RBSE Class 9 Science Chapter 7: Biodiversity Important Textbook Questions and Solutions

Biodiversity refers to the diversity present in various life forms. It indicates the different living beings available in a particular habitat or specific area. The rich diversity of plants and animals is present on the earth in the regions lying between the Tropic of Cancer and the Tropic of Capricorn. Chapter 7 – Biodiversity also talks about topics such as groups of plants and animals, an adaptation of animals, according to their habitat, etc.

Students should keep these RBSE Class 9 Science solutions of Chapter 7 – Biodiversity handy. These solutions develop a strong conceptual base in students which plays a major role in the later stages to prepare successfully for the exams. We at BYJU’S provide detailed answers to RBSE Class 9 Science problems where the students can readily prepare all the concepts covered in the syllabus in a much better and effective way.

RBSE Class 9 Science Chapter 7: Objective Textbook Questions and Solutions

Q1. The most developed division of plants is:

(A) Bryophyta

(B) Angiosperm

(C) Gymnosperm

(D) Thallophyta

Answer: B

Q2. Viviparous germination of seeds take place in:

(A) Hydrophytes

(B) Mesophytes

(C) Xerophytes

(D) Halophytes

Answer: D

Q3. Presence of sunken stomata on leaves is an adaptation of:

(A) Xerophytes

(B) Halophytes

(C) Hydrophytes

(D) Mesophytes

Answer: A

Q4. Which plant group is known as vascular cryptogams?

(A) Pteridophyta

(B) Bryophyta

(C) Gymnosperms

(D) None of the above

Answer: A

Q5. An organisms of the class arthropoda is:

(A) Leech

(B) Tapeworm

(C) House fly

(D) Star-fish

Answer: C

Q6. The plant world has been classified into how many divisions

(A) Four

(B) Six

(C) Five

(D) Three

Answer: C

Q7. The scientific method used for nomenclature is known as

(A) Binomial Nomenclature

(B) Taxonomy

(C) Bryophyta

(D) Gymnosperms

Answer: A

Q8. Who is the “Father of binomial nomenclature”?

(A) Jerome Back

(B) Albertus Magnus

(C) Carolus Linnaeus

(D) Otto Brunfels

Answer: C

Q9. Halophytes are also known as the

(A) Natural vegetation

(B) Mangrove vegetation.

(C) Tropical vegetation

(D) Meditterean vegetation

Answer: B

Q10. How many parts are there in the scientific name of each organism

(A) Four

(B) Six

(C) Five

(D) Two

Answer: D

Q11. Scientific names are usually of which origin

(A) English Origin

(B) Greek Origin

(C) Latin Origin

(D) Persian Origin

Answer: C

Q12. What is the the scientific name of mango?

(A) Mangifera Indica.

(B) Malus domestica

(C) Citrus sinensis

(D) Musa x paradisiaca

Answer: A

Q13. Animal world has been classified into how many groups.

(A) Four

(B) Six

(C) Five

(D) Two

Answer: D

Q14. What is the connecting link between nonliving and living things?

(A) Virus

(B) Amoeba

(C) Euglena

(D) Bacteria

Answer: A

Q15. In which types of plants the ovules are not protected by the ovary and they remain open.

(A) Cryptogams

(B) Angiosperms

(C) Gymnosperms

(D) Porifera

Answer: C

RBSE Class 9 Science Chapter 7: Very Short Answer Type Questions and Solutions

Q16. Write the name of the Father of Binomial Nomenclature.

Answer: Carolus Linnaeus is the “Father of binomial nomenclature”.

Q17. To which animal class does the frog belong to?

Answer: Frog belong to the class of Amphibia

Q18. What is adaptation?

Answer: All the living beings (plants and animals) interact with their environment. Plants and animals are capable of surviving and reproducing in that environment because of their

special type of organs, characteristics (anatomical, physiological, behavioural) and activities. This is known as adaptation. Adaptations in living beings are generated because of the environment and also depends on the genetic factors.

Q19. Who proposed the five kingdom classification?

