Chapter 7 Diversity in Living Organisms

RBSE Solutions for Class 9 Science Chapter 7 Diversity in Living Organisms

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Rajasthan Board RBSE Class 9 Science Chapter 7 Bio-Diversity

Bio-Diversity Textbook Questions Solved

Objective Type Questions

Question 1.
The highly advanced division of plant is:
(A) Bryophyta
(B) Angiosperm
(C) Gymnosperm
(D) Thallophyta
Answer: B

Question 2.
In which plant seed, vivipary is found
(A) Hydrophytes
(B) Mesophytes
(C) Xerophytes
(D) Halophytes
Answer: D

Question 3.
Sunken stomata in the leaves is an adaptation of:
(A) Xerophytes
(B) Halophytes
(C) Hydrophytes
(D) Mesophytes
Answer: A

Question 4.
In which plant division, plants are known as vascular cryptogams:
(A) Pteridophyta
(B) Bryophyta
(C) Gymnosperm
(D) None of these
Answer: A

Question 5.
An animal which belongs to phylum Arthopoda is:
(A) Leech
(B) Tapeworm
(C) House-fly
(D) Starfish
Answer: C

Question 6.
Name the father of binomial nomenclature of classification?
Answer
Carolus Linnaeus.

Question 7.
Does frog belong to which class?
Answer
Frog belongs to class Amphibia.

Question 8.
What is Adaptation?
Answer
The special characteristics which help the plants and animals to live successfully in a particular environment are called adaptations.

Question 9.
Who proposed the five kingdom classification?
Answer
Robert H. Whittaker in 1969.

Question 10.
Cynobacteria belongs to which kingdom?
Answer
Cynobacteria belongs to kingdom monera.

Question 11.
What is Lichen?
Answer
Lichen is a symbiotic life form, that grows on the bark of trees as coloured patches. It is an association between algae and fungi.

Question 12.
Give two examples of Gymnosperms?
Answer
Pinus and Cycas.

Question 13.
Name the animal which respire through gills, lungs and skin?
Answer
Frog from class Amphibia respire through gills, lungs and skin.

Question 14.
Name two animals which lay eggs?
Answer
Platypus and Echidna.

Question 15.
In which habitat mangrove vegetation is found?
Answer
Mangrove vegetation is found in halophytic, saline and marshy habitat.

Rajasthan Board RBSE Class 9 Science Chapter 7 Bio-Diversity

Bio-Diversity Short Answer Type Questions

Question 16.
Write the general characters of Halophytes?
Answer
Halophytes: These are a special type of xerophytes, which grow in saline soil with a high concentration of sodium chloride, magnesium sulphate and magnesium chloride and/or other salts. Halophytes are found near saline lakes (Sambhar lake) and on the coasts of oceans.

General characters of Halophytes:

• Halophytes of subtropical places are herbs, and those found in tropical zone are shrubs and trees.
• The roots do not penetrate much deeper.
• Adventitious roots that develop from the main stem of halophytic plants support these plants, after entering into the soil.
• A special type of roots is developed in halophytes, which are called pneumatophores. Each root is provided at the upper end, with numerous pores for the exchange of 02 and C02.
• Stems are fleshy and covered with hairs.
• The leaves of halophytes are less developed and fleshy.
• Most of the halophytes show vivipary. The seeds germinate inside the fruit, which is still attached to the parent tree. The germinated seeds fall on the soil and begin their development soon. Examples: Rhizophora and Sonnertia.

Question 17.
Write the adaptation found in aquatic animals?
Answer
Aquatic habitat is one of the most important habitats, where a large number of animals live. The aquatic, habitats include, both freshwater and marine water animals. Aquatic adaptations develop due to an aquatic mode of live animals, like those of fishes, mammals, like the seal, dolphin, whales, etc.
The structural and functional adaptations of aquatic animals are:

1. for movement.
2. for protection of the body.
3. for feeding.
4. for obtaining dissolved oxygen.
5. for remaining buoyant in water,
6. for balancing the fluctuations, in pressure.

