Additional Questions - Chapter 2 Kingdom Animalia 11th Biology Zoology Guide Samacheer Kalvi Solutions - SaraNextGen [2024-2025]

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On April 24, 2024, 11:35 AM

Additional Questions & Answers
Multiple Choice Question And Answer
Choose the correct answer
Question 1.
Which of the following has loose aggregates of cells without tissues?
(a) cnidarians
(b) flatworms
(c) sponges
(d) echinodenns
Answer:
(c) sponges
Question 2.
Which of the following has open type of circulation?
(a) frogs
(b) garden lizard
(c) man
(d) cockroach
Answer:
(d) cockroach
Question 3.
Which of the following is advantageous for the animals in locomotion, food capture etc.?
(a) asymmetrical
(b) radially symmetrical
(c) biradially symmetrical
(d) bilaterally symmetrical

Answer:
(d) bilaterally symmetrical
Question 4.
Which of the following restricts the free movement of internal organs?
(a) acoelom
(b) pseudocoelom
(c) schizocoelom
(d) enterocoelom
Answer:
(a) acoelom
Question 5.
Radiata include
(a) Diploblastic and bilaterally symmetrical animals
(b) Triploblastic and radially symmetrical animals
(c) Diploblastic and radially symmetrical animals
(d) Triploblastic and bilaterally symmetrical animals
Answer:
(c) Diploblastic and radially symmetrical animals.
Question 6.
The minute pores on the body of sponges are called
(a) oseuliem
(b) ostia
(c) choanocytes
(d) spongocoel
Answer:
(b) ostia
Question 7.
Which of the following statements is correct?
(a) Polyp forms are free-living
(b) Medusa forms are sessile
(c) Medusa produces gametes
(d) Polyp reproduces sexually

Answer:
(c) Medusa produces gametes
Question 8.
Which of the following is the adaptation of flatworms for the endoparasitic mode of life?
(a) They are dorsoventrally flattened
(b) They have hooks, suckers or both
(c) Their body is not segmented
(d) They reproduce sexually
Answer:
(b) They have hooks, suckers or both
Question 9.
Sexual dimorphism is seen in -
(a) Sycon
(b) Hydra
(c) Liver flukes
(d) Ascaris
Answer:
(d) Ascaris
Question 10.
Which of the following shows metamerically segmented body?
(a) Aschelminthes
(b) Annelida
(c) Arthropoda
(d) Platyhelminthes
Answer:
(b) Annelida
Question 11.
Which of the following is the characteristic feature of the phylum Arthropoda?
(a) They have segmented legs
(b) They have collablasts for food capture
(c) They are end oparasites of animals

(d) They do not have chitinous exoskeleton
Answer:
(a) They have segmented legs
Question 12.
Which of the following is the rasping organ of molluscs found in the mouth?
(a) radula
(b) pallium
(c) misceral mass
(d) mantle
Answer;
(a) radula
Question 13.
Which of the following is bilaterally symmetrical in larval stages and radially symmetrical in adult?
(a) Molluscs
(b) Echinoderms
(c) Arthropods
(d) Annelids
Answer:
(b) Echinoderms
Question 14.
Which of the following has the anterior proboscis, collar and trunk?
(a) Ascidian
(b) Star fish
(c) Sea cucumber
(d) Balanoglossus
Answer:
(d) Balanoglossus
Question 15.
Urochordate means
(a) Chordates which have notochord in the head region
(b) Chordates which have notochord in the tail region of larval forms

(c) Chordates which have notochord in the tail region of adults
(d) Chordates which have no notochord
Answer:
(b) Chordates which have notochord in the tail region of larval forms.
Question 16.
Which of the following loses all the chordate characters in the adult stage?
(a) Cephalochordates
(b) Hemichordates
(c) Tunicates
(d) Chordates
Answer:
(c) Tunicates
Question 17.
Which of the following has cartilagenous endoskeleton with notochord?
(a) Exocoetus
(b) Labeo
(c) Hyla
(d) Scolidon
Answer:
(d) Scolidon
Question 18.
Which is the class of animals adapted for dual mode of life?
(a) Pisces
(b) Amphibia
(c) Reptilia
(d) Mammalia
Answer:
(b) Amphibia
Question 19.
Which of the following is the flight adaptation of birds?
(a) Pneumatic bones and strong flight muscles
(b) Homeothermic condition