Answer: The five kingdom classification was proposed by Robert H Whittaker in 1969.

Q20. The blue-green algae (cyanobacteria) is a member of which division.

Answer: The blue-green algae (cyanobacteria) is a member of kingdom monera.

Q21. What is a lichen?

Answer: Lichen is a kind of primitive plant species that’s nothing more than strands of alga linked with roots and branches of a fungus that together absorb minerals from the ground and conduct photosynthesis.

Q22. Give two examples of gymnosperms.

Answer: The two examples of gymnosperms are Pinus and Cycas.

Q23. Name the organism in which respiration is by means of gills, lungs and skin.

Answer: Frog is the organism which respirates by means of gills, lungs and skin.

Q24. Name an egg-laying mammal.

Answer: Platypus is an egg-laying mammal.

Q25. In which habitat is the mangrove vegetation found?

Answer: Mangrove vegetation is found in saline soils or marshes.

RBSE Class 9 Science Chapter 7: Short Answer Type Questions and Solutions

Q26. Name the two specialities found in halophytes.

Answer: The two specialties found in Halophytes are:

Halophytes are the plants that grow in saline soils or marshes. In saline soil, soluble salts like sodium chloride, magnesium chloride and magnesium sulphate are present in abundance. The plants growing in marshy soils are known as Mangrove vegetation. Examples: Rhizophora, Salsola etc.

  • The roots of these plants do not go deep down into the soil therefore the ‘stem-roots’ develop and enter the marshy soil to provide extra support and stability.
  • The stems of these trees are spongy because of storage of chloride ions.

Q27. Write the adaptations of aquatic animals.

Answer: The adaptations of aquatic animals are:

  • The body of those animals is streamlined so they can swim easily in water.
  • These animals have fins or feathers, which help them in swimming and balancing their body.
  • Aquatic animals have gills for respiration and use the oxygen dissolved in water.
  • The bones of these animals are light in weight and are spongy. The neck is absent or is less developed.
  • They have scales or mucus glands on their body.
  • Salt excreting glands are present in animals living in marine habitat to remove the excess of salt from their body.
  • In amphibians like Salamander, respiration is both, by gills and by lungs. Example : Fish, Frog, Sea-turtle etc.

Q28. What are the special features of cold habitat?

Answer: The special features of cold habitat are:

The animals living in ice laden regions having low temperature are known as cold habitat animals. The cold habitats have very low temperature and the winds blowing in these regions are cold and dry. For most part of the year the land remains iceladen. The skin of animals living in such habitats is covered with dense hair. Their colour is white, in order to protect them from predators. Example : Polar – rabbit, Musk-ox

Q29. Write the characteristics of the animals of the class mammalia.

Answer: The animals of this class are found in all types of environments. They have mammary glands to nourish their young ones. Their heart is four chambered (two atrium and two

ventricles). The animals of this class are warm blooded and give birth to the young ones. However, there are a few exceptions : Echidna lay eggs; kangaroos give birth to very poorly developed young ones, which remain in a sac named marsupium until they develop completely. Example : Human beings , Duck – billed platypus, Kangaroo, Bat.

Q30. Write the characters of the animals of the class arthropoda.

Answer: The word arthropoda means arthro – jointed podas = appendages, i.e. these animals have jointed appendages. Maximum number of animals are present in this phylum. They are present at all the places on the earth. They are bilaterally symmetrical, triploblastic and coelomic animals. They have an open circulatory system. The body is segmented and is divisible

into head, thorax and abdomen. Class insecta is important in this phylum. Most insects have wings. Excretion in this class is by Malpighian tubules. Their body is covered with chitin and external skeleton. Examples : House-fly, Shrimp, Cockroach, Butterfly, Grass-hopper, Scorpion.

Q31: What is the function of mycorrhizae and coralloid roots in gymnosperms?

Answer: Gymnosperms are the plants in which the ovules are not protected by the ovary

and they remain open i.e. are not covered before or after fertilisation. They are also known as naked seeded plants.

