Phylum-Arthropoda Questions in English

(A) Silverfish ($Lepisma$ $saccharina$) is a small,wingless insect.
Insects belong to the phylum $Arthropoda$ because they possess jointed appendages and a chitinous exoskeleton.
Despite its name,it is not a fish $(Pisces)$ but an invertebrate belonging to the class $Insecta$ under the phylum $Arthropoda$.

(A) In the phylum $Arthropoda$,the circulatory system is of the open type. In an open circulatory system,blood is pumped out of the heart into blood spaces or sinuses called $haemocoel$. Because the blood is not confined to vessels,it flows at a low pressure,the volume of blood is relatively high,and the flow is irregular as it bathes the tissues directly.

(D) In prawns (Crustacea),the sensory organs include:
$1$. Chemoreceptors and tangoreceptors: These are present on the antennae and antennules to detect chemical changes and touch.
$2$. Statocysts: These are balancing organs located at the base of the antennules.
$3$. Auditory organs: Prawns possess sensory structures that respond to vibrations in the water.
Therefore,all the listed options are sensory organs found in prawns.

(B) The cephalothorax is a body region found in many arthropods,such as crustaceans and arachnids. It is formed by the fusion of the head $(cephalon)$ and the thorax $(thorax)$. This fused structure provides a rigid protective covering for the vital organs located in the anterior part of the body.

(A) Parthenogenesis is a form of asexual reproduction in which an embryo develops from an unfertilized egg. In the phylum $Arthropoda$,specifically within the class $Insecta$ (e.g.,honey bees,aphids),parthenogenesis is a well-documented phenomenon. Therefore,the correct group is $Arthropoda$.

(C) Crustaceans,which belong to the phylum $Arthropoda$,typically use $Hemocyanin$ as their respiratory pigment.
$Hemocyanin$ is a copper-containing protein that turns blue when oxygenated.
Unlike $Hemoglobin$,which contains iron and is found in red blood cells,$Hemocyanin$ is dissolved directly in the hemolymph of these organisms.

(D) $Hemocyanin$ is a copper-containing respiratory pigment that gives blood a blue color when oxygenated.
It is commonly found in the hemolymph of many mollusks and arthropods,such as crustaceans (e.g.,prawns,crabs,and lobsters).
Earthworms use $Hemoglobin$ (dissolved in plasma).
Cockroaches have an open circulatory system without respiratory pigments in their hemolymph.
Frogs use $Hemoglobin$ (contained in red blood cells).
Therefore,the correct answer is $Prawn$.

(C) In crustaceans (a group of arthropods),the respiratory pigment is $Hemocyanin$.
$Hemocyanin$ is a copper-containing protein that binds to oxygen and gives the blood a blue color when oxygenated.
Unlike hemoglobin,which contains iron and is found in red blood cells,hemocyanin is dissolved directly in the hemolymph of crustaceans.

(A) : Parapodia are flattened,fleshy,lateral outgrowths of the body wall found in $Annelida$. These are not present in $Arthropoda$. $Arthropoda$ are characterized by jointed appendages,a chitinous exoskeleton,and metameric segmentation. Parapodia serve the purpose of locomotion and respiration in annelids like $Nereis$.

(A) : The exoskeleton,composed of a chitinous cuticle,is the primary factor that has enabled insects to colonize land and diversify into almost all possible habitats. It provides essential protection,structural support,and significantly helps in preventing desiccation (water loss).

(D) : Phylum $Arthropoda$ is the largest phylum of $Animalia$ which includes insects.
Examples include $Apis$,silkworm,$Laccifer$,silver fish $(Lepisma)$,locust,etc.
Puffer fish and flying fish $(Exocoetus)$ are examples of superclass $Pisces$,while cuttle fish $(Sepia)$ belongs to phylum $Mollusca$.

(C) is the correct answer. Arthropoda is the largest phylum of Kingdom Animalia,characterized by a chitinous exoskeleton. The body is typically divided into three distinct regions: head,thorax,and abdomen. Respiration in terrestrial arthropods occurs through specialized structures such as tracheae,book lungs,or book gills.