(c) Migration to distant places
(d) Presence of homy covering on the beak
Answer:
(a) Pneumatic bones and strong flight muscles
Question 20.
Which of the following are truly terrestrial animals?
(a) Lung fishes
(b) Amphibians
(c) Mammals
(d) Reptiles
Answer:
(d) Reptiles
II Give Reasons
Question 1.
Closed type of circulation is advanced.
Answer:
Closed type of circulation is found in higher organisms like prochordates and vertebrates. The invertebrates have open type of circulation except annelids. The closed type of circulation is advanced because blood flows in blood vessels. There is a clear separation of oxygenated and deoxygenated blood.
Question 2.
Pseudocoelomates are more advanced than acoelomates.
Answer:
Acoelomates do not have body cavity. Their body is solid and hence the movement of internal organs is restricted. Pseudocoelomates have pseudocoelomic fluid in the pseudocoelom. It acts as a hydrostatic skeleton and allows free movement of visceral organs and circulation of nutrients.
Question 3.
Sponges are primitive animals.
Answer:
Sponges have cellular grade of organisation. Tissues are not formed. The cells are loosely arranged. The division of labour is found among the group of cells.

Question 4.
Bioluminence is advantageous to ctenophores.
Answer:
Ctenophores are exclusively marine. They emit light. It helps the animals in finding food, mate and escape from the predators.
Question 5.
Tape worm and liver fluke are not destroyed by the digestive juices secreted by human beings.
Answer:
The body of helminth parasites is covered by a thick covering called tegument. This protects the worms. They have hooks, suckers or both for attachment.
Question 6.
All vertebrates are chordates but all chordates are not vertebrates.
Answer:
All Vertebrates have notochord during embryonic development. Later it is replaced by the vertebral column. But in lower chordates like prochordates, vertebral column is not present. They have only notochord in the adult or larval stage. Hence it is said that all vertebrates are chordates but all chordates do not have vertebrate characters
Answer the following
Questions 1.
Distinguish invertebrates and chordates.
Answer:
Invertebrates:
- The major group of animals which do not have notochord or vertebral column are Invertebrates.
- These are lower animals.
Chordates:
- The major group of animals which have notochord or vertebral column are chordates.

- These are higher animals.
Question 2.
Distinguish between invertebrates and vertebrates.
Answer:
Invertebrates:
- The major group of animals which do not have notochord or vertebral column are Invertebrates.
- These are lower animals.
Vertebrates:
- The major group of animals which have vertebral column are vertebrates
- These are higher animals.
Question 3.
What are choanocytes?
Answer:
The inner layer of sponges have a special type of cells called choanocytes. These flagellated collar cells create and maintain water flow through the sponge. It helps in respiration and digestion.
Question 4.
Distinguish between open type of circulation and closed type of circulation.
Answer:
Open Type of circulation:
- The circulation in which blood remains filled in tissue spaces is known as open type of circulation.
- This is seen in lower organisms, e.g. arthropods, molluscs echinoderms and urochordates.
Closed type of circulation:
- The circulation in which blood flows inside the blood vessels is known as closed type of circulation.

- This is seen in higher organisms, e.g. Annelids, cephalochordates and vertebrates.
Question 5.
Distinguish between Diploblastic animals and triploblastic animals.
Answer:
Diploblastic animals:
- The animals in which the cells are arranged in two embryonic layers, the ectoderm and endoderm are called diploblastic animals.
- These are lower organisms, e.g. Cnidaria and ctenophora
Triploblastic animals:
- The animals in which the cells are arranged in three embryonic layers, the ectoderm, mesoderm and endoderm are called triploblastic animals.
- These are higher organisms, e.g. Platyhelminthes to mammalia.
Question 6.
What are asymmetrical animals?
Answer:
The animals which lack a definite body plan and any plane passing through the center of the body does not divide them into two equal halves are known as asymmetrical animals, e.g. Sponges.
Question 7.
What is radial symmetry?
Answer:
When any plane passing through the central axis of the body divides an organism into two identical parts, it is called radial symmetry, e.g. Cnidarian.
Question 8.
What is bilateral symmetry?
Answer:
The symmetry in which the animals have two similar halves on either side of the central place is bilateral symmetry, e.g. Flatworms and annelids.