The function of mycorrhizae and coralloid roots in gymnosperms are:

  • Gymnosperms are medium to tall trees or are shrubs. They have a tap root and in some plants of this group, there is symbiotic association between their roots and fungi. This association is known as the mycorrhizal association.
  • In some gymnosperms like Cycas, the nitrogen fixation cyanobacteria are associated with small special type of roots called the coralloid roots. Reproduction in gymnosperms is by means of spores and the fusion of antherozoids and the egg. Example: Cycas, Pinus.

Q32: Explain symbiosis in lichens.

Answer: Some species of fungi live in association with blue green algae (cyanobacteria). This type of mutually beneficial association is known as symbiosis. These symbionts are together known as lichens.

Q33. Why pteridophytes are known as the vascular cryptogams?

Answer: Pteridophytes, have a vascular system, i.e. xylem and phloem are present. Hence

they are also known as the vascular cryptogams . In the division pteridophyta reproduction is by means of spores and the union of sperms and eggs produced by the antheridia and archegonia, respectively. Example : Marsilia, Selaginella, Equisetum.

Q34. Describe the adaptations of xerophytes.

Answer: Xerophytes are recognised by their specific characteristics. These characteristics are as follows :

  • Xerophytes are present in habitats having scarcity of water, hence their roots are well developed and go deep down into the soil to absorb water.
  • Root hairs are present on roots for water absorption and root cap for protecting the growing root tip.
  • The stem of Xerophytic plants is woody and have multicellular hair on its surface. In some plants like Calotropis there is a layer of wax and silica present on the stem surface.
  • In some xerophytes the stem is green, succulent (stores water) and perform photosynthesis, as in aloe vera.
  • To prevent water loss from its surface, the leaves of xerophytic plants fall off during summer season. In some plants like Opuntia the leaves are modified into spines.
  • In some other xerophytic plants, a waxy coating is present on the leaf surface and the sunken stomata are present on the lower surface of the leaf to reduce transpiration.
  • A hard cover is present around the fruits and seeds of the xerophytic plants.
  • The osmotic concentration of the cells of xerophytic plants is high.

Q35. What are saprophytes?

Answer: Saprophytes absorb their nourishment from the dead and decaying organic matter. For example: Fungi are the heterotrophic, eukaryotic organisms and most of the fungi are parasitic.

Q36: Write two similarities between bryophytes and pteridophytes.

Answer: The bryophytes and pteridophytes have inconspicuous reproductive organs. They do not produce fruits and seeds. So, they are known as Cryptogams. Pteridophytes, however, have a vascular system, i.e. xylem and phloem are present. Hence, they are also known as vascular cryptogams.

Q37. What are monocots and dicots?

Answer: Monocot commonly refers to the flowering plants or angiosperms in which the seeds typically contain only one embryonic leaf or Cotyledon. Ginger, onions, wheat, and grass are the best examples of Monocotyledons

Dicot is generally referred to the flowering plants or angiosperms in which the seeds typically contain two embryonic leaves or cotyledon. All legumes, including beans, lentils, pea, and peanuts are the best examples of dicotyledons. There are around 1 lakh to 1.5 lakhs of different species of dicot plants.

Q38. Write two differences between invertebrates and vertebrates.

Answer: The two differences between invertebrates and vertebrates are:

  • Invertebrates can be simply identified as animals that don’t have a backbone. They are found almost everywhere, from the hottest deserts and the deepest water bodies to the darkest caves and tallest mountains. As stated before, invertebrates are the animals which mainly lack a skeletal system and other developed organs. This means most of them do not possess a rigid body structure and as a result, cannot grow very large. Anatomically, they consist of an open circulatory system where blood flows in an open cavity. Most invertebrates possess a simple respiratory system, with the most common form being gills and trachea.
  • Vertebrates are the most advanced of species in the animal kingdom. Members possess a well defined internal skeleton system, which includes a backbone. In humans, the spinal cord runs along the body between the caudal and cranial regions connecting to the nerve tissues. Vertebrates also have more complex and specialized organ systems when compared to invertebrates. Organ systems like the respiratory systems are quite complex, with many additional functions. Even the sensory organs are more advanced, which helps vertebrates adapt to their respective environment. Read more by clicking the highlighted link.