The aquatic adaptations for aquatic animals to their aquatic life, are as follows:

1. The body of most of the aquatic animals is streamlined or spindle-shaped. Their body is laterally compressed and offers the least resistance to motion, as the fish swims.
2. The animals locomote in water by fins (in fishes), flippers (in whales) or, webbed feet (in frogs and ducks), for swimming in water.
3. The body is covered with waterproof, scales, cuticle, shell and a slippery substance for reducing the surface tension.
4. Aquatic animals possess the ability to feed in water.
5. Swimbladder and gills are the main respiratory organs in aquatic animals. Gills have a large surface area, to extract oxygen dissolved in water. In mammals, lungs are the respiratory organ.
6. Hair, skin glands and oil glands are absent, in aquatic animals.
7. Aquatic animals are generally larger in size.

Question 18.
Write the characteristics of Cryophytes?
Answer
Cryophytes: Cryophytes are the plants which grow in cold regions. Ex- Salmonella, moss, lichen etc. These plants grow when ice melts and complete their life cycle in a small period of time. They have short life-span e.g., plants like salmonella, a flowering plant, which grows when the ice melt with heat. Flower only grow outside the plant.

Question 19.
Write the characteristics of Class Mammalia.
Answer
Class-Mammalia: It includes big animals, like Kangaroo, bat, monkey, cow and man. Developed mammary glands are found in females, mothers feed milk to young ones secreted by mammary glands. Their body is divided into head, neck, thorax and tail. Hairs are present on the body. Ear pinnae (External ear) is present. They are warm-blooded. They respire through the lungs. The heart is four-chambered. The heart has 2 auricles and 2 ventricles. Most of the mammals are viviparous.
Examples are: Pteropus (bat), Homo (man), Herpestes (mongoose), Ratus (rat), Panthera (lion, tiger).

Question 20.
Write the characterises of Phylum Arthropoda?
Answer
Phylum Arthropoda means animals with jointed legs:

• The members of this phylum are multicellular, triploblastic, bilaterally symmetrical and have true coelom (body cavity)
• The exoskeleton of chitin is found on their body.
• Their body is divided into head, thorax and abdomen.
• Jointed appendages are found on each segment.
• Appendages are modified for different functions.

Examples are: Scorpion, Butterfly, Musca (house fly), Cancer (Crab).

Question 21.
In Gymnosperm plants, write the function of mycorrhiza and coralloid roots.
Answer
Gymnosperms are perennial plants. They are mostly trees or shrubs, e.g., Pinus. Pinus is evergreen plant and differentiated into root, stem and leaves. It has a taproot system. The main roots, however, is not very long and the lateral roots are extensively spread out. They show symbiotic association with soil fungus. This relationship is called mycorrhiza.

Coralloid root: In some plants, like cycas small adventitious branches arise from primary roots, in contact with cyanobacteria, which fixes the nitrogen from the atmosphere.

Question 22.
Explain Symbiosis in Lichens?
Answer
In lichens, the plant body has alga and fungus, living together and deriving benefit from one another. The fungus provides shelter to alga and also maintain the humidity inside the lichen body, necessary for the alga to undergo photosynthesis process properly. In return, the alga provides the food material, prepared during photosynthesis to the fungus. This association, in which the interacting plants.

Question 23.
Why the plants of Pteridophyta called Cryptogams?
Answer
The reproductive organs in pteridophytes are hidden and are very conspicuous. External flowers or seeds are absent and they have naked embryos called spores. The plants belonging to this group are, therefore, called ‘Cryptogams’.

Question 24.
Describe the adaptation found in Xerophytes plant?
Answer
Xerophytes occur in those habitats where scarcity of water is found.
They show the following characteristics:

• The root system is well developed, reaches quite deep in the soil to absorb water. Root hairs are abundant.
• Mechanical tissues in the stem are well developed. Stem possess dense hairs. It is spongy and stores water.
• Leaves are spiny or scaly, to reduce transpiration. Stomata are of a sunken type. The thick cuticle is present on the epidermis.
• Succulent xerophytes have fleshy leaves and stems which store water in their water storage tissues.

Question 25.
What are saprophytes?
Answer
Fungi are heterotrophic in nutrition and obtain food from decaying organic matter. So, they are called decomposers or saprophytes. They derive their nourishment from the dead remains of plants and animals. For example, Mucor, Rhizopus etc.

Question 26.
Define the two similarities between the Bryophyta and Pteridophyta group?
Answer
The reproductive organs in the bryophytes and the pteridophytes are hidden and are very conspicuous. External flowers or seeds are absent and they have naked embryos called spores. The plants in the three groups are, therefore, called Cryptogamae.

