4

Q1. Long hollow bones with interconnected air passages are characteristic of

• 1) Reptiles
• 2) Aves
• 3) All land vertebrates
• 4) Mammals

Solution

Long hollow bones with interconnected air passages are characteristic of Aves. These features help birds in easy flight.

Q2. Which one of the following groups of animals is bilaterally symmetrical and triploblastic?  

• 1) Coelenterates (Cnidarians)  
• 2) Aschelminthes (Roundworm)  
• 3) Ctenophores  
• 4) Sponges  

Solution

Aschelminthes (Roundworm) is triploblastic, and it is bilaterally symmetrical.  

Q3. Coelom is a cavity between the body wall and the alimentary canal and is lined by  

• 1) Ectoderm on both sides  
• 2) Ectoderm and endoderm  
• 3) Mesoderm on both sides  
• 4) Ectoderm and mesoderm  

Solution

The body wall and the alimentary canal both are lined by the mesoderm, which means the coelom body cavity is lined by the mesoderm on either side.  

Q4. Why do cartilaginous fish swim constantly?

Solution

An air bladder is absent in cartilaginous fish. Cartilaginous fish swim constantly in order to prevent themselves from sinking.

Q5. Which one of the following is common in silverfish, scorpion, dragonfly and prawn?  

• 1) Chitinous cuticle and two pairs of antennae  
• 2) Cephalothorax and tracheae  
• 3) Jointed appendages and chitinous exoskeleton  
• 4) Three pairs of legs and segmented body  

Solution

Jointed appendages and a chitinous exoskeleton are two features common in silverfish, scorpion, dragonfly and prawn. Features mentioned in the other options are also features observed in some of the arthropods.  

Q6. Name the excretory organ of Balanoglossus.

Solution

Proboscis gland

Q7. Which of the following group of animals maintains high and constant body temperature such as mammals?

• 1) Fish
• 2) Birds
• 3) Reptiles
• 4) Amphibians

Solution

Birds are homeothermic. Homeotherms are the animals which maintain high and constant body temperature independent of the temperature of the external environment.

Q8. Which of the following is the free swimming larva of coelenterates?  

• 1) Amphiblastula  
• 2) Planula  
• 3) Trochophore  
• 4) There is no larval stage in the life cycle of coelenterates  

Solution

In coelenterates, the zygote forms the planula larva which swims, settles and grows into a sessile polyp.  

Q9. Haemocoel is found in

• 1) Porifera
• 2) Coelenterata
• 3) Annelida
• 4) Arthropoda

Solution

In arthropods, the body cavity is filled with blood, and hence, it is known as haemocoel.

Q10. Draw a well-labelled diagram of cnidoblast.  

Solution

   

Q11. Find the odd example  

• 1) Sea cucumber  
• 2) Sea urchin  
• 3) Sea fly  
• 4) Sea fan  

Solution

Sea fan is a sessile colonial cnidarian, while sea cucumber and sea urchin are echinoderms.  

Q12. Pseudocoelomate among these is  

• 1) Mollusca  
• 2) Aschelminthes  
• 3) Porifera  
• 4) Annelida  

Solution

Aschelminthes is a pseudocoelomate because the gut is not lined by the mesoderm.  

Q13. A mismatch in the following is  

• 1) Cartilaginous fish - shark  
• 2) Hydra - cnidarian  
• 3) Pheretima - parapodia  
• 4) Odd-toed - horse  

Solution

Setae are present in Pheretima prosthuma (earthworm) for locomotion. Parapodia are present in Nereis.   

Q14. In contrast to Annelids, the Platyhelminthes show

• 1) Presence of pseudocoel
• 2) Absence of body cavity
• 3) Radial symmetry
• 4) Bilateral symmetry

Solution

Annelids are coelomates, while platyhelminthes are acoelomates, i.e. the body cavity is absent.

Q15. Dengue is transmitted by

• 1) Male Anopheles
• 2) Aedes
• 3) Culex
• 4) Female Anopheles

Solution

Aedes is the mosquito which transmits dengue.

Q16. Gambusia is a

• 1) Yellow fever mosquito
• 2) Pest of fishes
• 3) Parasitic fish
• 4) Predator of mosquito larvae

Solution

Gambusia feeds on larvae of insects. They also thrive in shallow and stagnant waters. Therefore, they are used as a mosquito control agent.

Q17. Which is the only phylum in kingdom Animalia without any nerve cell?  

• 1) Nematoda  
• 2) Porifera  
• 3) Coelenterata  
• 4) Annelida  

Solution

Animals which belong to phylum Porifera are the only animals which do not have a nervous system. They do not give any visible response to stimuli.  

Q18. In which one of the following sets of animals do all the four give birth to young ones?