Q39. What is the function of pneumatophores in halophytes?

Answer: Halophytes are the plants that grow in saline soils or marshes. In saline soil, soluble salts like sodium chloride, magnesium chloride and magnesium sulphate are present in abundance.

Due to water-logging, marshy soils are deficient in oxygen and the normal regular roots do not get enough oxygen for respiration. Therefore, in these plants some branches of the root become

negatively geotropic and come out from the soil surface. Small pores are present on these aerial root which help the roots in oxygen uptake. These roots are known as Respiratory roots or Pneumatophores.

Q40. What is the function of assimilatory roots in water chest-nut?

Answer: In water chest-nut, the assimilatory root helps in the process of photosynthesis. These roots are green coloured for photosynthesis.

Q41. Write the adaptations of aves (aerial animals).

Answer: Animals that fly in air are known as avians or aerial animals. Following adaptations are found in these animals :

  • The bones of these animals are hollow and light.
  • Their forelimbs are modified into wings which help in flight.
  • Their eye-sight is more sharp as compared to that of the terrestrial animals.
  • Their body is covered with feathers which keep the body temperature constant.
  • Their tail assists in maintaining the balance of their body.
  • Body is cylindrical.

Example : Sparrow, Vulture, Parrot, Crow, Peacock etc.

RBSE Class 9 Science Chapter 7: Essay Type Questions and Solutions

Q42. Classify the plants on the basis of their habitat and describe the adaptations of each type.

Answer: Based on the water present in their environment and their need for water, plants are of

the following types :

  • Hydrophytes
  • Xerophytes
  • Mesophytes
  • Cryophytes
  • Halophytes

Hydrophytes: The plants which live in or on water or on water logged soil are known as hydrophytes. Examples : Vallisneria, Eichchornia, Sagittaria, Ranunculus, Hydrilla, Lotus, Water chestnut (singhara) etc.

Adaptations of hydrophytes:

  • The main function of the root system is to absorb water hence, because of abundant availability of water all around, the root system is less developed and water is absorbed from the plant surface.
  • In some plants like water- chestnut (Singhara or Trapa) the roots are green coloured for photosynthesis. They are known as the assimilatory roots.
  • Root hairs are absent. The root pockets replace the root hairs.
  • In some plants like Lemna, roots perform the act of balancing the plant body.
  • The stem is soft, thin and flexible in hydrophytes.
  • The leaves of the floating hydrophytes are broad while those of the submerged plants are dissected or ribbon shaped.
  • In hydrophytes pollination and dispersal of seeds and fruits is by means of water, hence their seeds and fruits are light in weight.
  • Air chambers are present in the internal structure of the leaves, stem and roots of the hydrophytes.
  • The osmotic concentration of the cells of hydrophytes is less i.e. the concentration of salts in the cytoplasm is less.
  • Hydrophytes lack well developed mechanical tissue and vascular tissue.

Xerophytes: Xerophytes are the plants that are found in dry habitat having scarcity of water. Example : Opuntia, Thor (Euphorbia), Cactus etc.

Adaptations of Xerophytes:

Xerophytes are recognised by their specific characteristics. These characteristics are as follows

  • Xerophytes are present in habitats having scarcity of water, hence their roots are well developed and go deep down into the soil to absorb water.
  • Root hairs are present on roots for water absorption and root cap for protecting the growing root tip.
  • The stem of Xerophytic plants is woody and have multicellular hair on its surface. In some plants like Calotropis there is a layer of wax and silica present on the stem surface.
  • In some xerophytes the stem is green, succulent (stores water) and perform photosynthesis, as in Aloe vera.
  • To prevent water loss from its surface, the leaves of xerophytic plants fall off during summer season. In some plants like Opuntia the leaves are modified into spines.
  • In some other xerophytic plants, a waxy coating is present on the leaf surface and the sunken stomata are present on the lower surface of the leaf to reduce transpiration.
  • A hard cover is present around the fruits and seeds of the xerophytic plants.
  • The osmotic concentration of the cells of xerophytic plants is high.