Question 27.
What are monocot and dicot plants?
Answer
Monocots: The seeds of these plants bear only one cotyledon. Their leaves have parallel venation. Roots are a fibrous and similar shape. Flowers bear three petals or multiple of three trimerous. Vascular bundles are closed and scattered, i.e., cambium is not found in closed bundles and hence, no secondary growth.
For example Maize, Rice, sugarcane, Wheat, Onion, Coconut, Grasses and banana. Dicots: The seeds of these plants bear two cotyledons. Venation in the leaves is reticulate. Root system includes tap root, primary and secondary roots, etc. Vascular bundles are arranged in a ring and open type, i.e., possess cambium, which is responsible for secondary growth. Flowers have five or multiple of five petals. For examples: Potato, pea, sunflower, rose, neem, apple, banyan etc.

Question 28.
Write the two differences between chordates and non-chordates?
Answer
Difference between Chordata and Non-Chordata

• Animals of sub-kingdom Chordata have a notochord, in some stage of their life. Non-chordate animals do not have a notochord, in any stage of their life.
• Chordates have nerve cord on the mid-dorsal surface. In non-chordates, nerve cord is absences, or if present then it is on the mid-ventral surface.
• Chordates have pharyngeal gill clefts in some stage of life. In non-chordates, the pharynx does not have any cleft at any stage of life.

Question 29.
What is the function of pneumatophores in Halophytes?
Answer
Halophytes are present in water-logged conditions and so, the roots in the soil do not get air for respiration. Thus, underground roots grow above the surface of the soil and are called aerial respiratory roots or pneumatophores. They are negatively geotropic. Aerial respiratory roots appear like conical spikes coming out of the water. They have numerous aerating pores, that help in respiration.

Question 30.
What is the function of assimilatory root in Trapa?
Answer
In Trapa, the assimilatory root becomes green for photosynthesis. These greenish roots remain hanging in the air. Their main function is photosynthesis. They manufacture food material for the plant.

Question 31.
Write the adaptation found in aerial animals?
Answer
The animals who live and flourish, mainly on land, but come to the trees or its branches for safety and shelter, are called arboreal animals. For example, monkey, flying lizard, flying squirrel, bats, birds, etc.
The bird and bats are adapted for the aerial mode of life. Main adaptation in aerial animals are as follows:

• The body of birds is streamlined i.e., spindle shaped, for the easy and swift passage through the air.
• Forelimbs are modified into wings, for flying in.
• The entire body of birds is covered by light, elastic and waterproof feathers. They also help in maintaining body temperature.
• Birds have hollow bones, strong flight muscles light body covering, sharp eyesight, modified beaks and tails. Birds do not have teeth and urinary bladder.
• Ovary and oviduct are single, lungs are provided with air sacs, which are air-filled and make the body light.
• The feet of birds are modified, for climbing and perching.

• 

  Rajasthan Board RBSE Class 9 Science Chapter 7 Bio-Diversity

  
  

Bio-Diversity RBSE Solutions Long Answer Type Questions

Question 32.
Classify plants, on the basis of habitat and describe all the adaptations found in Plants?
Answer
Adaptation: The special characteristics which help plants and animals to live successfully, in a particular environment are called adaptation.
Warming classified plants into the following categories, on the basis of available quantity of water in different environments:

1. Hydrophytes,
2. Xerophytes,
3. Halophytes,
4. Mesophytes.

1. Hydrophytes: The plants which grow in water or in very wet places are called hydrophytes. These plants are found in ponds, lakes or in rivers.

Adaptations in Hydrophytes are:

1. Roots are either absent or poorly developed. Root caps are absent.
2. Stems are long, slender, spongy and flexible. Mechanical tissue, sclerenchyma is absent or poorly
3. Leaves are thin, long and ribbon-shaped. Leaves floating on the surface of the water are generally long, cylindrical, smooth and dark coloured. On upper surface, a layer of wax-like substance is found.
4. All hydrophytes possess large air chambers and the tissue in which air chambers are present is called aerenchyma.

2. Xerophytes: These are the plants which grow in dry habitats, deserts.

Adaptations in Xerophytes are:

1. The roots of xerophytes are usually long, which go deep into the subsoil in search of water.
2. Leaves are small and modified into spines.
3. The thick cuticle is found on stems and leaves.