• 1) Platypus, Penguin, Bat, Hippopotamus
• 2) Shrew, Bat Cat, Kiwi
• 3) Kangaroo, Hedgehog, Dolphin, Loris
• 4) Lion, Bat, Whale, Ostrich

Solution

Kangaroo, Hedgehog, Dolphin, Loris are mammals. Viviparity is the characteristic feature of mammals. However, platypus, though a mammal, lays eggs.

Q19. Which one of the following is not a living fossil?

• 1) Peripatus
• 2) Archaeopteryx
• 3) Sphenodon
• 4) King crab

Solution

A living fossil is an organism which has remained unchanged in structure and function over a long period of time. Archaeopteryx is an extinct ancient or lizard bird which shows evolutionary connections between reptiles and birds. King crab (Arthropoda), sphenodon (Reptilia) and peripatus (an invertebrate) are examples of living fossils.

Q20. What is radula? State its function.

Solution

Radula is a file-like rasping organ present in the mouth of certain molluscs. It is used for feeding.

Q21. Digestion is intracellular in 

• 1) Platyhelminthes
• 2) Cnidaria
• 3) Both A and B
• 4) Porifera

Solution

Sponges achieve the goal of digestion through intracellular digestion where food particles are digested. 

Q22. Pseudocoelom occurs in

• 1) Fasciola hepatica
• 2) Ascaris
• 3) Taenia solium
• 4) Planaria

Solution

In pseudocoelomates, the body cavity is not lined by the mesoderm, but it is scattered in pouches between the ectoderm and the endoderm.

Q23. Insects have

• 1) 3 pairs of legs
• 2) 2 pairs of legs
• 3) 1 pair of legs
• 4) 4 pairs of legs

Solution

Insects (Class Insecta) belong to the phylum Arthropoda. They have 3 pairs of jointed legs.

Q24. Which of the following is not a character of Taenia solium?  

• 1) Proglottid  
• 2) Strobila  
• 3) Apolysis  
• 4) Metamerism  

Solution

Metamerism is a kind of segmentation in which the body is segmented externally and internally. The external segments of the body correspond with the internal segments. Taenia solium exhibits pseudometamerism.   

Q25. Which of the following pairs are correctly matched?   Sr. No.  Animals  Morphological features  (i)  Crocodile  4-chambered heart  (ii)  Sea urchin   Parapodia  (iii)  Obelia  Metagenesis  (iv)  Lemur  Thecodont   

• 1) Only (i) and (ii)
• 2) (ii), (iii) and (iv)
• 3) Only (i) and (iv)
• 4) (i), (iii) and (iv)

Solution

Crocodile is a reptile and it has a four-chambered heart. Obelia belongs to the phylum Cnidaria. The cnidarian life cycle shows alteration of generations between polyps and medusae. This is called metagenesis. Lemur is a mammal. All mammals are thecodonts, i.e. teeth are embedded in sockets in the jaws.

Q26. Bioluminescence is commonly seen in 

• 1) Porifera
• 2) Ctenophora
• 3) Annelida
• 4) Echinodermata

Solution

Bioluminescence is the production of light with very little heat by a chemical reaction within an organism. This is seen in ctenophores such as comb jellies. 

Q27. Draw diagrams representing the germinal layers found in diploblastic and triploblastic animals.  

Solution

         

Q28. Which of the following characters are present in class Crustacea?  

• 1) Cephalothorax, gills and appendages  
• 2) Head and thorax, gills and appendages  
• 3) Cephalothorax, book gills and appendages  
• 4) Head and thorax, book gills and appendages  

Solution

Organisms which belong to class Crustacea show the presence of a cephalothorax (head and thoracic regions are fused), gills as respiratory organs and jointed appendages. Animals such as crabs, lobsters and prawns belong to class Crustacea.  

Q29. Animal without the larval stage or metamorphosis is

• 1) Musca domestica
• 2) Asterias
• 3) Pheretima posthuma
• 4) Butterfly

Solution

Pheretima posthuma, the common name is earthworm, does not have any larval stage in its life cycle.

Q30. Order Primata contains

• 1) Horse and zebra
• 2) Bat and flying fox
• 3) Monkey and man
• 4) Shrew and hedgehog

Solution

Monkey and man belong to order Primata.

Q31. Poison gland of a snake is the modified  

• 1) Lingual gland  
• 2) Sublingual gland  
• 3) Maxillary gland  
• 4) Parotid gland  

Solution

The parotid glands are modified into poison glands in snakes.  

Q32. Name the cnidarian which exhibits alteration of generation.  

Solution

 Obelia exists in both forms, i.e. polyp and medusa, and it shows alteration of generation.  

Q33. Name the reptile which has a four-chambered heart.