Halophytes: Halophytes are the plants that grow in saline soils or marshes.

Adaptations of Halophytes:

  • The roots of these plants do not go deep down into the soil therefore the ‘stem-roots’ develop and enter the marshy soil to provide extra support and stability.
  • Due to water-logging, marshy soils are deficient in oxygen and the normal regular roots do not get enough oxygen for respiration Therefore, in these plants some branches of the root become negatively geotropic and come out from the soil surface. Small pores are present on these aerial roots which help the roots in oxygen uptake. These roots are known as Respiratory roots Pneumatophores.
  • The stems of these trees are spongy because of storage of chloride ions.
  • The leaves are small, fleshy with a shining surface.
  • The seed in these plants start germinating while still within the fruit, attached to the parent plant.
  • The embryo grows out from the fruit in the form of a seedling made up of the radical and the hypocotyl. The seedling falls down vertically on the ground and the radical directly enters the marshy soil. This type of germination is known as the viviparous germination.

Cryophytes: The vegetation growing in colder regions and ice-laden soil are known as cryophytes. Example : Moss, Lichens, Salmon-berry.

Adaptations : In cold habitats, mostly the plants are herbs, mosses and lichens, which grow when the ice melts and complete their life cycle in very short duration i.e. these plants are short lived.

Salmon-berry is one of the many flowering plants which perennate under the snow and at the time of flowering, when the snow melts by the respiratory – heat produced, only the flower emerges on the surface of the snow.

Mesophytes: The plants that grow in habitats having moderate amount of water, moisture and temperature are known as mesophytes. In such habitats all the conditions are ideal for the growth and reproduction of the plants. The root system is well developed in these plants and bear root hairs and root cap. The stem is aerial, branched, thick and hard. Leaves are broad with stomata on both surface. Plants are well developed, with normal physiology. Examples : Garden-plants and crops.

Q43. Write the rules of the nomenclature of organisms, according to the binomial nomenclature system.

Answer: Each organism has a scientific name, by which it is known worldwide. This process is known as nomenclature.The scientific method use for nomenclature is known as binomial

nomenclature. Carolus Linnaeus proposed this method of nomenclature. According to this method of binomial nomenclature:

  • There are two parts in the scientific name of each organism – first is the name of the genus and the second is the species name.
  • Scientific names are usually of latin origin. They are written in italics. However, in case of hand-written names the two parts are underlined separately.
  • When writing in English the first alphabet of the genus name is capitalised while the name of species should start with small alphabet.

Example : The scientific name of mango is Mangifera indica.

Q44. Write the characteristic feature of the animals living in aquatic and desert habitats.

Answer: The animals which live in water i.e. aquatic habitat are known as aquatic animals. Some of these animals lie in marine water, some in fresh water and others are amphibious. These animals have characteristic features in order to adapt to their habitat. These features include :

  • The body of those animals is streamlined so they can swim easily in water.
  • These animals have fins or feathers, which help them in swimming and balancing their body.
  • Aquatic animals have gills for respiration and use the oxygen dissolved in water.
  • The bones of these animals are light in weight and are spongy. The neck is absent or is less developed.
  • They have scales or mucus glands on their body.
  • Salt excreting glands are present in animals living in marine habitat to remove the excess of salt from their body.
  • In amphibians like Salamander, respiration is both, by gills and by lungs. Example : Fish, Frog, Sea-turtle etc.

The animals which live on dry lands, i.e. habitat with scarcity of water are known as desert animals. These animals have characteristic features, which help them survive harsh conditions. These include :

  • The feet of these animals are adapted to walk, run and dig in the sandy deserts. For example, camels have cushioned feet.
  • The body-color of these animals is sandy i.e. brown like sand, so that they are protected against predators.
  • The faeces of these animals is solid and their urine is concentrated. Sweat glands are absent or less developed in their body.
  • On the body of some animals like Phrynosoma, scales are present to conserve water in the body.
  • The skin of some animals like moolak, is hygroscopic i.e. absorbs moisture from the surroundings.
  • There are water storing organs in these animals, which perform the function of water storage, example – Camel.
  • The nasal apertures are small and are covered by valves to prevent the entry of sand particles, examples – Camel.

