Animalia Questions in English

(N/A)

Porifera	Coelenterata
They are mostly marine, non-motile, and found attached to rocks.	They are aquatic, mostly marine, and can be sessile or free-swimming.
They exhibit a cellular level of organization.	They exhibit a tissue level of organization.
The body has pores (ostia) and a central cavity called spongocoel.	The body has a central gastrovascular cavity with a single opening called the hypostome.
Examples: $Spongilla$, $Euplectella$, $Sycon$.	Examples: $Hydra$, $Sea \text{ } anemone$, $Corals$.

(B) The primary differences between annelids and arthropods are as follows:

$1$. Annelids possess a closed circulatory system, whereas arthropods possess an open circulatory system.

$2$. The body of annelids is divided into many identical segments (metamerism), while the body of arthropods is divided into a few specialized segments (tagmatization).

(C)

Amphibian	Reptiles
They have a dual mode of life (aquatic and terrestrial).	They are completely terrestrial.
Skin is moist and scales are absent.	Skin is dry and covered with scales.
They lay eggs in water.	They lay eggs on land.
Examples include frogs,toads,and salamanders.	Examples include lizards,snakes,turtles,and chameleons.

(N/A)

$Aves$	$Mammalia$
$Aves$ possess feathers and a beak.	$Mammals$ do not have feathers and lack a beak.
They are oviparous (egg-laying).	They are mostly viviparous (give birth to young),though some are oviparous.
They have pneumatic (hollow) bones to aid in flight.	They possess mammary glands to nourish their young.

(A) Animals in Vertebrata are classified into five main classes:
$(i)$ Class Pisces: This class includes fish such as $Scoliodon$,tuna,rohu,shark,etc. These animals are aquatic. They possess adaptive features like a streamlined body,a tail for movement,and gills for respiration.
$(ii)$ Class Amphibia: This includes frogs,toads,and salamanders. They have a dual mode of life. In the larval stage,they respire through gills,while in the adult stage,respiration occurs through lungs or skin. They lay eggs in water.
$(iii)$ Class Reptilia: This includes reptiles like lizards,snakes,and turtles. They typically creep or crawl on land. Their body is covered with dry,cornified skin to prevent water loss,and they lay eggs on land.
$(iv)$ Class Aves: This includes all birds such as sparrows,pigeons,and crows. Most possess feathers. Their forelimbs are modified into wings for flight,while hind limbs are adapted for walking and clasping. They lay eggs.
$(v)$ Class Mammalia: This includes animals that possess milk-producing (mammary) glands to nourish their young. Some lay eggs,while others give birth to live young. Their skin features hair,sweat glands,and oil glands to regulate body temperature.

(D) true fish belongs to the class $Pisces$ (or $Chondrichthyes$/$Osteichthyes$).
$Dogfish$ $(Scoliodon)$ is a cartilaginous fish belonging to the class $Chondrichthyes$.
$Jellyfish$ is a member of the phylum $Cnidaria$ (or $Coelenterata$).
$Starfish$ is an echinoderm belonging to the phylum $Echinodermata$.
$Silverfish$ is an insect belonging to the phylum $Arthropoda$.
Therefore,$Dogfish$ is the only true fish among the given options.

(A) The phylum $Echinodermata$ consists of organisms that are exclusively marine.
$Porifera$ (sponges) are mostly marine but some species are found in freshwater.
$Mollusca$ includes both marine and freshwater species.
$Pisces$ (fishes) are found in both marine and freshwater environments.

(B) An open circulatory system is a type of circulatory system where blood is pumped into body cavities,where tissues are surrounded by the blood.
$(i)$ Arthropoda: Most arthropods (e.g.,insects,crustaceans) possess an open circulatory system.
$(ii)$ Mollusca: Most molluscs (except cephalopods like octopus) possess an open circulatory system.
$(iii)$ Annelida: Annelids possess a closed circulatory system.
$(iv)$ Coelenterata: These organisms lack a specialized circulatory system as they rely on diffusion for transport.
Therefore,$(i)$ and $(ii)$ have an open circulatory system.

(C) In $Arthropoda$, the body cavity is a $haemocoel$, which is a blood-filled cavity. The blood flows freely within this cavity, bathing the internal organs directly. This is characteristic of an open circulatory system.