Solution

Crocodile

Q34. The simplest type of canal system in Porifera is the 

• 1) Ascon type
• 2) Radial type
• 3) Sycon type
• 4) Leucon type

Solution

The simplest type of canal system in Porifera is the ascon type. 

Q35. Which of the following is not clearly noticeable in birds?

• 1) Pectoral girdle
• 2) Hind limb
• 3) Fore limb
• 4) Pelvic girdle

Solution

In birds, the forelimbs are modified into wings for flight.

Q36. A special character of coelenterates is 

• 1) Polymorphism
• 2) Nematocysts
• 3) Flame cells
• 4) Hermaphroditism

Solution

The characteristic feature of coelenterates is the presence of nematocysts or stinging cells. Nematocysts help in food capture, defence and attachment. 

Q37. In contrast to the Annelids, the Platyhelminthes show:  

• 1) Bilateral symmetry  
• 2) Radial symmetry  
• 3) Presence of pseudocoel  
• 4) Absence of body cavity  

Solution

In annelids, the body cavity is lined by the mesoderm and they are coelomates. In case of Platyhelminthes, the body cavity is not lined by the mesoderm, but the mesoderm is present in pouches between the ectoderm and the endoderm. Hence, they are called pseudocoelomates.  

Q38. Leech secretes which of the following anticoagulants?  

• 1) Histamine  
• 2) Serotonin  
• 3) Hirudin  
• 4) Heparin  

Solution

Leech secretes hirudin (anticoagulant) which prevents the clotting of host’s blood at the time of feeding.  

Q39. Biradial symmetry and lack of cnidoblasts are the characteristics of

• 1) Starfish and sea anemone
• 2) Ctenoplana and Beroe
• 3) Hydra and starfish
• 4) Aurelia and Paramecium

Solution

Ctenoplana and Beroe belong to the phylum Ctenophora. Ctenophores possess biradial symmetry, but they do not have cnidoblasts. Hydra, sea anemone and Aurelia belong to the phyla Cnidaria or Coelenterata whose special feature is the presence of cnidoblast cells.

Q40. Metameric segmentation is the main feature of  

• 1) Arthropoda  
• 2) Annelida  
• 3) Echinodermata  
• 4) Coelenterata  

Solution

Metameric segmentation is true segmentation in which external segmentation corresponds to the internal segmentation and the body is divided into a number of segments.  

Q41. State the function of comb plates in comb jellies.

Solution

Comb plates found in comb jellies help in locomotion.

Q42. Flame cells are the excretory organs in  

• 1) Cockroach  
• 2) Hydrilla  
• 3) Planaria  
• 4) Hydra  

Solution

Flame cells are found only in organisms which belong to the phylum Platyhelminthes (Planaria belongs to class Turbellaria). A flame cell is a hollow cell containing a tuft of cilia or flagella. This cell beats incessantly and resembles a flickering cell; hence, it is called a flame cell. Flame cells play a role in excretion and osmoregulation.  

Q43. Write the scientific name of the bath sponge.

Solution

Euspongia 

Q44. What is medusa? Give any one example.

Solution

The medusa is an umbrella-shaped, free swimming form of Cnidaria which reproduces sexually. Example: Aurelia

Q45. State any two phyla of non-chordates which have radial symmetry as their characteristic feature.

Solution

Animals from the phyla Cnidaria and Echinodermata show radial symmetry.

Q46. Which of the following have a notochord throughout life?

• 1) Fish
• 2) Amphioxus
• 3) Birds
• 4) Snake

Solution

Amphioxus belongs to the phylum Chordata (subphylum Cephalochordata). In amphioxus, the notochord persists throughout life. In chordates which belong to the subphylum Vertebrata, the notochord develops into the vertebral column during embryonic development.

Q47. Metameric segmentation is the characteristic of  

• 1) Annelida and Arthropoda  
• 2) Echinodennata and Annelida  
• 3) Platyhelminthes and Arthropoda  
• 4) Mollusca and Chordata  

Solution

Metameric segmentation is true segmentation in which external segmentation corresponds to the internal segmentation and the body is divided into a number of segments. Animals which belong to phyla Annelida and Arthropoda exhibit metameric segmentation.  

Q48. State the features of phylum Mollusca.

Solution

Features of phylum Mollusca  Molluscs have an organ-system level of organisation. Body bears a calcareous shell and is unsegmented with distinct head, muscular foot and visceral hump. A mantle cavity is present between the visceral hump and the mantle. Molluscs are triploblastic and bilaterally symmetrical. They are coelomates. They are oviparous and show direct development.

Q49. What is the most unique characteristic of mammals?

Solution

The presence of milk-producing mammary glands is the most unique characteristic of mammals.