3. Halophytes: These are special types of xerophytes, which grow in saline soil, with high concentration of salts like sodium chloride, magnesium sulphate and magnesium chloride. Halophytes are found near saline lakes and on the coast of
oceans.
Adaptations in Halophytes are:

• A special type of roots grows underground in some plants, which rise vertically upwards, like many conical spikes. These roots are called pneumatophores. Each such root is provided at the upper end with numerous pores, for the exchange of vital gases i.e., oxygen and carbon dioxide.
• Most of the halophytes show vivipary. The seeds germinate inside the fruit, which is attached to the parent tree. When germinated, the seed falls on the soil and it begins to develop. Example Rhizophora.

4. Mesophytes: Plants that germinate under the average condition of temperature and moisture are called mesophytes.
Examples-Peepal, Neem. Maize, Wheat, Guava, etc.

Adaptations in Mesophytes are:

1. The root system is well developed and branched with root hairs.
2. The stem is solid, erect and branched.
3. The leaves are numerous, large, broad, thin or thick.

Question 33.
Write the conventions, while writing the scientific name followed by the Binomial method.
Answer
Nomenclature is a system of assigning scientific names to the organisms, listed in any classification. Scientific names consist of two words in which the first word represents the genus and the second word represents species. It is a unique name assigned to an organism and can be used to identify it, anywhere in the world. Certain conventions are followed while writing the scientific names:

• The name of the genus begins with a capital letter.
• When written by hand, the genus and the species names have to be underlined separately.
• When printed, the scientific name is given in italics.
• The name of the species begins with a small letter.

Question 34.
Describe the characteristics and examples of Aquatic and Desert animals?
Answer
Aquatic habitat is one of the most important habitats, where a large number of animals live. The aquatic habitat includes both fresh water and salt water habitats.
Adaptive features of aquatic animals are:

(1) Body shape: Body is streamlined and offers the least resistance to motion, like swimming.

(2) Swimming organs: The body is covered with waterproof scales and a slippery substance for reducing the surface tension. The flippers of whale, fins and tail of a fish help in increasing speed and changing direction.

(3) Air bladders: They are present in some fishes. It communicates with pharynx and filled with air.

(4) Respiratory organs are gills in fishes. Gills have the large surface area to extract oxygen dissolved in water.

In the amphibious adaptation, a frog is adapted for both aquatic and terrestrial life.

• limbs, through webbed feet, are adapted for swimming.
• Hind limbs are longer than forelimbs.
• Skin is always moist, which helps in breathing when the animal is on land.
• Fertilisation is external.

The animals living on land differ in their habits of living. The walkers and runners have cursorial adaptations, the borrowers have fossorial adaptations, climbers and fliers have arboreal adaptations. Animal living in deserts have desert adaptations.

Xeric adaptations of Desert animals:Animals such as camels, desert rats, rabbits, foxes, etc. have to adapt in order to overcome, xeric conditions.

Some xeric adaptations are as follows:

• Moloch absorbs water, like blotting paper. Its surface is covered by thorn like scales.
• Water cells are developed in the walls of a camel. It uses its entire foot while walking.
• The desert animals do not perspire and conserve water.
• The nostril of camel can be closed like eyelids. The eyelids are modified into the window like structure, which covers the eye.
• The ear opening is either small or protected by scales.
• The sense of light, hearing and smell are highly developed.

Question 35.
Describe the characteristics of Angiosperm and Gyw.nosperm Plants?
Answer
The characteristics of angiosperms are as follows:

• These are flowering plants. Their seeds develop inside an organ, which modifies to become a fruit.
  Plant embryos in seeds have structures, called cotyledons. Cotyledons are also called seed leaves because in many cases, they emerge and become green on seed germination. Endosperm has triploid cells.

The angiosperms are divided into two groups, on the basis of a number of cotyledons present in the seed.

• Dicotyledonous or Dicots plants.
• Monocotyledonous or Monocots Plants.

Gymnosperms:

• These plants are most primitive and bear seeds.
• The seeds produced are naked and are not enclosed within fruits.
• Plants are usually perennial, evergreen and woody. Sporophylls are aggregated to form cones, which are separated into male and female cones.
• Xylem lacks vessels and phloem lacks companion cells.
• They have haploid endosperm cells.