Question 6.
What are asymmetrical animals?
Answer:
The animals which lack a definite body plan and any plane passing through the center of the body does not divide them into two equal halves are known as asymmetrical animals, e.g. Sponges.
Question 7.
What is radial symmetry?
Answer:
When any plane passing through the central axis of the body divides an organism into two identical parts, it is called radial symmetry, e.g. Cnidarian.
Question 8.
What is bilateral symmetry?
Answer:
The symmetry in which the animals have two similar halves on either side of the central place is bilateral symmetry, e.g. Flatworms and annelids.

Question 14.
Distinguish between schizocoelomates and enterocoelomates
Answer:
Schizocoelomates:
In schizocoelometes, the body cavity is formed by splitting of mesoderm, e.g. Annelids, arthropods and molluscs.
Enterocoelomates:
In enterocoelomates, the body cavity is formed from the mesodermal pouches of archenteron. e.g. Echinoderms, hemichordates and chordates.
Question 15.
Distinguish between parazoa and eunietazoa.
Answer:
Parazoa:
These include multicellular animals whose cells are loosely arranged without the formation of tissues or organs, e.g. Sponges
Eumetazoa:
These include multicellular animals with well defined tissues, organs and organ systems.
Question 16.
Distinguish between radiata and bilateria.
Answer:
Radiata:
- These include radially symmetrical animals.
- There are diploblastic e.g., Cnidarians and ctenophores
Bilateria:
- These include bilaterally symmetrical animals.
- There are triploblastic. e.g. Flat - worms
Question 17.
Distinguish between protostomia and deuterostomia.

Answer:
Protostomia:
- These include the eumetazoans in which embryonic blastopores develops into mouth.
- Acoelomata, pseudocoelomata and schizocoelomata are the three sub divisions of this division.
Deuterostomia:
- These include the cutnetazoans in which embryonic blastopore develops into anus.
- Enterocoelmata is the only one subdivision of this division.
Question 18.
What is canal system?
Answer:
The water transport system in sponges through which water enters through minute opores and goes out through the large opening called osculum. It helps in nutrition, circulation, respiration and excretion.
Question 19.
Distinguish between ostia and osculum.
Answer:
Ostia:
- The minute pores lining the body wall of sponges are called ostia.
- Water enters through ostia.
Osculum:
- The large opening in sponges is called osculum.
- Water goes out through osculum.
Question 20.
What spongocoel?
Answer:
The central cavity of the sponges is called spongocoel.

Question 21.
What are choanocytes?
Answer:
Choanocytes are the collar cells lining the spongocoel and the canals of sponges. These are helpful in creating water current in sponges.
Question 22.
Distinguish between asexual reproduction and sexual reproduction.
Answer:
Asexual Reproduction:
- The reproduction without involvement of gametes is called Asexual Reproduction.
- Zygote is not formed.
Sexual Reproduction:
- The reproduction with the involvement of gametes is called sexual reproduction.
- Zygote is formed by the process called fertilization.
Question 23.
Name the larvae of sponges.
Answer:
Parenchymula and amphiblastula.
Question 24.
What is indirect development?
Answer:
The development with different types of larval stages is called indirect development.
Question 25.
What is holozoic nutrition?
Answer:
The nutrition in which solid food materials are taken in by animals is called holozoic nutrition.

Question 26.
What are cnidocytes or cnidoblasts or nematocysts?
Answer:
The stinging cells found on the tentacles of cnidarians are called cnidocytes or cnidoblasts or nematocysts. They are useful for anchorage, defense and capturing prey.
Question 27.
What is coelenteron?
Answer:
The central visceral cavity of cnidarians is called coelenteron.
Question 28.
Distinguish between polyp and medusa.
Answer:
Polyp:
- The sessile body form of cnidarians is called polyp.
- It is the asexual generation
Medusa:
- The free living body form of cnidarians is called medusa.
- It is the asexual generation
Question 29.
What is metagenesis or Alternation of generation?
Answer:
The cnidarians exhibit sexual and asexual forms that alternate with each other. This is called metagenesis or Alternation of generation.
Question n 30.
Name the larva of cnidarians?
Answer:
Planula larva.

