Comparative Endocrine Systems Practice Questions
20 free Comparative Endocrine Systems practice questions for the NCERT Biology. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
Which group of animals lacks specialized endocrine glands and relies mainly on neurosecretory cells for hormonal regulation?
- A Annelids
- B Arthropods
- C Cnidarians
- D Vertebrates
Correct answer: Cnidarians
Cnidarians do not possess distinct endocrine glands. They rely on neurosecretory cells that release chemical messengers for coordination.
In insects, the hormone responsible for regulating molting and metamorphosis is:
- A Juvenile hormone
- B Ecdysone
- C Insect insulin
- D Invertebrate thyroxine
Correct answer: Ecdysone
Ecdysone triggers molting in insects. Its interaction with juvenile hormone determines the nature of metamorphosis.
Juvenile hormone in insects is secreted by the:
- A Prothoracic glands
- B Corpora cardiaca
- C Corpora allata glands
- D Malpighian tubules
Correct answer: Corpora allata glands
Corpora allata secrete juvenile hormone. This hormone maintains larval characteristics and inhibits metamorphosis.
Which endocrine gland is unique to vertebrates and absent in invertebrates?
- A Adrenal gland
- B Thyroid gland
- C Pituitary gland
- D Pineal gland
Correct answer: Thyroid gland
The thyroid gland is a characteristic endocrine gland of vertebrates. It produces iodinated hormones like thyroxine.
Which hormone shows functional similarity in insects and vertebrates for regulating metabolism?
- A Ecdysone and cortisol
- B Juvenile hormone and growth hormone
- C Adipokinetic hormone and glucagon
- D Melatonin and prolactin
Correct answer: Adipokinetic hormone and glucagon
Adipokinetic hormone in insects mobilizes energy reserves. It is functionally similar to glucagon in vertebrates.
The endocrine regulation in annelids is mainly controlled by:
- A Discrete endocrine glands
- B Neurosecretory cells
- C Endocrine pancreas cells
- D Adrenal cortex tissue
Correct answer: Neurosecretory cells
Annelids rely largely on neurosecretory cells. These cells release hormones directly into body fluids.
Which hormone controls color change in crustaceans?
- A Ecdysone (moulting hormone)
- B Melatonin (pineal hormone)
- C Chromatophorotropin
- D Juvenile hormone (JH)
Correct answer: Chromatophorotropin
Chromatophorotropins regulate pigment movement in chromatophores. This enables color change in crustaceans.
The corpora cardiaca in insects primarily function as:
- A Sites of primary hormone synthesis and secretion
- B Storage and release centers for hormones
- C Digestive glands for enzyme production
- D Excretory organs filtering waste products
Correct answer: Storage and release centers for hormones
Corpora cardiaca store and release hormones produced by neurosecretory cells. They act as neurohemal organs.
Which endocrine feature is common to both insects and vertebrates?
- A Presence of thyroid gland
- B Hormonal regulation of growth
- C Use of iodinated hormones
- D Pituitary gland dominance
Correct answer: Hormonal regulation of growth
Both insects and vertebrates regulate growth through hormones. However, the hormones and glands involved differ.
Which hormone regulates carbohydrate metabolism in vertebrates but has no direct counterpart in insects?
- A Insulin (blood glucose–lowering)
- B Glucagon
- C Adipokinetic hormone
- D Ecdysone
Correct answer: Insulin (blood glucose–lowering)
Insulin is a vertebrate hormone that lowers blood glucose levels. Insects use different hormones for energy regulation.
The endocrine system becomes more complex with evolution primarily due to:
- A Increase in overall body size and mass
- B Development of specialized glands
- C Reduction in nervous system control
- D Loss of neurosecretory cell function
Correct answer: Development of specialized glands
Evolution led to the formation of specialized endocrine glands. This allowed precise and diversified hormonal control.
Which vertebrate group shows the earliest appearance of a well-developed endocrine system?
- A Cyclostomes
- B Bony fishes
- C Amphibians
- D Reptiles
Correct answer: Cyclostomes
Cyclostomes show early development of endocrine glands like pituitary and thyroid. They represent primitive vertebrates.
Which hormone is involved in metamorphosis in both amphibians and insects?
- A Thyroxine and ecdysone
- B Insulin and glucagon
- C Growth hormone and juvenile hormone
- D Prolactin and melatonin
Correct answer: Thyroxine and ecdysone
Thyroxine controls metamorphosis in amphibians, while ecdysone does so in insects. Both regulate developmental transitions.
Endocrine control in invertebrates is generally characterized by:
- A Rapid, short-lived hormonal effects
- B Highly centralized glandular regulation
- C Diffuse and simple organization
- D Exclusive glandular secretion only
Correct answer: Diffuse and simple organization
Invertebrate endocrine systems are relatively simple and diffuse. They often involve neurosecretory cells rather than discrete glands.
Which hormone is secreted by the vertebrate adrenal medulla but has a similar stress-related role in insects?
- A Cortisol
- B Adrenaline
- C Ecdysone
- D Juvenile hormone
Correct answer: Adrenaline
Adrenaline mediates stress responses in vertebrates. In insects, analogous neurohormones perform similar emergency functions.
The main endocrine glands regulating reproduction are best developed in:
- A Cnidarians
- B Annelid worms
- C Arthropods
- D Vertebrates
Correct answer: Vertebrates
Vertebrates have highly specialized gonads and pituitary control. This allows precise hormonal regulation of reproduction.
Which endocrine organ in insects is functionally similar to the vertebrate pituitary gland?
- A Corpora allata
- B Prothoracic gland
- C Corpora cardiaca
- D Malpighian tubules
Correct answer: Corpora cardiaca
Corpora cardiaca act as neuroendocrine centers. They release hormones that influence multiple physiological processes.
Which statement best describes comparative endocrine systems across animals?
- A All animals have identical endocrine glands
- B Complexity increases from invertebrates to vertebrates
- C Invertebrates lack hormonal regulation
- D Endocrine control replaces nervous control in evolution
Correct answer: Complexity increases from invertebrates to vertebrates
Endocrine systems become more complex with evolutionary advancement. Vertebrates show the highest degree of specialization.
Which hormone is absent in fishes but present in amphibians onward?
- A Thyroxine
- B Insulin
- C Aldosterone
- D Growth hormone
Correct answer: Aldosterone
Aldosterone is associated with terrestrial adaptation. It is absent in fishes but present in amphibians and higher vertebrates.
The primary advantage of advanced endocrine systems in vertebrates is:
- A Rapid reflex actions
- B Precise long-term regulation
- C Replacement of nervous system
- D Reduction in energy use
Correct answer: Precise long-term regulation
Advanced endocrine systems allow sustained and precise regulation of body functions. This supports complex physiology in vertebrates.