Question 36.
Write short notes on:(a) Mangrove vegetation.
(b) Amphibians of Plant kingdom.
(c) Mineral excretory glands.
(d) Lichen.
(e) Stilt roots.
Answer
(a) Mangrove vegetation: Halophytes are special types of xerophytes, which grow in saline soils. The soil has high concentrations of sodium chloride, magnesium sulphate and magnesium chloride. The plants that grow in saline and marshy soil are called halophytes.
General characters of Halophytes:

1. Halophytes of sub-tropical places are herbs, while those in tropical zone are shrubs and trees.
2. The roots do not penetrate much deeper into the soil.
3. Adventitious roots that develop from the main stems of halophytes, support these plants after entering into the soil.
4. A special type of roots develop from mangrove are called respiratory roots or pneumetophores. These are negatively geotropic roots. Each root is provided with numerous pores, towards the upper end for the exchange of O2 and CO2.
5.  The stem of some plants are fleshy and covered with hairs.
6. The leaves of halophytes are absent or little developed and fleshy.
7. The thick cuticle is found on the epidermis of stems and leaves.
8. The rate of evaporation is very less in these plants.
9. Carbonic acid is formed during respiration, due to special metabolic activities.
10. Mangrove plants show a special type of germination of their seeds known as
    vivipary. The seeds germinate inside the fruit, which is still attached to the parent tree. When germinated, seeds fall on the soil, it begins their development soon, e.g. Rhizophora and Sonneratia.

(b) Amphibians of Plant kingdom: Bryophytes are called the amphibians of the plant kingdom because they can live on land as well as in water.
In bryophytes, the true vascular system is absent, i.e., they do not have specialised tissues for the conduction of water and food materials, from one part of the body to another.
The body is commonly differentiated into stem and leaf-like structures. They lack real roots, stems, leaves, etc. and do not bear a flower.
Sex organs are multicellular and jacketed.
In these plants, an embryo is formed on fertilisation, e.g., Funaria, Riccia, Mosses, Marchantia (liverwort), Anthoceros and Antheridium (living fossils).

(c) Mineral excretory glands: These glands are found in the animals which are found in sea water. Saline water of oceans contains a large amount of various dissolved minerals. In order to excrete the minerals from the body, animals have mineral excretory glands.

(d) Lichens:

1. Lichens occur in all types of environment. They grow on rocks, leaves, the bark of trees and forest floor.
2. Lichen can be called a compound plant because an alga and a fungus live together in its thallus in mutual partnership and each gets to benefit from one another.
3. Fungus affords shelter to the alga and maintains humidity inside the thallus of lichen. Moisture is generally absorbed from the atmosphere. Algae manufacture the starch, which is used as food by the fungus.
4. Lichen thallus may be flat, leaf-like or branched and larger in size. For example:
   Crustose lichen, Foliose lichen and fruticose lichen.

(e) Vivipary: Vivipary means germination of the seed within the fruit, while it is still attached to the plant. Such plants are found in the saline soils of the coastal land and on the deltas and estuaries of the rivers of Bengal. This type of germination is essential in plants growing in saline, muddy soil. Due to greater concentration of salt in the water, the seeds are not able to germinate.

Besides coastal plants, vivipary is seen in other plants as well. In Sechium edule, papaya and coconut, the seeds germinate within the fruit while it still attached to the plant. In the presence of excessive moisture, rice grains have been seen germinating on the mother plant. After being separated from the fruit, the seeds continue to float on water. The germination starts within the seed and about 20 – 25 leaves come out in the plumule. The plumule pierces through the seed coat, leaving the cotyledons behind. The hypocotyl gets fleshy and ultimately the embryo or tiny plant gets detached from the cotyledons and floats independently on the surface of the water. Roots begin to come out in the tiny plant.

(f) Stilt roots: To support the plants growing in swampy soil, or in plants found on the edges of ponds, roots spring from the base of the stem and penetrate the soil obliquely. These are known as stilt roots. Such roots are found in Rhizophora. These roots give extra support to the plants and keep them steady in the ground. They also provide elasticity of the plant body.