Question 31.
What are lasso cells or colloblasts?
Answer:
The special cells of ctenophores which helps in food capture are lasso cells or colloblasts.
Question 32.
Name the larva of ctenophores?
Answer:
Cydippid larva.
Question 33.
What are solanocytes?
Answer:
The specialized excretory cells of flatworms, flame cells are called solanocytes.
Question 34.
What are the larvae of flatworms?
Answer:
Miracidium, Sporocyst, redia, cercaria and metacercaria.
Question 35.
What is regeneration?
Answer:
The ability to regrow the lost parts is called regeneration, e.g. Planaria.
Question 36.
What is metamerism? -
Answer:
The body of annelids are divided into segments. This phenomenon is known as metamerism.
Question 37.
Name the respiratory pigments of annelids?
Answer:
Haemoglobin and chlorocruorin.

Question 38.
Name the larva of annelids.
Answer:
Trochophore larva.
Question 39.
What is moulting or ecdysis?
Answer:
The chitinous exoskeleton of arthropods is shed periodically. This process is known as moulting or ecdysis.
Question 40.
What are the respiratory organs of arthropods?
Answer:
Gills, Book gills, Book lungs and trachea.
Question 41.
Name the sensory organs of arthropods?
Answer:
Antennae, Simple and compound eyes and statocysts.
Question 42.
What are ctenidia?
Answer:
The feather like gills of molluscs are called ctenidia.
Question 43.
What is radula?
Answer:
The rasping organ found in the mouth of molluscs is called radula.
Question 44.
What is the function of ospharidium?
Answer:
Ospharidium are helpful to test the purity of water.

Question 45 .
Name the respiratory pigment of molluscs.
Answer:
Haemocyanin, a copper containing pigment.
Question 46.
Name the larva of molluscs?
Answer:
Veliger larva.
Question 47.
What is water vascular system?
Answer:
The system which helps in nutrition and respiration in echinoderms is called water vascular system. Water enters into the body through special organs.
Question 48.
Name the larva of hemichordates?
Answer:
Tornaria larva.
Question 49.
What are urochordates?
Answer:
The chordates which have notochord only in the tail region of the larval stage are called urochordates e.g. Ascidian.
Question 50.
Distinguish between Agnatha and Gnathostomata.
Answer:
Agnatha:
- These include jawless fish-like aquatic vertebrates.
- They do not have paired appendages.
Gnathostomata:

- These include jawed vertebrates.
- They have paired appendages.
Question 51.
What are poikilothermic?
Answer:
The animals which change their body temperature according to the environment are called poikilothermic.
Question 52.
What is anadromous migration?
Answer:
The migration of marine fishes to fresh water body like rivers for spawning is known as anadromous migration.
Question 53.
Distinguish between oviparous and viviparous animals.
Answer:
Oviparous animals:
- The egg laying animals are known as oviparous animals.
- They lay eggs containing yolk for embryonic development e.g. birds.
Viviparous animals:
- The animals which give birth to young ones are called viviparous animals.
- The developing embryo derives nutrients from the parent, e.g. man
Question 54.
What are Ammonotelic animals?
Answer:
The animals which excrete ammonia dissolved in water are called ammonotelic animals. More water is spent, e.g. fishes.
Question 55.
What are ureotelic animals?

Answer:
The animals which excrete urea along with water are called ureotelic animals. Less water is spent e.g. man.
Question 56.
What are urecotelic animals?
Answer:
The animals which excrete uric acid in the form of pellets are called urecotelic animals. Very less water is spent e.g. birds.
Question 57.
Distinguish between hibernation and aestivation.
Answer:
Hibernation:
- The dormancy period for animals during winter is called hibernation.
- It is known as winter sleep.
Aestivation:
- The dormancy period for animals during summer is called Aestivation.
- It is know as summer sleep.
Question 58.
Distinguish between cleidoic eggs and non-cleidoic eggs.
Answer:
Cleidoic eggs:
- The eggs which have a thick and hard outermost shell are cleidoic eggs.
- This is a terrestrial adaptation, e.g., Reptiles and birds.
Non Cleidoic eggs:
- The eggs Which do not have a protective shell are non - Cleidoic eggs
- This is seen in aquatic animals, e.g., Fishes, amphibians.
Question 59.
What is rhamphotheca?