(C) : Centipede,cockroach,and crab all belong to the phylum $Arthropoda$,which is characterized by the presence of jointed legs and a chitinous exoskeleton.
Arthropods possess a bilaterally symmetrical and metamerically segmented body with a haemocoel and an open blood vascular system.

(C) The classification of insects based on their orders is as follows:
$1$. Lepidopterans include tobacco budworm and armyworm.
$2$. Coleopterans include beetles.
$3$. Dipterans include flies and mosquitoes.
$4$. Crabs belong to the phylum Arthropoda but are classified under the class Crustacea,not Insecta. Therefore,the pair 'Insects - Crab' is false.

(C) The classification hierarchy of organisms is organized into categories: Kingdom,Phylum,Class,Order,Family,Genus,and Species.
$Insecta$ is a class within the phylum $Arthropoda$.
$Diptera$ is an order within the class $Insecta$.
$Musca$ is a genus within the family $Muscidae$.
Therefore,the correct phylum for $Insecta$ is $Arthropoda$.

(B) To determine the correct group,we must identify the phylum for each organism:
$1$. Option $A$: Earthworm (Annelida),Liver fluke (Platyhelminthes),Tapeworm (Platyhelminthes). These do not belong to the same phylum.
$2$. Option $B$: Prawn (Arthropoda),Scorpion (Arthropoda),Locusta (Arthropoda). All these organisms belong to the phylum $Arthropoda$.
$3$. Option $C$: Sponge (Porifera),Sea anemone (Cnidaria),Starfish (Echinodermata). These belong to different phyla.
$4$. Option $D$: Malarial parasite (Protozoa),Amoeba (Protozoa),Mosquito (Arthropoda). These belong to different phyla.
Therefore,the correct group is $B$.

(A) The phylum $Arthropoda$ includes animals with jointed appendages and a chitinous exoskeleton.
$Silverfish$ ($Lepisma$ $saccharina$) is a wingless insect belonging to the class $Insecta$ of the phylum $Arthropoda$.
$Pufferfish$ is a bony fish belonging to the phylum $Chordata$.
$Flying$ $fish$ $(Exocoetus)$ is a bony fish belonging to the phylum $Chordata$.
$Cuttlefish$ $(Sepia)$ is a mollusk belonging to the phylum $Mollusca$.
Therefore,the correct representative of $Arthropoda$ is $Silverfish$.

(B) In the phylum $Arthropoda$,vectors are organisms that transmit pathogens from one host to another.
$Anopheles$ is a genus of mosquitoes belonging to the phylum $Arthropoda$ and class $Insecta$.
$Anopheles$ mosquitoes act as vectors for the transmission of the malaria parasite $(Plasmodium)$.
$Locusta$ (locust) is a gregarious pest,and $Limulus$ (king crab) is a living fossil; neither acts as a disease vector.
Therefore,the correct option is $B$.

(D) The cockroach belongs to the phylum $Arthropoda$.
$Arthropoda$ is the largest phylum in the animal kingdom.
Key characteristics of $Arthropoda$ include jointed appendages,a chitinous exoskeleton,and a segmented body.
Cockroaches are specifically classified under the class $Insecta$ within the phylum $Arthropoda$.

(B) Ecdysis,also known as moulting,is the process of shedding the old exoskeleton or cuticle in arthropods and some other invertebrates.
In these organisms,the outer layer of the body,which is the epidermis (specifically the cuticle secreted by the epidermis),must be shed to allow for growth.
Therefore,ecdysis is the shedding of the epidermis or its derivatives (cuticle).

(A) In the phylum $Arthropoda$,the body is typically divided into three regions: head,thorax,and abdomen.
In the class $Insecta$ (Hexapoda),the body is clearly segmented into these three distinct regions.
In contrast,many members of the classes $Crustacea$ and $Arachnida$ exhibit a fused head and thorax,known as a cephalothorax.

(A) Centipedes,cockroaches,and crabs all belong to the phylum $Arthropoda$.
Key characteristics of the phylum $Arthropoda$ include the presence of jointed appendages ($arthros$ = joint,$poda$ = foot) and a tough,protective chitinous exoskeleton.
Green glands are specific to some crustaceans,tracheae are found in insects and myriapods,and book lungs are found in arachnids,but jointed appendages and a chitinous exoskeleton are universal features across all these classes within the phylum $Arthropoda$.