Q50. Bilateral symmetry, metameric segmentation, coelom and open circulatory are features of

• 1) Echinodermata
• 2) Arthropoda
• 3) Annelida
• 4) Mollusca

Solution

Bilateral symmetry, metameric segmentation, coelom and open circulatory are features of Arthropoda.

Q51. Sea snakes are  

• 1) Ovoviviparous  
• 2) Viviparous  
• 3) Oviparous  
• 4) Parthenogenetic  

Solution

Sea snakes belong to class Reptilia. Most of the reptiles are oviparous, but some reptiles exhibit ovoviviparity or viviparity. Oviparous animals lay eggs, viviparous animals give birth to young ones, while in ovoviviparous animals, the embryo develops in the egg inside the mother’s body until it is ready to hatch.  

Q52. Which one of the following characters is not typical of the class Mammalia?  

• 1) Thecodont dentition  
• 2) Seven cervical vertebrae  
• 3) Ten pairs of cranial nerves  
• 4) Alveolar lungs  

Solution

Twelve pairs of cranial nerves are present in mammals. Thecodont dentition, alveolar lungs and seven cervical vertebrae are typical features of class Mammalia.  

Q53. Define metamerism.

Solution

Metamerism is a kind of segmentation in which the body is segmented externally and internally. The external segments of the body correspond to the internal segments.

Q54. In which triploblastic animal, coelom is absent?

• 1) Annelids
• 2) Platyhelminthes
• 3) Arthropods
• 4) Aschelminthes

Solution

In Platyhelminthes, endoderm, ectoderm and mesoderm are present. However, the mesoderm is present patched between the endoderm and the ectoderm, and it does not line the gut.

Q55. Distinguish between Porifera and Ctenophora

Solution

Porifera Ctenophora Animals show cellular level of organisation. Animals show tissue level of organisation. They are asymmetrical. They are radially symmetrical. Digestion is intracellular. Digestion is extracellular and intracellular. Fertilisation is internal. Fertilisation is external. Example: Sycon Example: Pleurobrachia  

Q56. Which of the following is a pseudocoelomate?

• 1) Flatworm
• 2) Roundworm
• 3) Tapeworm
• 4) Hydatid worm

Solution

Roundworm belongs to phylum Aschelminthes, and it is a pseudocoelomate. The gut is not lined by the mesoderm.

Q57. Which two sub-phyla are collectively referred to as protochordates?

Solution

Cephalochordata and Urochordata are collectively referred to as protochordates.

Q58. Among the following, colonial insects are  

• 1) White ants  
• 2) Bed bug  
• 3) Locusts  
• 4) Mosquitoes  

Solution

White ants are colonial insects.  

Q59. What is common between parrot, platypus and kangaroo?  

• 1) Functional post-anal tail  
• 2) Homoiothermy  
• 3) Toothless jaws  
• 4) Oviparity  

Solution

Parrot, platypus and kangaroo are mammals. Homoiothermy is the common feature seen in these three animals. Homoiothermy is the phenomenon in which animals maintain constant, high body temperature irrespective of the temperature of the external environment.  

Q60. In which of the following organisms, self-fertilisation is seen?  

• 1) Earthworm  
• 2) Roundworm  
• 3) Liver fluke  
• 4) Fish  

Solution

Liver fluke is hermaphrodite, and it shows self-fertilisation as well as cross-fertilisation.  

Q61. Scorpion belongs to a class to which one of the following also belongs

• 1) Ticks
• 2) Cockroach
• 3) Crab
• 4) Barnacles

Solution

Scorpions and ticks belong to class Arachnida (Phylum Arthropoda).

Q62. Ichthyophis is a  

• 1) Limbless reptile  
• 2) Limbless amphibian  
• 3) Limbless mammal  
• 4) Worm  

Solution

Ichthyophis is a burrowing amphibian. Because of their burrowing habit, they have lost their limbs and even their eyes are degenerated.  

Q63. Which of the following groups of structures/organs have similar function?  

• 1) Incisors of rat, gizzard (proventriculus) of cockroach and tube feet of starfish  
• 2) Nephridia in earthworm, Malpighian tubules in cockroach and urinary tubules in rat  
• 3) Antennae in cockroach, tympanum of frog and clitellum of earthworm  
• 4) Typhlosole in earthworm, intestinal villi in rat and contractile vacuole in Amoeba  

Solution

Nephridia in earthworm, Malpighian tubules in cockroach and urinary tubules in rat play a role in excretion and osmoregulation.  

Q64. The silverfish Lepisma is  

• 1) Echinoderm  
• 2) Mammal  
• 3) Insect/arthropod  
• 4) Fish  

Solution

Lepisma (silverfish) belongs to the insect class under phylum Arthropoda.  

Q65. Enlist the characteristic features of Petromyzon as representative of class Cyclostomata.