Rajasthan Board RBSE Class 9 Science Chapter 7 Bio-Diversity

Bio-Diversity Rajasthan Board Solutions Additional Questions Solved

Multiple Choice Questions (MCQs)

Question 1.
Plants growing in saline water are called as-
(A) Mesophytes
(B) Halophytes
(C) Xerophytes
(D) Hydrophytes
Answer: B

Question 2.
In Volant or aerial animals, the fore­limbs are modified into-
(A) Wings
(B) Hind limbs
(C) Body
(D) Air chambers
Answer: A

Question 3.
In Whittaker’s classification, unicellular organisms are grouped under-
(A) Porifera
(B) Protozoa
(C) Protista
(D) Fungi
Answer: C

Question 4.
The general rule for writing a scientific names is-
(A) the generic name followed by a species name, that begins with a small letter
(B) the species name followed by a generic name
(C) the generic name beginning with a small letter
(D) all of the above
Answer: A

Question 5.
Pneumatophores are found in-
(A) Mesophyte plants
(B) Xerophyte plants
(C) Mangrove plants
(D) In all the above plants
Answer: C

Question 6.
Which one is a characteristic of xerophyte-
(A) Aerenchyma
(B) Large leaves
(C) Sunken stomata
(D) Poorly developed roots
Answer: C

Question 7.
Pneumatophores are found in-
(A) Mesophyte plants
(B) Xerophyte plants
(C) Mangrove plants
(D) In all the above plants
Answer: C

Question 8.
Which of the following plants has a flat stem-like leaf-
(A) Opuntia
(B) Hydrilla
(C) Vallisnaria
(D) Lotus
Answer: A

Question 9.
Which adaptation is not found in aquatic plants?
(A) Conducting tissue system is under developed
(B) Root system well developed
(C) Presence of arenchyma in plant organs
(D) Plants covered with mucilage
Answer: B

Question 10.
Plants of which division of plant kingdom cannot be differentiated into roots, stem and leaf
(A) Thallophyta
(B) Angiosperms
(C) Pteridophyta
(D) Gymnosperms
Answer: A

Question 11.
The connecting link between non-living and living is-
(A) Bacteria
(B) Virus
(C) Amoeba
(D) Euglena
Answer: B

Question 12.
The basic characteristic of chordates are-
(A) Presence of a notochord and a nerve cord.
(B) Presence of a nerve cord, notochord and gill left.
(C) Presence of a nerve cord and gill cleft.
(D) None of the above.
Answer: C

Question 13.
Tapeworm belongs to phylum-
(A) Porifera
(B) Annelida.
(C) Placental animal
(D) Corvus splendens
Answer: D

Question 14.
Birds are-
(A) Oviparous
(B) Viviparous
(C) Placental animal
(D) Having teeth in their mouth
Answer: A

Question 15.
Having teeth in their mouth What is the scientific name of national bird of India?
(A) Psittacula eupatra
(B) Passer domesticus
(C) Pavo cristatus
(D) Corvus splendens
Answer: C

Rajasthan Board RBSE Class 9 Science Chapter 7 Bio-Diversity

Bio-Diversity RBSE Rajasthan Board Solutions Very Short Answer Type Questions

Question 1.
According to binomial nomenclature, the scientific name of an organism must consist of two words. These are-
Answer
Genus and species.

Question 2.
What is characteristic of Angiosperm?
Answer
Seeds are formed in fruits.

Question 3.
What is classification?
Answer
Study of animal groups on the basis of similarities and differences is called classification.

Question 4.
Give two adaptations in desert plants.
Answer
1. To minimise the loss of water in leaves that all before summer or become very small in size and modify into spines, as in Opuntia.
2. The roots of desert plants are usually long, which go deep in search of water.

Question 5.
What are pneumatophores?
Answer
Plants (mangrove vegetation) in marshy places, develop a special type of geotropic roots. These roots are called pneumatophores, which possess breathing pores for gaseous exchange.

Question 6.
Classify the plants on the basis of available amount of water.
Answer
On the basis of availability of water plants, are classified into following classes-

1. Hydrophytes
2. Mesophytes
3. Xerophytes
4. Halophytes

Question 7.
Name the animals which have a four-chambered heart.
Answer
Animals of class Aves and Mammalia.

Question 8.
Name the-
(a) Largest existing mammal, and
(b) Largest mammal on land.
Answer
(a) The blue whale is the largest existing mammal.
(b) The elephant is the largest land mammal.

Question 9.
Which type of animals has no organs?
Answer
Unicellular animals have no organs, only loosely aggregated cells are found.

Question 10.
Name the respiratory organs in the following?
(a) Amoeba
(b) Tapeworm
(c) Crab
(d) Sepia
Answer
(a) Amoeba-Respiration is aerobic. It is through the general body surface.
(b) Tape worm-Respiration is anaerobic.
(c) Crab-Respiration through tracheal system.
(d) Sepia-Respiration through ctendiae.