(A) The presence of a notochord is the defining and most striking characteristic of all vertebrates at some stage in their life cycle. While triploblastic condition,gill pouches,and coelom are also found in many non-vertebrate organisms,the notochord is unique to the phylum Chordata,to which all vertebrates belong.

(B) The presence of scales is a characteristic feature of certain vertebrate classes.
$(i)$ Amphibians: Their skin is moist and lacks scales.
$(ii)$ Pisces (Fishes): Most fishes have an exoskeleton of scales.
$(iii)$ Reptiles: Their skin is dry and covered with scales.
$(iv)$ Mammals: Their skin is covered with hair,not scales.
Therefore,both Pisces and Reptiles possess scales. The correct option is $(ii)$ and $(iii)$.

(C) The statement '$C$' is false because not all fishes,amphibians,and reptiles are oviparous.
Some fishes (e.g.,sharks) and some reptiles (e.g.,certain snakes) are viviparous.
Amphibians generally exhibit external fertilization,and while many are oviparous,the classification is not universally applicable to all members of these groups as strictly oviparous.

(A) $Spongilla$ is a freshwater sponge that belongs to the phylum $Porifera$.
$Euglena$ is a unicellular protist belonging to the kingdom $Protista$.
$Penicillium$ is a type of fungus belonging to the kingdom $Fungi$.
$Hydra$ is a freshwater organism belonging to the phylum $Coelenterata$ (also known as $Cnidaria$).

(B) Filaria is a disease caused by the parasitic worm $Wuchereria$ $bancrofti$. It is not an animal itself,but rather a medical condition. In contrast,$Hydra$,$Corals$,and $Jelly$ $fish$ are all aquatic animals belonging to the phylum $Cnidaria$.

(C) Amphibians possess a three-chambered heart consisting of two atria and one ventricle.
They respire through lungs in their adult stage and through gills during their larval (tadpole) stage.
Their skin is moist and contains mucus glands to prevent desiccation.
Unlike reptiles,amphibians lack scales on their skin,which is why they are often referred to as having 'naked' skin.

(B) Protochordates are marine animals that possess a notochord at some stage of their life cycle. They exhibit bilateral symmetry,are triploblastic,and have a coelom. However,jointed legs are a characteristic feature of the phylum $Arthropoda$,which belongs to the kingdom $Animalia$ but is distinct from the phylum $Chordata$ (which includes Protochordata). Therefore,jointed legs are not a feature of Protochordata.

(C) The phylum $Echinodermata$ is characterized by the presence of a water vascular system. The locomotory organs in these organisms are known as $tube feet$ (or $podia$). These structures are used for locomotion, capturing food, and respiration.

(D) Corals belong to the phylum $Cnidaria$ (also known as $Coelenterata$). They are marine invertebrates that typically live in large colonies. These colonies secrete calcium carbonate to form hard,protective skeletons,which eventually build up to form coral reefs.

(B) two-chambered heart consists of one atrium and one ventricle. This type of heart is characteristic of fish,where deoxygenated blood is pumped to the gills for oxygenation and then distributed to the rest of the body. In contrast,amphibians have a three-chambered heart,while crocodiles and aves (birds) possess a four-chambered heart.

(C) Sharks belong to the class $Chondrichthyes$,which are cartilaginous fish,meaning their endoskeleton is composed entirely of cartilage. In contrast,$Rohu$ and $Tuna$ belong to the class $Osteichthyes$,which are bony fish.

(D) Annelids are characterized by metameric segmentation. $Nereis$,Earthworm,and Leech are members of the phylum Annelida. Sea urchins belong to the phylum Echinodermata,not Annelida.

(D) The members of the phylum $Echinodermata$ (such as starfish and sea urchins) possess an endoskeleton made of calcareous ossicles,which are hard structures composed of calcium carbonate. These structures provide support and protection to the organism.

(A) The phenomenon of metameric segmentation,where the body is divided into repeating segments,is a characteristic feature of the phylum $Annelida$.
Leech $(Hirudinaria)$ belongs to the phylum $Annelida$,and therefore,it exhibits differentiation in a segmental fashion.
Starfish belongs to $Echinodermata$,Snails belong to $Mollusca$,and $Ascaris$ belongs to $Aschelminthes$ (or $Nematoda$),none of which exhibit true metameric segmentation.

(C) The presence of jointed legs is a defining characteristic of the phylum $Arthropoda$.
Since insects belong to the class $Insecta$ under the phylum $Arthropoda$,the presence of jointed legs confirms that the animal is an insect.