Solution

Characteristic features of Petromyzon: It is an ectoparasite. The body is elongated bearing 6-15 pairs of gills. The mouth is circular, sucking type with jaws. Cranium and vertebral column are cartilaginous. It has a closed circulatory system. Although it is marine, it migrates to freshwater for spawning.

Q66. What is a true coelom?

Solution

A true coelom is one which is completely lined by amesoderm.

Q67. Ascaris is characterised by  

• 1) Presence of neither true coelom nor metamerism  
• 2) Presence of true coelom but absence of metamerism  
• 3) Absence of true coelom and presence of metamerism  
• 4) Presence of true coelom and metamerism  

Solution

Ascaris belongs to phylum Aschelminthes. It is a pseudocoelomate and does not show metameric segmentation.  

Q68. Define notochord.

Solution

A notochord is a mesodermally derived rod-like structure formed on the dorsal side during embryonic development.

Q69. Wuchereria is found in

• 1) Lymph nodes
• 2) Lungs
• 3) Eye
• 4) Gonads

Solution

Wuchereria bancrofti infects lymph vessels and lymph nodes. It often obstructs lymph flow causing elephantiasis, i.e. swelling of the affected region.

Q70. Classification of Porifera is based on 

• 1) Symmetry
• 2) Branching
• 3) Reproduction
• 4) Spicules

Solution

Classification of Porifera is based on the skeleton, i.e. spicules. 

Q71. The colour of the body in earthworm is brown due to the presence of

• 1) Haemoglobin
• 2) Haemocyanin
• 3) Blood
• 4) Porphyrin

Solution

Porphyrin is a pigment which protects the earthworm from harmful ultraviolet radiations. It also imparts a brown colour to the earthworm.

Q72. What are amniotes?

Solution

Reptiles, birds and mammals that form special embryonic membranes during development are called amniotes. The special embryonic membranes include amnion, chorion, allantois and yolk sac.

Q73. Given below are the pairs of animals and phylum which they belong to. Which out of these is not a matching pair and why?     Bombyx - Arthropoda     Loligo - Mollusca     Asterias - Mollusca     Saccoglossus - Hemichordata  

Solution

      The pair Asterias - Mollusca is not matching.     Asteria, i.e. star fish, shows the presence of a water vascular system, the adult is radially symmetrical and larvae are bilaterally symmetrical. Hence, Asterias is an echinoderm.  

Q74. Ambulacral grooves are absent in the class  

• 1) None of these  
• 2) Ophiuroidea  
• 3) Asteroidea  
• 4) Crinoidea  

Solution

Ambulacral grooves are deep grooves present on the oral surface in echinoderms. These grooves extend from the mouth to the end of each arm. Each groove bears rows of tube feet. In class Ophiuroidea, the ambulacral grooves are absent. Example: Sea urchin  

Q75. Choose the correct pair:

• 1) Coelomates - Aschelminthes
• 2) Triploblastic - Sponges
• 3) Radial symmetry - Coelenterates
• 4) Metagenesis - Echinoderms
• 5) Metamerism - Mollusca

Solution

Coelenterates exhibit radial symmetry. Example: Aurelia

Q76. Which one of the following is a matching set of a phylum and its three examples?  

• 1) Porifera - Spongilla, Euplectella, Pennatula  
• 2) Platyhelminthes - Planaria, Schistosoma, Enterobius  
• 3) Cnidaria - Bonellia, Physalia, Aurelia  
• 4) Mollusca - Loligo, Teredo, Octopus  

Solution

Loligo (Class - Cephalopoda), Teredo (Class - Bivalvia) and Octopus (Class - Cephalopoda) fall under kingdom Mollusca.  

Q77. Draw a well-labelled diagram of Balanoglossus.  

Solution

   

Q78. Statement A: All metatherians are placental mammals.     Statement B: All placental mammals have menstrual cycle.  

• 1) Statement B is true and statement A is false.  
• 2) Both the statements A and B are true.  
• 3) Both the statements A and B are false.  
• 4) Statement A is true and statement B is false.  

Solution

In metatherians, a true placenta, i.e. allantoic placenta, is absent. All placental females have a uterine lining which builds at the time of accepting the fertilised zygote and it sheds off if fertilisation does not occur. This is called menstrual cycle.  

Q79. Provide an appropriate technical term in the space provided: (a) Property of living organisms to emit light  (b) Free-floating form of Cnidaria (c) Stinging organ of jelly fish    (d) Central cavity in sponges

Solution

The property of living organisms to emit light: Bioluminescence Free-floating form of Cnidaria: Medusa Stinging organ of jelly fish: Cnidoblast Central cavity in sponges: Spongocoel

Q80. The extinct bird Dodo belonged to  

• 1) India  
• 2) Australia  
• 3) Indonesia  
• 4) Mauritius  

Solution

The dodo was found in Mauritius. It became extinct due to hunting by settlers and predation of nests by introduced pigs.  