Question 11.
Which class has the largest number of animals?
Answer
Insecta

Question 12.
Why is the scientific name of an organism unique?
Answer
The scientific name of an organism is unique because it can be used to identify an organism anywhere in the world.

Rajasthan Board RBSE Class 9 Science Chapter 7 Bio-Diversity

Bio-Diversity Solutions Short Answer Type Questions

Question 1.
Which organisms are called primitive and how are they different from so-called advanced organism’s?
Answer
The organisms having characteristics that came into existence earlier are referred to as “primitive” and the organisms having the characteristic that has come into existence, later on, are called “advanced”. For example, unicellular prokaryotic bacteria are primitive and multicellular, eukaryotic, mammalian are advanced. Likewise, algae are primitive plants and angiosperms are advanced plants. Fishes are primitive vertebrates and birds are advanced vertebrates.

Question 2.
What is the criterion for classification of organisms belonging to kingdom Monera or Protista?
Answer
The organisms which do not have a well-defined nucleus, membrane-bound cell organelles and multicellular body designs, are grouped under the kingdom Monera. The organisms which are unicellular and eukaryotic are grouped under the kingdom Protista.

Question 3.
Define Classification? Write the aims of classification?
Answer
Classification: The method of arranging organisms into groups, on the basis of similarities and differences is known as classification.
Aims of classification: Due to classification, there is no need to study each and everything, about all the living organisms.

1. Classification provides a picture of all plants and animals.
2. Classification gives an idea of similarities and differences between various groups ex-vertebrates and non-vertebrates.
3. It proves the idea of the common ancestor of all the living organism.
4. It shows the interrelationship among different groups of plants.

Question 4.
Why do we keep both, snake and turtle in the same class?
Answer
This is because of both snake and turtle:

• are cold-blooded
• have scales
• breathe through lungs, and
• do not need to lay their eggs in water.

Question 5.
Give three examples of the range of variation that you see in life forms around you.
Answer
Size: On one hand, there are micros­copic bacteria of a new micrometre in size and on the other hand, there are blue whales (about 30 metres) in animals, and redwood trees of California, about 100 metres tall.

Life span: Some pine trees live for thousands of years, while insects like mosquitoes live only for a few days.

Appearance: There are some species which are colourless and transparent also. On the other hand, there are various colourful birds, butterflies and other beautiful animals, and attractive plants, with coloured leaves and flowers.

Question 6.
What do you understand by Crypto- gamae and Phanerogamae? Explain.
Answer
Cryptogamae: The reproductive organs in the thallophytes, the bryophytes and the pteridophytes are hidden and are very conspicuous. External flowers or seeds are absent and they have naked embryos called spores. The plants in these three groups are, therefore, called ‘cryptogamae’.

Phanerogamae: Plant groups with well-developed reproductive organs, which produce seeds are called ‘phanerogamae’. Seeds consist of the embryo along with stored food which provides nutrition to the growing embryo. This group is classified into two sub-groups-gymnosperms and angiosperms, based on whether the seeds are naked or enclosed in fruits.

Question 7.
Explain the basis for grouping organisms into five kingdoms?
Answer
Whittaker based his scheme of classification on the following three levels of organisation:

• Prokaryotic versus Eukaryotic cell structure.
• Three different modes of nutrition- Photosynthesis, Absorption from the environment and Ingestion.
• Unicellular versus Multicellular organisation.

The five kingdom classification can be represented, in terms of cell structure as follows

Question 8.
Write the characteristics of phylum Annelida with examples.
Answer
Characteristics of Annelida are as follows:

1. Members of the phylum are bilaterally symmetrical and triploblastic. They have a true coelom.
2. Their body is long cylindrical and segmented.
3. Their body organisation is of organ system level.
4. The alimentary canal is complete.
5. The circulatory system is of open type.
6. Respiration takes place through skin.
   For Example Nereis, Pheretima (earthworm), Hirudinaria (Leech), etc.

Question 9.
Write any three concrete examples of such characteristics that are used for hierarchical classification.
Answer
Fungi, Plantae and Animalia are the three concrete examples that are used for hierarchical classification. These groups are formed on the basis of their cell structure, mode and source of nutrition and their body organisation.

Kingdom
Phylum (for animals)/Division (for plants)
Class
Order
Family
Genus
Species
Species is the smallest and basic unit of classification.

