Phylum-Echinodermata Questions in English

(C) Arms are absent in the class $Echinoidea$ (e.g.,sea urchins) and class $Holothuroidea$ (e.g.,sea cucumbers).
In $Echinodermata$,the body plan varies significantly.
Sea urchins belong to $Echinoidea$,which are globular or disc-shaped and lack arms.
Sea cucumbers belong to $Holothuroidea$,which are elongated and also lack arms.

(C) The phylum $Echinodermata$ includes marine animals characterized by a water vascular system and radial symmetry in adults.
$A$. Sea lily $(Antedon)$ belongs to the class $Crinoidea$ of the phylum $Echinodermata$.
$B$. Sea cucumber $(Cucumaria)$ belongs to the class $Holothuroidea$ of the phylum $Echinodermata$.
$C$. Sea hare $(Aplysia)$ belongs to the class $Gastropoda$ of the phylum $Mollusca$,not $Echinodermata$.
$D$. Sea urchin $(Echinus)$ belongs to the class $Echinoidea$ of the phylum $Echinodermata$.
Therefore,the correct answer is $C$.

(D) Echinoderms possess an endoskeleton (internal skeleton) composed of calcareous ossicles (small bony plates),which are embedded within the dermis of the skin.
This endoskeleton is derived from the mesoderm during embryonic development.

(B) $Asterias$ (starfish) belongs to the phylum $Echinodermata$.
Echinoderms are free-living marine animals.
Adult echinoderms exhibit radial symmetry, whereas their larval stages exhibit bilateral symmetry.
These larval stages are also free-swimming in nature.
Therefore, both statements $(b)$ and $(c)$ are correct.

(D) The water vascular system is the most distinctive feature of $Echinoderms$.
This system plays a vital role in locomotion,the capture and transport of food,respiration,and excretion.

(B) The water vascular system is a characteristic feature of the phylum $Echinodermata$.
In echinoderms,a specialized excretory system is absent.
The excretory products diffuse out from the body tissues into the coelomic fluid,from where the waste is eliminated out of the body.

(A) The water vascular system is a characteristic feature of the phylum $Echinodermata$.
Tube feet are an essential component of the water vascular system in echinoderms,which helps in locomotion,capture of food,and respiration.
Star fish $(Asterias)$ is a well-known member of the phylum $Echinodermata$,and therefore,it possesses tube feet.

(B) Assertion is true: Echinoderms are the only radially symmetrical animals that possess a true coelom.
Reason is also true: Echinoderms exhibit secondary radial symmetry. This means that their larval stages are bilaterally symmetrical,but they develop radial symmetry as adults.
Conclusion: While both statements are scientifically accurate,the fact that they adapted to radial symmetry secondarily does not explain why they are the only radially symmetrical animals with a true coelom. Therefore,the Reason is not the correct explanation for the Assertion.

(B) In the phylum $Echinodermata$, the adult organisms exhibit $radial$ $symmetry$ (specifically $pentamerous$ $radial$ $symmetry$), whereas the larval stages exhibit $bilateral$ $symmetry$. This is a characteristic feature of this phylum.

(C) The phylum $Echinodermata$ is characterized by a unique feature where the larvae exhibit bilateral symmetry,while the adults exhibit radial symmetry (specifically pentamerous radial symmetry). This transition occurs during metamorphosis.

(C) The water vascular system is a unique and diagnostic feature of the phylum $Echinodermata$. This system consists of a network of fluid-filled canals that play a crucial role in locomotion,capture and transport of food,and respiration.

(B) The correct matches for the given animals in the phylum Echinodermata are as follows:
$P$. Starfish is $Asterias$ $(IV)$.
$Q$. Sea urchin is $Echinus$ $(II)$.
$R$. Sea lily is $Antedon$ $(I)$.
$S$. Sea cucumber is $Cucumaria$ $(III)$.
$T$. Brittle star is $Ophiura$ $(V)$.
Therefore, the correct sequence is $(P-IV), (Q-II), (R-I), (S-III), (T-V)$.