Q81. In molluscs, the eye is present over a stalk called  

• 1) Osphradium  
• 2) Ostracum  
• 3) Operculum  
• 4) Ommatophores  

Solution

Ommatophores  

Q82. Which of the following organisms have a loose mantle over their body?  

• 1) Platyhelminthes  
• 2) Molluscs  
• 3) Mammals  
• 4) Echinoderms  

Solution

The mantle is a thick, muscular fold of the body wall. It protects the internal body organs.  

Q83. Describe the skeleton of poriferans in one line.  

Solution

The skeleton of poriferans is made up of spicules or spongin fibres.  

Q84. Name the compound present in the skeleton of corals.

Solution

Calcium carbonate is found in the skeleton of corals.

Q85. The type of canal system found in Leucosolenia is

• 1) Leucon type
• 2) Scon type
• 3) Aphodal type
• 4) Ascon type

Solution

In Leucosolenia, the Ascon type of canal system is found. The Ascon system is the simplest type of canal system in which ostia directly open into the spongocoel. The spongocoel is lined by choanocytes, and it opens to the outside by an opening called osculum which is present at the distal free end of the sponge body.

Q86. Distinguish between polyps and medusae.  

Solution

Polyps     Medusae     1. Polyps are sessile and resemble a cylindrical stalk with mouth and tentacles.     1. Medusae are free-swimming, umbrella-like structures with tentacles.     2. They reproduce asexually by budding.     2. Medusae reproduce sexually by releasing gametes in water.     3. Example: Hydra     3. Example: Jelly fish        

Q87. Daphnia is commonly known as  

• 1) fairy shrimp  
• 2) clam shrimp  
• 3) water fleas  
• 4) tadpole shrimp  

Solution

Daphnia are called water fleas because their swimming style resembles the movement of fleas.  

Q88. Name the flatworm which has high regeneration capacity.

Solution

Planaria possesses high regeneration capacity.

Q89. Distinguish between phyla Porifera and Cnidaria.

Solution

Porifera Cnidaria 1. Animals are asymmetrical. 1. Animals are radially symmetrical. 2. Water canal system is well-developed. 2. Water canal system is absent. 3. They show the presence of choanocytes or collar cells. 3. They show the presence of cnidoblasts or nematocytes. 4. They have a skeleton of spicules or sponging fibres. 4. Only some cnidarians show the presence a skeleton which is made of calcium carbonate. 5. They show cellular level of organisation. 5. They show tissue level of organisation. 6. Examples: Sycon, Spongilla 6. Examples: Obelia, Adamsia  

Q90. Notochord is present in

• 1) Few chordates
• 2) Few vertebrates
• 3) All vertebrates
• 4) All chordates

Solution

Dorsal, rod-like notochord is the primary feature of all chordates. Based on this feature, all animals which show the presence of notochord are grouped under the phylum Chordata.

Q91. Spermathecae in earthworm is  

• 1) For storage of sperm obtained from the male worm during copulation and used in the future  
• 2) Both 1 and 2 above  
• 3) For producing sperm  
• 4) None of these  

Solution

Four pairs of spermathecae are present in the 6^th, 7^th, 8^th and 9^th segments. They open on the ventral side. Spermathecae receive and store sperms during copulation.  

Q92. Write important characteristic features of phylum Porifera.  

Solution

Characteristic features of phylum Porifera:     Poriferans are marine animals.   They are asymmetrical.   They exhibit cellular level of organisation.   Sponges are hermaphrodite, i.e. eggs and sperms are produced by the same individual.   Sponges show the presence of a water canal system which helps in reproduction and gathering of food from the surrounding water, gas exchange and excretion.   Skeleton is made of spongin fibres or spicules.   Fertilisation in sponges is internal.   Digestion is intracellular.   Special cells called choanocytes are present on the internal lining of the spongocoel.   (Write any 5)  

Q93. Write the scientific name of the freshwater sponge.

Solution

Spongilla 

Q94. Which animals have larval stages?  

• 1) Housefly and butterfly  
• 2) Grasshopper and dragonfly  
• 3) Cockroach and housefly  
• 4) Cockroach and honeybee  

Solution

The larva of housefly is called maggot, and the larva of butterfly is called caterpillar.  

Q95. Write the characteristic features of phylum Cnidaria which prove that phylum Cnidaria is advanced over Porifera.  