Question 10.
Name the invertebrate groups and their role in ecosystem?
Answer
Invertebrate groups are Porifera, Coelenterata, Platyhelminthes, Nematoda, Annelida, Arthropods, Mollusca and Echinodermata. These animals do not have a backbone and comprise of vast majority of species on earth.
Invertebrates play a vital role in keeping the ecosystem healthy in the following ways:

1. It helps to recycle dead plant and animal material.
2. It helps to pollinate flowers so that they produce seeds and fruits.
3. It turns the soil loose and distributes seeds.

4. 

   Rajasthan Board RBSE Class 9 Science Chapter 7 Bio-Diversity

   
   

Bio-Diversity Rajasthan Board Long Answer Type Questions

Question 1.
What are the major divisions in the Plantae? What is the basis of this division?
Answer
Kingdom Plantae includes the following five divisions:(1) Thallophyta (Algae)
(2) Bryophyta
(3) Pteridophyta
(4) Gymnospermae
(5) Angiospermae The first level of classification of plants is based on the presence and absence of well-differentiated distinct components in the body. Algae are separated from rest of the plants in
having simple and less differentiated thalloid plant body. The next level of classification is based on the presence and absence of vascular tissues. This character separates the Bryophyta from the rest of the plants. Further classification is based on the ability to bear seeds. Pteridophytes do not bear seeds. Finally, the groups are formed on the basis, whether seeds are naked or enclosed within fruits. The gymnosperms have naked seeds, whereas angiosperms bear seeds enclosed within the fruits.

• Further classification is based on the ability to bear seeds and whether the seeds are enclosed within fruits or not.
• Kingdom Plantae thus consists of Thallophyta, Bryophyta, Pteridophyta, Gymnosperms and Angiosperms.

Classification of Kingdom Plantae (Plants):

Question 2.
Define characteristics of Chordata and its classes?
Answer
Characteristics of Chordata:

• Animals of Chordata, have a notochord in some stage of their life.
• Animals have nerve chord on the mid­dorsal surface.
• They have pharangeal gill clefts, at some stage of life.
• The heart is present on the ventral surface
• Blood circulatory system is of closed type

This sub-kingdom is classified into five classes:
1. Class-Pisces: This class includes fishes and other aquatic animals. Fishes are aquatic and cold-blooded. Their body is spindle-shaped, divided into head, thorax and tail and their bodies are covered with scales. They have fins which help them in swimming. Endo-skeleton of fishes is cartilaginous or bony. Respiration takes place through gills. The heart is two-chambered.
Examples are: Dogfish, Rohu, Sea horse, Stingray etc.

2. Class-Amphibia: It includes many kinds of frogs. Animals can live both on land and in water. Their body is divided into head, thorax and abdomen. Their skin is smooth and wet, due to mucous. They have two pairs of legs, which help in swimming and locomotion. They respire through skin and lungs. Heart possesses two auricles and one ventricle.
Examples are: Frog, Toad, Tree frog, Salamander.

3. Class-Reptilia: It includes many kinds of snakes. Animals of this class crawl (creep), on the ground.Animals of this class respire through the lungs. Their body is divided into four parts – Heart, neck, thorax and tail and covered by endodermal scales. Their heart has two auricles and one incompletely divided ventricle. Animals of this class lay eggs.
Examples are: Tortoise, Lizard, Flying lizard, Viper, Chamaleon.

4. Class – Aves: This class includes a different kind of birds, that can fly in the air.
Their fore limbs are modified into wings, which help them in flying. Their body is boat shaped and stream­lined, divided into head, neck, thorax and tail, covered by feathers. There are no teeth in their jaws. They have horny beak. Their bones are hollow, with air-filled cavities. They have two pairs of pentadactyl (five digits) limb.
Examples are: Pigeon, Crow, Sparrow, Ostrich.

5. Class – Mammalia: It includes big animals, like Kangaroo, bat, monkey, cow and man. Developed mammary glands are found in females, mothers feed milk to young ones, through mammary glands. Their body is divided into head, neck, thorax and tail. Hairs are present on the body. Ear pinnae (External ear) is present. They are warm-blooded.

They respire through the lungs. The heart is completely four-chambered. Heart has 2 auricles and 2 ventricles. Most of the mammals are viviparous.
Examples are: Bat, Man, Mongoose, Rat, Lion, Tiger.

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