(C) The water vascular system is a unique characteristic of the phylum $Echinodermata$.
Its primary functions include:
$1$. Locomotion (movement using tube feet).
$2$. Capture and transport of food.
$3$. Respiration (gas exchange).
Reproduction is $NOT$ a function of the water vascular system; it is a separate physiological process involving the reproductive organs (gonads).

(C) The organism shown in the image is a starfish (Asterias),which belongs to the phylum Echinodermata.
Key characteristics of Echinoderms include:
$1$. They are exclusively marine.
$2$. They possess a unique water vascular system,which helps in locomotion,capture and transport of food,and respiration.
$3$. They are triploblastic (derived from three germ layers).
$4$. They are coelomates (possess a true body cavity).
Therefore,the statement 'Acoelomate' is incorrect because Echinoderms are coelomate animals.

(B) The water vascular system is a unique characteristic of the phylum Echinodermata.
It plays a crucial role in multiple physiological processes.
Specifically,it is involved in locomotion (via tube feet),respiration (gas exchange across the tube feet/dermal branchiae),and the capture and transport of food.
Therefore,the functions listed in $A$ (Respiration and Locomotion) and $C$ (Capture and transport of food) are correct.
Thus,the correct option is $A$ and $C$ only.

(A) The correct matching is as follows:
$A$. Asterias is commonly known as Star fish $(IV)$
$B$. Antedon is commonly known as Sea lily $(III)$
$C$. Echinus is commonly known as Sea urchin $(I)$
$D$. Ophiura is commonly known as Brittle star $(II)$
Therefore,the correct sequence is $A-IV, B-III, C-I, D-II$.

(A) The correct matches for the given organisms belonging to Phylum Echinodermata are as follows:
$(i)$ Asterias is commonly known as Star fish.
$(ii)$ Echinus is commonly known as Sea urchin.
$(iii)$ Antedon is commonly known as Sea lily.
$(iv)$ Ophiura is commonly known as Brittle star.
Therefore, the correct matching sequence is $i-d, ii-c, iii-b, iv-a$.

(D) The phylum $Echinodermata$ is characterized by the following features:
$1$. They possess an endoskeleton of calcareous ossicles,which is why they are named $Echinodermata$ (spiny-skinned).
$2$. They are exclusively marine organisms.
$3$. $A$ unique feature of this phylum is the presence of a water vascular system,which helps in locomotion,capture and transport of food,and respiration.
Since all the given statements are correct,the correct option is $D$.

(D) The organism that exhibits triploblastic,coelomate,complete digestive system,and radial symmetry is $Echinus$ (a member of the phylum $Echinodermata$).
$1$. $Periplaneta$ (cockroach) is triploblastic,coelomate,and has a complete digestive system,but it exhibits bilateral symmetry.
$2$. $Fasciola$ (liver fluke) is triploblastic,acoelomate,and exhibits bilateral symmetry.
$3$. $Pila$ (snail) is triploblastic,coelomate,and exhibits bilateral symmetry.
$4$. $Echinus$ (sea urchin) is triploblastic,coelomate,has a complete digestive system,and exhibits radial symmetry (specifically pentamerous radial symmetry in adults).

(B) The water vascular system is a unique characteristic feature of the phylum $Echinodermata$.
$Antedon$ (commonly known as feather star) belongs to the phylum $Echinodermata$.
$Sycon$ belongs to the phylum $Porifera$.
$Balanoglossus$ belongs to the phylum $Hemichordata$.
$Loligo$ belongs to the phylum $Mollusca$.
Therefore,the correct answer is $Antedon$.

(D) The correct answer is $D$.
In the phylum $Echinodermata$,adult animals exhibit radial symmetry,while their larval stages exhibit bilateral symmetry.
This transition in symmetry from bilateral in the larval stage to radial in the adult form is a characteristic feature of echinoderms.
In contrast,$Annelids$,$Arthropods$,and $Molluscs$ exhibit bilateral symmetry throughout their life cycles.

(A) The correct answer is $A$.
In the phylum $Echinodermata$,adult animals exhibit radial symmetry,while their larval stages show bilateral symmetry.
This transition from bilateral symmetry in the larval stage to radial symmetry in the adult form is a unique and characteristic feature of echinoderms.