Q1. Which subphylum of chordates includes animals with a notochord present only in the embryonic stage?
a) Urochordata
b) Cephalochordata
c) Vertebrata
d) Hemichordata
Show Answer
Correct Answer: a) Urochordata
Explanation: Urochordates, also known as tunicates or sea squirts, possess a notochord only during the larval stage, which is lost in adulthood. They are filter-feeding marine organisms characterized by a sac-like body enclosed in a tough outer covering called a tunic.
Q2. Animals in the subphylum Cephalochordata are commonly known as:
a) Sea squirts
b) Hagfish
c) Lancelets
d) Lampreys
Show Answer
Correct Answer: c) Lancelets
Explanation: Cephalochordates, or lancelets, are small, fish-like marine organisms with a notochord extending along the entire length of their body. They possess a primitive vertebral column and are filter feeders, burrowing in sand with only their head protruding.
Q3. The subphylum Vertebrata includes animals characterized by the presence of:
a) A notochord
b) Pharyngeal gill slits
c) A dorsal nerve cord
d) A vertebral column
Show Answer
Correct Answer: d) A vertebral column
Explanation: Vertebrates, belonging to the subphylum Vertebrata, possess a vertebral column, also known as a backbone or spine, which provides support and protection for the spinal cord. This feature distinguishes vertebrates from other chordates.
Q4. Which of the following is a characteristic feature of animals in the subphylum Vertebrata?
a) Exoskeleton
b) Internal gills
c) Jointed appendages
d) Endoskeleton
Show Answer
Correct Answer: d) Endoskeleton
Explanation: Vertebrates possess an endoskeleton, consisting of bones or cartilage, which provides structural support and protection for internal organs. The endoskeleton also serves as attachment sites for muscles, allowing for movement and locomotion.
Q5. The class Agnatha within the subphylum Vertebrata includes animals characterized by:
a) Cartilaginous skeleton
b) Bony skeleton
c) Presence of jaws
d) Lack of jaws
Show Answer
Correct Answer: d) Lack of jaws
Explanation: Agnathans, such as lampreys and hagfish, are jawless vertebrates belonging to the class Agnatha. They possess a cartilaginous skeleton, lack paired fins, and have a circular, sucking mouth used for feeding.
Q6. Which class within the subphylum Vertebrata includes animals with a skeleton primarily composed of cartilage?
a) Chondrichthyes
b) Osteichthyes
c) Amphibia
d) Reptilia
Show Answer
Correct Answer: a) Chondrichthyes
Explanation: Chondrichthyans, or cartilaginous fish, belong to the class Chondrichthyes
within the subphylum Vertebrata. They possess a skeleton primarily composed of cartilage, rather than bone. Examples include sharks, rays, and skates, which inhabit marine environments worldwide.
Q7. Animals in the class Osteichthyes are characterized by the presence of:
a) Scales and fins
b) Bony skeleton
c) Gills for respiration
d) All of the above
Show Answer
Correct Answer: d) All of the above
Explanation: Osteichthyans, or bony fish, possess scales and fins, a bony skeleton, and gills for respiration. They are the most diverse group of vertebrates, inhabiting freshwater and marine environments worldwide, and include familiar fish species such as trout, salmon, and bass.
Q8. Which class within the subphylum Vertebrata includes animals capable of both terrestrial and aquatic respiration?
a) Amphibia
b) Reptilia
c) Aves
d) Mammalia
Show Answer
Correct Answer: a) Amphibia
Explanation: Amphibians, belonging to the class Amphibia, are vertebrates capable of both terrestrial and aquatic respiration. They typically undergo metamorphosis from aquatic larvae to terrestrial adults and include frogs, toads, salamanders, and newts.
Q9. The class Reptilia within the subphylum Vertebrata includes animals characterized by:
a) Mammary glands
b) Oviparous reproduction
c) Endothermy
d) Feathers
Show Answer
Correct Answer: b) Oviparous reproduction
Explanation: Reptiles, belonging to the class Reptilia, reproduce by laying eggs, making them oviparous. They are ectothermic, meaning they rely on external sources of heat for thermoregulation. Reptiles include snakes, lizards, turtles, crocodiles, and tuataras.
Q10. Animals in the class Aves within the subphylum Vertebrata are characterized by the presence of:
a) Feathers and beaks
b) Mammary glands
c) Internal fertilization
d) Viviparous reproduction
Show Answer
Correct Answer: a) Feathers and beaks
Explanation: Birds, belonging to the class Aves, are characterized by feathers and beaks, which are adaptations for flight and feeding. They possess a lightweight skeleton, efficient respiratory system, and endothermy, enabling them to maintain high body temperatures even during flight.