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5.7 Metamorphosis — Test 1
Q1. Amphibian metamorphosis (e.g. tadpole to frog) is mainly controlled by:✓ Thyroid hormone
Q2. Axolotl neoteny (retaining larval gills as an adult) is due to:✓ Lack of pituitary/thyroid stimulation, so low thyroid hormone
Q3. Retention of larval or embryonic characters in the sexually mature adult is called:✓ Neoteny
Q4. Retrogressive metamorphosis, where the larva is more advanced than the adult, occurs in:✓ Urochordates (tunicates)
Q5. Insect metamorphosis is regulated by the balance between ecdysone and:✓ Juvenile hormone
Q6. Complete metamorphosis (holometaboly), with egg-larva-pupa-adult, occurs in insects such as:✓ Beetles, flies and butterflies
Q7. In holometabolous insects, the adult structures form at metamorphosis from:✓ Imaginal discs set aside in the larva
Q8. In amphibian metamorphosis, thyroid hormone causes the tadpole tail to:✓ Be resorbed by programmed cell death
Q9. A defining feature of metamorphosis is that it involves:✓ A marked, hormonally controlled change in body form between larva and adult
Q10. The same hormone can cause opposite responses in different tissues during metamorphosis. In the frog, thyroid hormone makes the tail die but the:✓ Limbs grow
Q11. Temperature, nutrition and hormones that influence post-embryonic development show that development is:✓ Influenced by environmental as well as genetic factors
Q12. Iodine deficiency can block amphibian metamorphosis because iodine is needed to make:✓ Thyroid hormone
Q13. In amphibian metamorphosis, thyroid hormone production is ultimately stimulated by which gland via TSH?✓ The pituitary gland
Q14. During frog metamorphosis, the gut is remodelled because the herbivorous tadpole becomes a:✓ Carnivorous frog needing a shorter gut
Q15. The appearance of limbs and resorption of the tail in a tadpole are triggered by:✓ A rise in thyroid hormone
Q16. Adding thyroxine to axolotl water can induce it to metamorphose, proving that its neoteny is due to:✓ A deficiency of thyroid-hormone stimulation, not an inability to respond
5.7 Metamorphosis — Test 2
Q17. In insects, moulting (ecdysis) is triggered by the steroid hormone:✓ Ecdysone
Q18. Juvenile hormone (JH) in insects acts to:✓ Maintain larval features during a moult
Q19. A larval moult occurs when ecdysone acts in the presence of:✓ High juvenile hormone
Q20. The adult moult (to the imago) occurs when ecdysone acts with:✓ Little or no juvenile hormone
Q21. Holometabolous insects pass through which sequence of stages?✓ Egg → larva → pupa → adult
Q22. Hemimetabolous insects (e.g. grasshoppers) differ in that they:✓ Lack a pupal stage; nymphs gradually become adults
Q23. During pupation, the adult structures of a fly are built from clusters of cells set aside in the larva called:✓ Imaginal discs
Q24. The fact that thyroid hormone causes the tail to die but the limbs to grow shows that:✓ Different tissues respond differently to the same hormone
Q25. Apoptosis (programmed cell death) during amphibian metamorphosis is responsible for:✓ Resorption of the tadpole tail and gills
Q26. In some animals, sex or caste is determined by environmental factors during development, showing:✓ Developmental plasticity (environment can shape development)
Q27. In honeybees, whether a female larva becomes a queen or worker is determined largely by:✓ Diet (royal jelly)
Q28. Metamorphosis often accompanies a change in habitat, for example a frog moving from:✓ Water (tadpole) to land (adult)
Q29. The replacement of gills by lungs during amphibian metamorphosis is an example of:✓ Coordinated remodelling driven by thyroid hormone
Q30. Why is amphibian metamorphosis a favourite model for studying hormone action?✓ A single hormone (thyroid) triggers dramatic, well-defined tissue changes
Q31. Direct development (no larval stage), as in some frogs, shows that metamorphosis can be:✓ Modified or lost during evolution
Q32. Overall, post-embryonic development and metamorphosis demonstrate that an animal's body plan can be:✓ Remodelled after embryogenesis under hormonal control