Example : Camel, Phrynosoma, Wild-rat, Moolak etc

Q45. Describe the characteristic features of angiosperms and gymnosperms.

Answer: Gymnosperms are the plants in which the ovules are not protected by the ovary

and they remain open, i.e. are not covered before or after fertilisation. They are also known as the nakedseeded plants. Gymnosperms are medium to tall trees or are shrubs. They

have a tap root and in some plants of this group there is symbiotic association between their roots and fungi. This association is known as the mycorrhizal association. Example Pinus. In some gymnosperms like Cycas, nitrogen fixing cyanobacteria are associated with small special types of roots called the coralloid roots. Reproduction in gymnosperms is by means of spores and the fusion of antherozoids and the egg.

Example : Cycas, Pinus.

Angiosperms are the plants in which the seeds are ‘covered’ within the fruits. In other words, their seeds develop within the ovary which later on form the fruit. They are known as the flowering plants. The food in their seeds is either stored in the cotyledons or in the endosperms. On the basis of the number of cotyledons present in the seeds, they may be monocot (having single cotyledon) or dicot (having double cotyledon). Reproduction in these plants may be vegetative or sexual. In sexual reproduction there is fusion of the male gamete and the female gamete.

Example : Mustard, Mango, Banyan.

Q46. Write notes on the following:

(a) Mangrove vegetation

(b) Amphibians

(c) Salt secreting glands

(d) Lichens

(e) Viviparous germination

(f) Stem roots

Answer a: Mangrove vegetation – The plants growing in marshy soils are known as Mangrove vegetation. Examples: Rhizophora, Salsola etc.The roots of these plants do not go deep down into the soil therefore, the ‘stem-roots’ develop and enter the marshy soil to provide extra support and stability. Therefore, in these plants some branches of the root become negatively geotropic and come out from the soil surface. Small pores are present on these aerial root which help the roots in oxygen uptake. These roots are known as Respiratory roots Pneumatophores. The stems of these trees are spongy because of storage of chloride ions.

Answer b: Amphibians – The plants of this division are also known as the amphibians of the plant kingdom. They are known as amphibians because they can survive on land but depend on water for sexual reproduction. These plants lack the actual root, stem and leaves instead have the root-like, leaf-like and stem-like structures. They are connected with the

substratum by means of unicellular or multicellular rhizoids.

Liverworts and mosses are there in the bryophytes, in which asexual reproduction is by the fragmentation of the thallus or by special structures known as the gemma and the sexual reproduction occurs by the fusion of the antherozoid and egg produced by the antheridia and archegonia of the gametophyte respectively. Example : Marchantia, Funaria.

Answer c: Salt secreting glands – Salt excreting glands are present in animals living in marine habitat to remove the excess of salt from their body.

Answer d: Lichens – A lichen is not a single organism but a symbiosis among different organisms like fungus and a cyanobacterium or algae.

Lichens exist in one of the below-mentioned growth forms.

  • Crustose grows across the substrate.
  • Foliose are flat, leaf-like sheets of tissues and not bound closely.
  • Squamulose are closely clustered and lit flattened pebble units.
  • Fruticose are freely available standing branching tubes.

Answer e: Viviparous germination – The seed in halophytes plants start germinating while still within the fruit, attached to the parent plant. The embryo grows out from the fruit in the form of a seedling made up of the radical and the hypocotyl. The seedling falls down vertically on the ground and the radical directly enters the marshy soil. This type of germination is known as the viviparous germination.

Answer f: Stem roots – The roots of halophytes plants do not go deep down into the soil therefore, the ‘stem-roots’ develop and enter the marshy soil to provide extra support and stability.

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