylem and phloem, or the conduction of water and other substances from one part of the plant body to another are absent.
• Body is differentiated into stem and leaf-like structures.
• Naked embryo called spores is present.

Question. Describe the characteristics feature of Pteridophyta with examples:
Answer. Division Pteridophyta: Includes ferns, Marsilea, Equisetum
Characteristic feature of Pteridophyta
• Specialised vascular tissues for the conduction of water are present.
• Plant body is differentiated into true root, stem and leaves.
• Naked embryo called spores are present but seed formation is lacking

Question. How angiosperms are divided further?
Answer. Angiosperms are divided into 2 groups on the basis of the number of cotyledons present in the seed.
Monocotyledonous or monocots: These are the plants with seeds having a single cotyledon.E.g., maize, wheat, rice etc
Dicotyledonous or dicots: These are plants with seeds having two cotyledons. E.g., Pea, gram, bean etc

Question. Give any 5 difference between monocot and dicot plants
Answer.

Question. Give uses of lichens.
Answer. i) One of the most important uses of lichens is their sensitivity to pollution.
ii) Lichens have been used for centuries to create natural dyes for fabrics.
iii) Many lichens contain acids and other essential oils that are useful in making perfumes and scents.
iv) Some lichens are used in medicines

Question. Name some edible fungi and their uses.
Answer. Edible fungi and their uses are as follows
(i) Yeast has been used as leavening agent for the production of bread
(ii) The first antibioticused in modern medicine, penicillin, was isolated form Penicillium
(iii) Mushrooms have fleshy fruit body with certain aroma and flavors as well as good nutritional properties and are used mostly as food.
(iv) Fungi such as the Chinese caterpillar fungus, which parasitize insects, can be extremely useful for controlling insect pests of crops

Question. Bacteria, fungi and plants all have the cell wall, but they are placed in the different groups or division. Why?
Answer. Bacteria, fungi and plants showed a characteristic difference in their walls composition – In bacteria, the cell wall is made of peptidoglycans; In fungi, the cell wall is made of chitin (the same substance that makes the exoskeleton of arthropods) In plants, the cell wall is made of cellulose too. Therefore, bacteria, fungi and plants are placed in the different groups or division.