Answer:
The homy covering on the beak of birds is called rhamphotheca.
Question 60.
Name some flightless birds.
Answer:
Ostrich, kiwi and penguin.
Question 61.
Distinguish between poikilothermic and homeothermic.
Answer:
Poikilothermic:
- The animals which change their body temperature according to the environment are called poikilothermic animals.
- These cold blooded animals, e.g., fishes, amphibians and reptiles.
Homeothermic:
- The animals which maintain constant body temperature irrespective of environmental changes are called homeothermic animals.
- These are warm blooded animals, e.g., birds and mammals.
Question 62.
Explain various patterns of organisation in animals.
Answer:
Animals exhibit different patterns of organisation:
Cellular level of organisation :
- Cells are loosely arranged without the formation of tissues.
- There is division of labour among the cells, e.g., sponges.
Tissue level of organisation :
- Cells which perform similar function are grouped into tissues.
- The tissues perform a common function, e.g., cnidarians.

Organ level of organisation :
Different kinds of tissues aggregate to form an organ to perform a specific function e.g., flatworms and other hyper phyla.
Organ system level of organisation :
- The tissues are organised to form organs and organ systems.
- All the organ system function in a coordinated manner.
Question 63.
Explain symmetry in animals.
Answer:
Symmetry is the body arrangement in which parts lie on opposite side of the axis are identical. If the animals lack a definite body plane or irregular shaped and any plane passing through the center of the body does not divide them into two equal halves, these are known as asymmetrical, e.g., sponges, adult gastropods.
When any plane passing through the central axis of the body divides an organism into two equal parts, it is known as radial symmetry. They have a top and bottom side, e.g., cnidarians. Echinoderms have five planes of symmetry and show pentamerous radial symmetry. Animals which have two pairs of symmetrical sides are biradially symmetrical. Animal which have two similar halves on either side of the control plane show bilateral symmetry.
Question 64.
Classify animals based on coelom.
Answer:
The cavity between the body wall and the gut wall is called coelom. If the animals do not have coelom, they are called acoelomates. e.g., flatworms. In some animals, the body cavity is not fully lined by the mesodermal epithelium. The mesoderm is formed as scattered pouches between the ectoderm and endoderm. Such a body cavity is called a pseudocoel. The animals which have pseudocoel e.g. round worms.
If the coelom develops within the mesoderm and is lined by mesodermal epithelium it is called eucoelom. The animals which have true coelom are called eucoelomates. If the body cavity is formed by splitting of mesoderm, the animals are called schizocoelomates e.g., Annelids, arthropods and molluscs. If the body cavity is formed from the mesodermal ' pouches of archenteron, the animals are called enterocoelomate animals, e.g., echinoderms, hemichordates and chordates.
Question 65.
Classify the animal kingdom.
Answer:

Question 66.
Write the general characters of the phylum porifera.
Answer:
- They are aquatic, asymmetrical.
- They have pores all over the body.
- They are multicellular with cellular level of organisation. Tissues are not formed.
- They have canal system for circulation of water.
- They have skeleton made of calcareous or siliceous spicules.
- Nutrition is holozoic and digestion intracellular.
- Asexual reproduction by fragmentation and gemmule formation.
- Indirect development with parenchymula and amphiblastula larvae, e.g., Sycon and Spongilla.
Question 67.
Write the general characters of the phylum cnidaria.
Answer:
- The cnidaria are aquatic, radially symmetrical and diploblastic.
- The tentacles have stinging cells called cnidocytes or cnidoblasts or nematocysts.
- They exhibit tissue level of organisation.
- They have a central gastrovascular cavity called coelenderon.
- Digestion is by both extracellular and intracellular.
- Alternation of generation is seen in cnidarians which have polyp and medusa forms.