(N/A) $Spongilla$ - Acoelomate
$Sea \text{ } anemone$ - Acoelomate
$Planaria$ - Acoelomate
$Liver \text{ } fluke$ - Acoelomate
$Wuchereria$ - Pseudocoelomate
$Ascaris$ - Pseudocoelomate
$Nereis$ - Coelomate
$Earthworm$ - Coelomate
$Scorpion$ - Coelomate
$Birds$, $Fishes$, and $Horse$ - Coelomate

(N/A) The classification of the given fishes based on their endoskeleton is as follows:
$1$. $Torpedo$ (Electric ray): Cartilaginous fish (Chondrichthyes).
$2$. $Sting$ $ray$: Cartilaginous fish (Chondrichthyes).
$3$. $Dog$ $fish$ $(Scoliodon)$: Cartilaginous fish (Chondrichthyes).
$4$. $Rohu$ ($Labeo$ $rohita$): Bony fish (Osteichthyes).
$5$. $Angler$ $fish$: Bony fish (Osteichthyes).
$6$. $Exocoetus$ (Flying fish): Bony fish (Osteichthyes).

(N/A) The classification based on the number of heart chambers is as follows:
$1$. $2$-chambered heart: Rohu,Scoliodon.
$2$. $3$-chambered heart: Frog,Salamander,Flying lizard,King Cobra.
$3$. $4$-chambered heart: Crocodile,Ostrich,Pigeon,Bat,Whale.

(N/A) Animals are classified based on their ability to regulate body temperature:
$1$. Cold-blooded (Poikilothermic) animals: These animals cannot maintain a constant body temperature and their body temperature changes with the environment. These include: Rohu (Fish),Scoliodon (Dogfish),Frog (Amphibian),Salamander (Amphibian),Flying lizard (Reptile),King Cobra (Reptile),and Crocodile (Reptile).
$2$. Warm-blooded (Homeothermic) animals: These animals maintain a constant body temperature regardless of the environment. These include: Ostrich (Bird),Pigeon (Bird),Bat (Mammal),and Whale (Mammal).

(N/A) The two egg-laying mammals,also known as monotremes,are:
$(i)$ Platypus (Ornithorhynchus anatinus)
$(ii)$ Echidna (Tachyglossidae family,also known as spiny anteaters)

(N/A) Dorsal fin
$(b)$ Caudal fin
$(c)$ Pelvic fin
$(d)$ Pectoral fin
Function of Caudal fin: The Caudal fin (tail fin) acts as a rudder and helps the fish in steering,balancing,and providing propulsion for streamlined movement in water.

(N/A) No,all these organisms do not belong to the same group.
$1$. Leech and Nereis belong to the phylum $Annelida$ because they exhibit metameric segmentation,meaning their body is divided into many segments internally by septa.
$2$. Scolopendra,prawn,and scorpion belong to the phylum $Arthropoda$ because they possess jointed appendages,a chitinous exoskeleton,and an open circulatory system.

(N/A) Bat,rat,and cat belong to the class $Mammalia$ and share the following common features:
$(a)$ All possess a notochord at some stage of their life cycle.
$(b)$ All are warm-blooded (homeothermic) animals.
$(c)$ All have a four-chambered heart.
$(d)$ All have skin covered with hair and possess sweat and oil glands.

(C) Snakes and turtles are both classified under the class $Reptilia$ because they share several key characteristics:
$(1)$ They are cold-blooded (poikilothermic) animals.
$(2)$ Their skin is dry and covered with scales or scutes.
$(3)$ They breathe exclusively through lungs.
$(4)$ They typically possess a three-chambered heart (except for crocodiles).
$(5)$ They are oviparous,meaning they lay eggs with a tough,leathery,or calcareous covering on land.

(A) The body cavity in certain invertebrates,such as arthropods and molluscs,which is filled with haemolymph (blood) is known as haemocoel.
In these organisms,the circulatory system is open,meaning blood does not remain confined within blood vessels but flows into these open spaces to bathe the tissues directly.

(B) The haemocoel is a body cavity filled with blood,which is a characteristic feature of the phyla Arthropoda and Mollusca. In these animals,the circulatory system is open,meaning blood flows through the body cavity (haemocoel) rather than being confined entirely within blood vessels.