(A) The correct answer is $A$.
$1$. In the phylum $Arthropoda$,the body is typically divided into head,thorax,and abdomen,and respiration occurs through specialized structures called tracheae.
$2$. In $Chordata$,while a notochord is present,the anus and reproductive tract do not always open into a common cloaca; this is specific to certain groups like amphibians or birds,not a general characteristic of the entire phylum.
$3$. $Echinodermata$ exhibit pentamerous radial symmetry in adults,but fertilization is primarily external,not internal.
$4$. While many $Mollusca$ are oviparous and have larval stages,option $A$ provides the most definitive and accurate anatomical description characteristic of the phylum $Arthropoda$.

(D) To determine the correct classification:
$A$. Ant-eater is a mammal,Sea-urchin and Sea-cucumber are Echinoderms. This set is incorrect.
$B$. Flying fish is a fish,Sepia is a Mollusc,and Silverfish is an insect. This set is incorrect.
$C$. Centipede,Millipede,Spider,and Scorpion are Arthropods but belong to different classes (Chilopoda,Diplopoda,Arachnida). They are not all insects. This set is incorrect.
$D$. Housefly,Butterfly,Tsetse fly,and Silverfish all belong to the class $Insecta$ of the phylum $Arthropoda$. This set is correct.

(C) The phylum $Arthropoda$ includes animals with jointed appendages and a chitinous exoskeleton.
$A$. Flying fish $(Exocoetus)$ belongs to the phylum $Chordata$ (Class: $Osteichthyes$).
$B$. Sepia (Cuttlefish) belongs to the phylum $Mollusca$ (Class: $Cephalopoda$).
$C$. Silverfish $(Lepisma)$ is an insect,which belongs to the phylum $Arthropoda$ (Class: $Insecta$).
$D$. Pufferfish belongs to the phylum $Chordata$ (Class: $Osteichthyes$).
Therefore,the correct option is $C$.

(D) To determine the correct group,let us analyze the phylum of each animal:
$A$. Sponge (Porifera),Sea Anemone (Cnidaria),Starfish (Echinodermata) - Different phyla.
$B$. Malarial parasite (Protozoa),Amoeba (Protozoa),Mosquito (Arthropoda) - Different phyla.
$C$. Earthworm (Annelida),Pinworm (Aschelminthes),Tapeworm (Platyhelminthes) - Different phyla.
$D$. Prawn (Arthropoda),Scorpion (Arthropoda),Locust (Arthropoda) - All belong to the phylum $Arthropoda$.
Therefore,the correct group is $D$.

(B) The phylum $Arthropoda$ is characterized by the presence of jointed appendages,a chitinous exoskeleton,and metameric segmentation (metamerism).
Parapodia are lateral appendages found in the phylum $Annelida$ (specifically in class $Polychaeta$,like $Nereis$),which are used for swimming and respiration.
Therefore,parapodia are not a characteristic feature of arthropods.

(C) Peripatus is a genus of velvet worms in the phylum Onychophora.
It exhibits characteristics of both the phylum $Annelida$ (such as segmented bodies,thin cuticle,and segmentally arranged nephridia) and the phylum $Arthropoda$ (such as tracheal respiration,open circulatory system,and jointed appendages).
Therefore,it serves as a living connecting link between $Annelida$ and $Arthropoda$.

(A) Ticks and mites belong to the class $Arachnida$ within the phylum $Arthropoda$. Other members of this class include scorpions and spiders,which are characterized by having four pairs of walking legs and lacking antennae.

(N/A) The phylum $Arthropoda$ consists of more than two-thirds of the animal species on Earth.
The reasons for the success of arthropods are as follows:
$1$. Jointed appendages allow for greater mobility and versatility on land.
$2$. $A$ hard exoskeleton made of $chitin$ provides structural support and protection against predators and environmental stress.
$3$. The waxy,hard exoskeleton significantly reduces water loss from the body,making them highly adapted to diverse terrestrial conditions.
$4$. They possess a variety of sensory organs and complex behavioral patterns that aid in survival.