- Development is indirect with planula larva e.g. Physalia.
Question 68.
Write the general characters of the phylum ctenophora.
Answer:
- The animals are marine, diploblastic and radially symmetrical.
- They have eight external rows of ciliated comb plates which help in locomotion.
- Bioluminescence is seen.
- They lack nematocysts but have lasso cells which help in food capture.
- Digestion is by both extracellular and intracellular.
- Sexual reproduction is seen.
- Fertilization is external and development is indirect.
- Cydippid larva is seen, e.g., Pleurobrachia.
Question 69.
Write the general characters of flatworms.
Answer:
- The flatworms are flat, bilaterally symmetrical, triploblastic animals.
- These are acoelomates with organ system level of organisation.
- They are endoparasites. They have hooks or suckers or both.
- They show pseudosegmentation.
- Flame cells or solanocytes are the excretory cells.
- Sexes are not separate.
- Fertilization is internal. Development is indirect with many larval stages like miracidium sporocyst, redia, cercaria and metacercaria. e.g., Taenia and liver fluke.
Question 70.
Write the general characters of the phylum aschelminthes.
Answer:
- The body of these worms is circular.
- They are free living or parasite.
- They are triploblastic, pseudocoelomates with organ system level of organisation.
- Body is covered by cuticle.
- Digestive system is complete with mouth, pharynx and anus.
- Excretory system consists of rennet glands.
- Sexes are separate. Sexual dimorphism is seen.
- Fertilization is internal.
- Development may be direct or indirect, e.g., Ascaris.
Question 71.
Write the general characters of the phylum annelida.
Answer:
- They are aquatic or terrestrials, free living or parasitic.
- They are triploblastic, bilaterally symmetrical, schizocoelomates with organ system level of organisation.
- The body is metamerically segmented.
- Longitudinal and circular muscles help in locomotion.
- Closed type of circulation is seen.
- Respiratory pigments are present.
- Sexual reproduction is seen. Development is direct or indirect with a trochophore larva e.g., earthworm.

Question 72.
Write the general characters of the phylum arthropoda.
Answer:
- These are bilaterally symmetrical, triploblastic, schizocoelomate, segmented animals.
- They have organ system grade of organisation.
- They have jointed appendages.
- Body is covered by chitinous exoskeleton. Body is divided into head, thorax and abdomen.
- Body cavity is filled with colourless blood. It is called haemocoel.
- Respiratory organs are gills, book gills, book lungs, trachea.
- Open type circulation is seen.
- Sense organs are present.
- Fertilization is internal, e.g., Limulus and insects.
Question 73.
Write the general characters of the phylum mollusca.
Answer:
- Molluscs are terrestrial or aquatic with organ system level of organisation.
- They are triploblastic, bilaterally symmetrical, coelomate animals.
- Body is divided into head, foot and visceral hump.
- The digestive system is complete.
- Nephridia are the excretory organs.
- Open type of circulatory system is seen.
- Blood contains copper containing respiratory pigment called hemocyanin.
- They are oviparous.
- Development is indirect with a veliger larva, e.g., Pila and Octopus.
Question 74.
Write the general characters of the phylum echinodermata.
Answer:

- The adults are radially symmetrical but the larvae are bilaterally symmetrical.
- They have mesodermal endoskeleton of calcareous ossicles called spines.
- Water vascular system is present.
- Tube feet are the organs of locomotion, respiration and capture of food.
- The digestive system is complete with mouth on the ventral side and anus on the dorsal side.
- Excretory organ are absent.
- Open type of circulatory system is present.
- Reproduction is by sexual method.
- Fertilization is external.
- Indirect development with bilaterally symmetrical larval forms, e.g., starfish.
Question 75.
Write the general characters of hemichordata.
Answer:
- The Hemichordates have both invertebrate and vertebrate characters.
- They are worm like, tubiculous animals.
- They are bilaterally symmetrical, triploblastic coelomate animals with organ system level of organisation.
- The body is divided into proboscis, collar and trunk.
- They are ciliary feeders.
- Circulatory system is simple and open.
- Excretion is by a single proboscis gland or glomerulus situated in the proboscis.
- Sexes are separate.
- Fertilization is external.
- Development is indirect with tomaria larva, e.g., Balanoglossus.
Question 76.
Write the general characters of urochordates or tunicates.
Answer:

- They are marine, sessile, pelagic or free swimming.
- Body is unsegmented and covered by a test or tunic.
- Ault forms are sac like.
- Coelom is absent.
- Notochord is present only in the tail region of the larval stage.
- Heart is ventral and tubular.
- Nerve cord is present only in the larval stage.
- They are hermaphrodites and development is indirect with a free swimming tadpole larva.
- Retrogressive metamorphosis is seen e.g. Ascidia.
Question 77.
Write the general characters of cephalochordates.
Answer:
- They are marine found in shallow waters.
- They lead a burrowing mode of life.
- They are fish like with notochord, nerve cord and pharyngeal gill slits throughout their life.
- Closed type of circulatory system is seen without heart.
- Excretion is by protonephridia.
- Sexes are separate.
- Fertilization is external.
- Development is indirect with a larva e.g. Amphioxus.
Question 78.
Write the general character of the subphylum vertebrata.
Answer:
- The vertebrates have notochord during embryonic stage. In adult, it is replaced by vertebral column.,
- They have paired appendages.
- The skin is covered by protective skeleton like scales, feathers, hairs, claws, nails etc.
- Respiration is by gills, skin, buccopharyngeal cavity and lungs.
- They have a ventral heart with two, or three or four chambers.