Solution

Following characteristic features show that phylum Cnidaria is advanced over phylum Porifera.     Cnidarians exhibit tissue level of organisation, while poriferans show cellular level of organisation.   In cnidarians, extracellular digestion is observed which is absent in poriferans.   Nerve cells and sensory cells are present in cnidarians, but they are absent in poriferans.

Q96. Explain metagenesis in cnidarians.

Solution

Some cnidarians exist in polyp and medusa forms. Such cnidarians show metagenesis. It is the phenomenon of alternation of generations in which polyps produce medusae asexually and medusae produce polyps sexually. Metagenesis is observed in Obelia.

Q97. What are parapodia? State their function.  

Solution

Parapodia are lateral appendages. They help in locomotion. Example: Nereis  

Q98. Distinguish between diploblastic and triploblastic animals.  

Solution

Diploblastic Animals     Triploblastic Animals     The cells are arranged in two embryonic layers—external ectoderm and internal endoderm.   The cells are arranged in two embryonic layers—external ectoderm, middle layer of mesoderm and internal endoderm.   Mesoglea is present between the ectoderm and the endoderm.   Mesoglea is absent. Instead, the mesoderm is present between the endoderm and the ectoderm.   Examples: Cnidaria and Ctenophora   Examples: Platyhelminthes to Chordata      

Q99. What type of digestion is seen in the members of phylum Porifera?

Solution

Intracellular digestion is seen in the members of phylum Porifera.

Q100. State any two examples of phylum Coelenterata.

Solution

Two examples of phylum Coelenterata: Hydra and Obelia.

Q101. Cnidoblasts help in 

• 1) Anchorage
• 2) Capture of prey
• 3) All of the above
• 4) Defence

Solution

Cnidoblasts are used for anchorage, defence and for the capture of prey. 

Q102. Match the incorrect pair.

• 1) Aedes - yellow fever
• 2) Culex - malaria
• 3) Pediculus - typhus
• 4) Xenopsylla - plague

Solution

Culex mosquito spreads filariasis or elephantiasis. Anopheles mosquito spreads malaria.

Q103. Distinguish between class Chondrichthyes and Osteichthyes.

Solution

Chondrichthyes Osteichthyes 1) They possess a cartilaginous endoskeleton. 1) They possess a bony endoskeleton. 2) The mouth is located ventrally. 2) The mouth is located terminally. 3) Gills are without  operculum. 3) Gills are covered with operculum. 4) Air bladder is absent. 4) Air bladder is present. 5) Fertilisation is internal. 5) Fertilisation is external. 6) Skin is covered with placoid scales. 6) Skin is covered with cycloid scales.  

Q104. Define bioluminescence.

Solution

Bioluminescence is the property of living organisms to emit light.

Q105. Describe the water canal system of sponges.

Solution

The water canal system is a peculiar feature of sponges. The body wall bears many minute pores called ostia. On the anterior side of the body, there is a large single opening called the osculum. Water enters the spongocoel through ostia and leaves the body through the osculum. This water is used by sponges to gather food, for gas exchange, excretion etc.

Q106. Write any two examples of phylum Platyhelminthes.

Solution

Examples of phylum Platyhelminthes: Taenia, Fasciola hepatica

Q107. What are diploblastic animals?

Solution

Animals in which the cells are arranged in two embryonic layers—external ectoderm and internal endoderm—are called diploblastic animals.

Q108. Describe symmetry in animals.

Solution

Animals can be categorised on the basis of their symmetry pattern. They can be categorised as follows: Asymmetrical animals Bilaterally symmetrical animals Radially symmetrical animals Asymmetrical animals: The body of these animals cannot be divided into two identical halves along any plane passing through the centre. Example: Sponges Bilaterally symmetrical animals: The body can be divided into identical left and right halves in only one plane. Examples: Arthropods, annelids Radially symmetrical animals: The body of these animals can be divided into equal halves by any plane passing through the central axis of the body. Example: Adult echinoderms

Q109. How are the animals of Arthropoda different from those of Mollusca?

Solution

Arthropoda Mollusca 1) Body is segmented and divided into head, thorax and abdomen.   1) Body is soft, unsegmented and divided into head, muscular foot and visceral mass. 2) Excretion is by Malpighian tubules. 2) Excretion is by gills or kidneys. 3) Respiration is by gills, tracheal tubes or book lungs. 3) Respiration is by gills. 4) Arthropods have chitinous exoskeleton. 4) Molluscs have calcareous exoskeleton.  

Q110. Write characteristic features of phylum Platyhelminthes.

Solution

Characteristic features of phylum Platyhelminthes: They are bilaterally symmetrical. They do not have any body cavity; hence, they are acoelomates. They are triploblastic animals. Excretion and osmoregulation occur by specialised cells called flame cells. Fertilisation is internal. (Write any 3 or 4)

Q111. Name the cells which line the spongocoel in Sycon.  