(A) The image displays organisms belonging to the phylum $Arthropoda$ (Locust,Butterfly,Scorpion,and Prawn).
Key characteristics of phylum $Arthropoda$ include:
$1$. They have an organ-system level of body organization.
$2$. They are bilaterally symmetrical,triploblastic,segmented,and coelomate animals.
$3$. The body is covered by a chitinous exoskeleton.
$4$. The body consists of head,thorax,and abdomen.
$5$. They have jointed appendages (arthros = joint,poda = appendages).
$6$. Respiration takes place through gills,book gills,book lungs,or tracheal system.
$7$. Circulatory system is of open type.
$8$. Sensory organs like antennae,eyes (compound and simple),statocysts,or balance organs are present.
$9$. Excretion takes place through Malpighian tubules.
$10$. They are mostly dioecious,and fertilization is usually internal.

(N/A) $\rightarrow$ Arthropoda is the largest phylum of Animalia which includes insects.
$\rightarrow$ Over two-thirds of all named species on earth are arthropods.
$\rightarrow$ They have organ-system level of organisation.
$\rightarrow$ They are bilaterally symmetrical,triploblastic,segmented and coelomate animals.
$\rightarrow$ The body of arthropods is covered by chitinous exoskeleton.
$\rightarrow$ The body consists of head,thorax and abdomen.
$\rightarrow$ They have jointed appendages (arthros-joint,poda-appendages).
$\rightarrow$ Respiratory organs are gills,book gills,book lungs or tracheal system.
$\rightarrow$ Circulatory system is of open type.
$\rightarrow$ Sensory organs like antennae,eyes (compound and simple),statocysts or balance organs are present.
$\rightarrow$ Excretion takes place through malpighian tubules.
$\rightarrow$ They are mostly dioecious.
$\rightarrow$ Fertilisation is usually internal.
$\rightarrow$ They are mostly oviparous.
$\rightarrow$ Development may be direct or indirect.
$\rightarrow$ Examples: Economically important insects -
$\rightarrow$ Apis (Honey bee)
$\rightarrow$ Bombyx (Silkworm)
$\rightarrow$ Laccifer (Lac insect)

(A) An open circulatory system is a type of circulatory system where the blood is pumped into body cavities (hemocoel) and the tissues are bathed in blood directly. This type of circulatory system is characteristic of Arthropods and most Molluscs.

(N/A) $\rightarrow$ Arthropoda is the largest phylum of Kingdom Animalia,which includes insects.
$\rightarrow$ Over two-thirds of all named species on earth are arthropods.
$\rightarrow$ They exhibit an organ-system level of body organization.
$\rightarrow$ They are bilaterally symmetrical,triploblastic,segmented,and coelomate animals.
$\rightarrow$ The body of arthropods is covered by a chitinous exoskeleton.
$\rightarrow$ The body consists of a head,thorax,and abdomen.
$\rightarrow$ They possess jointed appendages (arthros = joint,poda = appendages).
$\rightarrow$ Respiratory organs include gills,book gills,book lungs,or a tracheal system.
$\rightarrow$ The circulatory system is of the open type.
$\rightarrow$ Sensory organs like antennae,eyes (compound and simple),and statocysts (balance organs) are present.
$\rightarrow$ Excretion takes place through Malpighian tubules.
$\rightarrow$ They are mostly dioecious.
$\rightarrow$ Fertilization is usually internal.
$\rightarrow$ They are mostly oviparous.
$\rightarrow$ Development may be direct or indirect.
$\rightarrow$ Examples of economically important insects:
$\rightarrow$ $Apis$ (Honey bee)
$\rightarrow$ $Bombyx$ (Silkworm)
$\rightarrow$ $Laccifer$ (Lac insect)

(D) The order $Coleoptera$ consists of insects commonly known as beetles.
$Tobacco$ $budworms$ and $armyworms$ belong to the order $Lepidoptera$.
$Mosquitoes$ belong to the order $Diptera$.
Therefore,$Beetles$ are the organisms that fall under the order $Coleoptera$.

(D) Arthropoda is the largest phylum in the animal kingdom.
Arthropods are characterized by several key features,including a bilaterally symmetrical body,being triploblastic,and having metamerically segmented bodies.
They possess jointed appendages,which is the defining characteristic of the phylum (the name Arthropoda is derived from 'arthros' meaning joint and 'poda' meaning foot).
Additionally,they have an open circulatory system where the blood flows into body cavities (hemocoel).
Since all the given options are correct features of Arthropoda,the correct answer is $D$.