Question 80.
Write the general characters of the class Cyclostomata.
Answer:
- They are primitive, poikilothermic, jawless aquatic vertebrates.
- Body is slender and eel-like with six to fifteen pairs of gill slips.
- Mouth is circular without jaws and suctorial.
- Heart is two chambered. Closed types of circulation is seen.
- No paired appendages.
- Cranium and vertebral column are cartilaginous, e.g. Petromyzon.
Question 81.
Write the general characters of the class chondrichthyes.
Answer:
- They are cartilaginous marine fishes. .
- Notochord is persistent throughout life.
- The skin is covered by dermal placoid. scales.
- Caudal fin is heterocercal.
- Jaws are powerful.
- Respiration is by lamelliform gills without operculum.
- Mesonephric kidneys are present.
- They have two chambered heart.
- They are ureotelic.
- They are poikilothermic and viviparous.
- Sexes are separate and fertilization is internal, e.g., Scoliodon.

Question 82.
Write the general characters of the class osteichthyes.
Answer:
- They are marine or freshwater fishes.
- They have bony endoskeleton.
- The body is spindle-shaped.
- The skin is covered by ganoid, cycloid or ctenoid scales.
- Respiration is by four pairs of gills covered by operculum.
- Air bladder is present which helps in gaseous exchange (lung fishes) for maintaining buoyancy.
- They have two chambered heart.
- They have mesonephric kidneys and ammonotelic.
- Lateral line sense organ is present.
- External fertilization is seen and most forms are oviparous e.g. Labeo and Catla.
Question 83.
Write the general characters of the class Amphibia.
Answer:
Amphibians are adapted to live both in water and on land.
- They are poikilothermic.
- The body is divisible into head and trunk.
- They have two pairs of limbs.
- The skin is smooth or rough, moist, pigmented and glandular.
- Eyes have eyelids.
- Respiration is by gills, lungs and through the skin.
- Heart is three chambered.
- Kidneys are mesonephric and ureotelic.
- Sexes are separate and fertilization is external.

- They are oviparous and development is indirect, e.g. Bufo and Rana.
Question 84.
Write the general characters of the class Reptilia.
Answer:
- They are mostly terrestrial.
- The body is covered by dry and comified skin with scales.
- They have three chambered heart.
- They are poikilothermic.
- They are oviparous and they lay cleidoic eggs.
- They have metanephric kidney and are uricotelic.
- Fertilization is internal, e.g. Chelone and Chameleon.
Question 85.
Write the general characters of the class Aves.
Answer:
- They have feathers on the body.
- The forelimbs are modified into wings. The hind limbs are adapted for walking, running, swimming and perching.
- The skin has oil gland.
- The exoskeleton consists of feathers, scales, claws on legs.
- The bones are pneumatic.
- Respiration is by lungs with air sacs.
- The heart is four chambered with right systemic arch.
- They are homeothermic.
- Migration and parental care are seen.
- Urinary bladder is absent.
- Females have only left ovary.
- They are oviparous. The eggs are cleidoic.
Question 86.
Write the general characters of the class Mammalia.
Answer:
- The body is covered by hairs.

- They have mammary glands.
- They have two pairs of limbs adapted for walking, running, climbing, burrowing, swimming and flying.
- The skin has sweat glands, scent glands and sebaceous glands.
- Exoskeleton includes homy epidermal horns, spines, claws, nails, hooves and bony dermal plates.
- They have thecodont, heterodont and diphyodont teeth.
- External ears or pinnae are present.
- Heart is four chambered with left systemic arch.
- RBCs are non-nucleated.
- They have metanephric kidneys and they are ureotelic.
- They are homeothermic.
- Sexes are separate and fertilization is internal e.g. Platypus, kangaroo, elephants and man.