Solution

Pinacocytes line the spongocoel in Sycon.  

Q112. Write any two examples of phylum Hemichordata.

Solution

Examples of phylum hemichordate: Balanoglossus, Saccoglossus

Q113. How is a tapeworm attached to the host's intestine?

Solution

Tapeworm attaches itself with hooks that penetrate the gut wall and with suckers which stick to the gut wall by vacuum principle.

Q114. Name two cnidarians which are polyps.

Solution

Cnidarians which are polyps: Hydra Adamsia

Q115. Differentiate between hibernation and aestivation.

Solution

Hibernation Aestivation 1. It is the period of inactivity in cold weather. 1. It is the inactivity of an animal in hot dry season. 2. It is also called winter sleep. 2. It is also called summer sleep.

Q116. Justify the statement. Ascaris is described as a pseudocoelomate.

Solution

In pseudocoelomates, the body cavity is not lined by the mesoderm. Instead, the mesoderm is present in the form of pouches scattered between the ectoderm and the endoderm. The same arrangement of the three germinal layers is found in Ascaris. Hence, it is described as pseudocoelomate.

Q117. State important features of phylum Annelida. Give any three examples of this phylum.

Solution

Important features of phylum Annelida: Annelids show bilateral symmetry. They show organ system level of organisation. Annelids are triploblastic animals. They exhibit metameric segmentation. Their nervous system consists of paired ganglia and a double ventral nerve cord. They show the presence of a closed circulatory system. Examples of phylum Annelida: Leech, earthworm, Nereis

Q118. State the criteria which form the basis of classification of the animal kingdom.  

Solution

Criteria which form the basis of classification of animal kingdom are     Level of organisation of cells: Some animals show cell-level organisation, some tissue-level and some exhibit organ-level organisation of cells.   Body symmetry: Asymmetrical, bilaterally symmetrical and radially symmetrical.   Nature of coelom: Coelomates, acoelomates and pseudocoelomates.   Presence or absence of notochord: Chordates and non-chordates.   Number of embryonic layers found in animals: Diploblastic and triploblastic conditions.   Segmentation of the body.

Q119. State the difference between urochordates and cephalochordates with reference to the notochord.  

Solution

Urochrodates     Cephalochordates     1) The notochord is present in the larval tail.     1) The notochord extends from the head to the tail region and is persistent throughout their life.        

Q120. Define coelom. Explain the two types of coelom formation in animals.  

Solution

The coelom is the body cavity lined by the mesoderm.     Animals in which the developing embryo shows the presence of a mesoderm between the ectoderm and the endoderm are called triploblastic animals.     In animals such as Aschelminthes, the body cavity is not lined by the mesoderm. The mesoderm is found as scattered pouches present between the ectoderm and the endoderm. Such animals are called pseudocoelomates.           Animals where the body cavity is lined by the mesoderm are called coelomates. Annelids, molluscs, arthropods, hemichordates and chordates are coelomates.              

Q121. What symmetry pattern do humans possess? Which part of the human body is said to be the dorsal part?

Solution

Because the left side of the body is equal and identical to the right side of the body, humans possess bilateral symmetry. Being chordates, humans show the presence of a dorsal notochord during embryonic development which is later replaced by the vertebral column. Hence, the back side or rear of the human body is the dorsal part.

Q122. Differentiate between Annelida and Arthropoda.

Solution

Annelida Arthropoda 1) Body is externally divided into ring-like metameres. 1) Body is divided into head, thorax and abdomen. 2) Annelids show the presence of a closed circulatory system. 2) Arthropods show the presence of an open circulatory system. 3) Locomotion is by chaetae or parapodia. 3) Locomotion is by jointed appendages and/or wings. 4) Excretion occurs by nephridia. 4) Excretion occurs by Malpighian tubules.  

Q123. Why are the animals which belong to phylum Platyhelminthes called flatworms?  

Solution

The animals of phylum Platyhelminthes have their bodies dorsoventrally flattened. Because they appear flat, they are called flatworms.  

Q124. Why is it said that echinoderms show secondary radial symmetry?

Solution

Echinoderms show bilateral symmetry during their larval stage and exhibit radial symmetry in adulthood. Hence, it is said that echinoderms show secondary radial symmetry.

Q125. Write characteristic features of phylum Echinodermata.

Solution

Characteristic features of phylum Echinodermata: 1) Echinoderms show an organ system level of organisation. 2) Their larvae are bilaterally symmetrical and adults exhibit radial symmetry. 3) Echinoderms are triploblastic animals. 4) They are coelomates. 5) They show the presence of a water vascular system which helps in the exchange of gases, excretion and capturing food. 6) The digestive system is complete with mouth on the ventral surface and anus on the upper surface.