(A) The heart of fishes consists of $2$ chambers,which include one atrium and one ventricle.
In contrast,the heart of frogs consists of $3$ chambers,which include two atria and one ventricle.

(N/A) Liver fluke (Fasciola hepatica) and Planaria belong to the phylum Platyhelminthes. These organisms are commonly known as flatworms because their bodies are dorsoventrally flattened.

(B) Leech (Hirudinaria) and Earthworm (Pheretima) belong to the phylum $Annelida$.
These organisms are characterized by a segmented body,which is a key feature of the phylum $Annelida$.

(N/A) Echinoderms possess a unique water-driven system known as the $Water$ $Vascular$ $System$,which is primarily used for locomotion,capturing food,and respiration.
Their endoskeleton is composed of hard,calcareous structures made of $Calcium$ $Carbonate$ $(CaCO_3)$ plates or ossicles.

(N/A) The term $diploblastic$ refers to organisms whose body cells are arranged in two embryonic layers: an external $ectoderm$ and an internal $endoderm$.
Between these two layers,an undifferentiated layer called $mesoglea$ is present.
Example: $Hydra$ (belonging to the phylum $Cnidaria$).

(N/A) Diploblastic animals are those whose body is made up of two germinal layers (ectoderm and endoderm),whereas triploblastic animals have three germinal layers (ectoderm,mesoderm,and endoderm).
$(b)$ Warm-blooded animals (homeotherms) can maintain a constant internal body temperature regardless of the external environment,whereas cold-blooded animals (poikilotherms) change their body temperature according to the fluctuations in the environmental temperature.

(N/A) notochord is a long,rod-like support structure (the term 'chord' means string) that runs along the back of an animal's body.
It serves to separate the nervous tissue from the gut.
Its primary function is to provide a site for muscle attachment,which facilitates ease of movement for the organism.

(N/A) $X$ represents the tentacles,which are used for capturing prey and locomotion.
$Y$ represents the basal disc (or foot),which is used for attachment to a substrate.

(N/A) $A -$ Mouth
$B -$ Dorsal fin
$C -$ Pectoral fin
$D -$ Brood pouch (This is where the male carries the eggs until they hatch.)

(N/A) Characteristic features of nematodes:
$(i)$ Nematodes have a cylindrical,bilaterally symmetrical,and triploblastic body.
$(ii)$ They are often parasitic and can cause diseases in plants and animals.
$(b)$ $(i)$ The phylum is $Echinodermata$. These organisms possess a spiny skin (calcareous ossicles),radial symmetry in adults,and a water vascular system with tube feet for locomotion.
$(ii)$ The phylum is $Annelida$. These organisms are triploblastic,coelomate,and exhibit true segmentation (metamerism) in their worm-like bodies.

(D) Bats are not classified as birds because:
$(i)$ They lack feathers,which are a characteristic feature of birds.
$(ii)$ They possess mammary glands,which is a defining characteristic of mammals.
$(iii)$ They give birth to live young ones rather than laying eggs.
$(iv)$ Their body is covered with hair instead of feathers.

(A) Arthropoda: These organisms possess jointed appendages,which is a characteristic feature of this phylum.
$(b)$ Platyhelminthes: These organisms are commonly known as flatworms due to their dorso-ventrally flattened bodies.
$(c)$ Annelida: These organisms exhibit true segmentation or metamerism in their body structure.
$(d)$ Echinodermata: These organisms have a spiny-skinned body surface,which is a diagnostic feature of this phylum.

(N/A) Lizards: They possess two pairs of pentadactyl limbs.
Snakes: Pentadactyl limbs are absent.
$(b)$ Fungi exhibit a saprophytic mode of nutrition,where they absorb nutrients from dead and decaying organic matter.

(N/A) The phylum to which Ascaris belongs is Nematoda (or Aschelminthes).
Two characteristic features of this phylum are:
$1$. The body is cylindrical in shape and circular in cross-section.
$2$. They are pseudocoelomate,meaning they possess a false body cavity.
The parasitic worm that causes elephantiasis (filariasis) is Wuchereria bancrofti (commonly known as the Filarial worm).

(N/A) Platyhelminthes are acoelomate,meaning they lack a true body cavity (coelom).
They exhibit both lifestyles: many species are parasitic (e.g.,Tapeworms,Liver flukes),while some are free-living (e.g.,Planaria).