(C) The exoskeleton of members of the phylum $Arthropoda$ is composed of a tough,chitinous cuticle.
This cuticle provides protection and support for the body.
As the organism grows,it must periodically shed this exoskeleton in a process known as $ecdysis$ or molting to allow for further growth and development.

(A) Scorpion belongs to the class $Arachnida$ of the phylum $Arthropoda$.
Ticks also belong to the class $Arachnida$.
Crabs belong to the class $Crustacea$.
Cockroaches belong to the class $Insecta$.
Therefore,the correct answer is ticks.

(D) Phylum-$Arthropoda$ is the largest phylum of the animal kingdom,accounting for over two-thirds of all named species on Earth.
Phylum-$Mollusca$ is the second largest phylum in the animal kingdom.

(C) White ants,also known as termites,are social,colonial,and polymorphic insects. They live in highly organized colonies with a division of labor among different castes such as workers,soldiers,and reproductives.

(D) Book lungs are specialized respiratory organs found in arachnids like scorpions.
Book gills are specialized respiratory structures found in aquatic arthropods like king crabs (Limulus).

(D) In mosquitoes and other Dipteran insects,the metathorax bears a pair of small,club-shaped structures known as $Halteres$. These organs act as gyroscopic sensors that help in maintaining balance during flight. While they are primarily sensory organs for stabilization,in some species,they are also associated with the production of the characteristic buzzing sound heard during flight.

(D) The classification of insects is based on their morphological characteristics and evolutionary history.
$1$. $Lepidoptera$: This order includes butterflies and moths,characterized by wings covered with tiny scales.
$2$. $Hemiptera$: This order includes true bugs,such as $Cimex$ (bed bug).
$3$. $Homoptera$: This order includes insects like $Aphis$ (aphids).
Therefore,the butterfly belongs to the order $Lepidoptera$.

(B) The members of phylum-$Arthropoda$ exhibit bilateral symmetry,three germ layers in the body wall,external metamerism,jointed and paired appendages,a haemocoel,and an open type of circulatory system with a dorsal heart.

(B) Phylum-$Arthropoda$ is the largest phylum of the animal kingdom.
It includes about $900,000$ species found in all types of habitats.
These species constitute approximately $70 \%$ of all the known animal species on Earth.

(A) $Scorpion$ $(Arachnida)$,$cockroach$ $(Insecta)$,and $silver$ $fish$ $(Insecta)$ all belong to the phylum $Arthropoda$.
$Arthropods$ are characterized by the presence of jointed appendages,which is a defining feature of this phylum.
Therefore,the statement that they all have jointed paired appendages is correct.

(B) Class-$Crustacea$ includes organisms such as $Daphnia$,crab,prawn,lobster,and shrimp.
Millipede (e.g.,$Julus$) belongs to the class-$Diplopoda$.
Centipede (e.g.,$Scolopendra$) belongs to the class-$Chilopoda$.
Therefore,millipede and centipede are the animals that do not belong to class-$Crustacea$.

(D) Animals belonging to class-$Crustacea$ (a subphylum of $Arthropoda$) typically respire through their body surface or specialized respiratory organs known as gills.
Excretion in these organisms is primarily carried out by specialized structures called antennal glands,which are also known as green glands.
Therefore,the characteristic features for respiration and excretion in $Crustacea$ are gills and antennal glands.

(C) The phylum Arthropoda is characterized by jointed appendages and a chitinous exoskeleton.
Among the given options,lobsters,spiders,and shrimps all belong to the phylum Arthropoda.
Cuttlefish (Mollusca),jellyfish (Cnidaria),and silverfish (Arthropoda) are a mixed group.
Bats (Mammalia),pigeons (Aves),and kites (Aves) are Chordates.
Oysters (Mollusca),otters (Mammalia),and octopuses (Mollusca) are also not all Arthropods.

(C) The incorrect statement is $(c)$.
Arthropods are triploblastic animals,not diploblastic.
While it is true that their body is divided into head,thorax,and abdomen,the classification of them as diploblastic is scientifically incorrect.