Metamorphosis: A Problem in Developmental Biology

'1 Metamorphosis: An Overview.- 1. Introduction.- 2. Primacy of the Spawning Environment.- 3. Internal or External Salinity-Which Determines the Visual Pattern?.- 4. Euryhaline Fishes and Amphibians.- 5. Biochemistry of Metamorphosis.- 6. Second Metamorphosis.- 7. Deep-Sea Fishes; Eels.- 8. Land Vertebrates.- 9. Conclusion.- 10. Epilogue.- References.- I: Insects.- 2 A Survey of Invertebrate Metamorphosis.- 1. Introduction.- 2. Invertebrate Metamorphoses.- 2.1. Porifera.- 2.2. Cnidaria.- 2.3. Ctenophora.- 2.4. Platyhelminthes.- 2.5. Nemertinea.- 2.6. Acanthocephala.- 2.7. Aschelminthes.- 2.8. Rotifera.- 2.9. Kinorhyncha.- 2.10. Priapulida.- 2.11. Entoprocta.- 2.12. Polyzoa.- 2.13. Brachiopoda.- 2.14. Annelida.- 2.15. Sipunculida.- 2.16. Echiurida.- 2.17. Arthropoda.- 2.18. Mollusca.- 2.19. Echinodermata.- 2.20. Phoronidea.- 2.21. Chaetognatha.- 2.22. Hemichordata.- 3. Comparison of Insect Metamorphosis with That of Other Invertebrates.- 3.1. Ametabolous Development.- 3.2. Hemimetabolous Development.- 3.3. Holometabolous Development.- 3.4. Hypermetamorphosis.- 4. Control of Metamorphosis.- 4.1. Larval Settlement and Metamorphosis.- 4.2. The Timing of Metamorphosis.- 5. Conclusions.- References.- 3 Cell Structure during Insect Metamorphosis.- 1. Introduction.- 1.1. The Nature of Metamorphosis.- 1.2. Definition of Terms.- 2. Tissue Reorganization.- 2.1. Metamorphic Changes in the Arrangement of Cells in Lepidopteran Fat Body.- 2.2. Changes in the Location of Cells-Epidermal and Muscle Rearrangement.- 2.3. Changes in Composition and the Distribution of Reserves.- 3. Cell Remodeling.- 3.1. The General Mechanism of Autophagy.- 3.2. Repopulation with New Organelles.- 3.3. Membrane Changes and Membrane Turnover.- 3.4. The Cytoskelton and Changes in Shape and Organelle Distribution.- 3.5. Cell Coupling and Junctions.- 3.6. The Control of Remodeling.- 4. Changes in the Numbers and Kinds of Cells in Remodeling to Make New Tissues.- 4.1. Cell Division.- 4.2. Cell Death.- 4.3. Polyploidy and Polyteny.- 5. The Morphology Needed to Explain Some Aspects of Metamorphosis.- 5.1. Hormonal Signals and the Response of the Nucleus.- 5.2. Positional Signals and the Kind and Amount of Growth.- 5.3. The Reception and Use of Nutritional and Precursor Molecules: Pinocytosis and Transepithelial Transport.- 6. Discussion.- 6.1. The Onset of Metamorphosis.- 6.2. Comparisons between Insects and Vertebrates.- References.- 4 Hormonal Control of Insect Metamorphosis.- 1. Introduction.- 2. Classical Methods for the Study of the Endocrinology of Insect Metamorphosis.- 3. The Insect Endocrine System: Structural Components of the Classical Scheme.- 3.1. The Brain-Neurosecretory Cells.- 3.2. Neurohemal Organs.- 3.3. Prothoracic Glands.- 3.4. Corpora Allata.- 4. Studies Leading to the Elaboration of the Classical Scheme.- 5. Chemistry and Endocrinology of the Metamorphic Hormones.- 5.1. Brain Hormone.- 5.2. Molting Hormones (Ecdysteroids).- 5.3. Juvenile Hormones.- 6. Control of Endocrine Glands.- 6.1. Cerebral NSC.- 6.2. The PG.- 6.3. The CA.- 7. Summary.- References.- 5 Chemistry, Metabolism, and Transport of Hormones Controlling Insect Metamorphosis.- 1. Introduction.- 2. Prothoracicotropic Hormone.- 3. Molting Hormone.- 3.1. Ecdysteroids-Chemistry and Occurrence.- 3.2. Biosynthesis of Ecdysone and 20-Hydroxyecdysone.- 3.3. Ecdysteroid Transport.- 3.4. Ecdysteroid Degradation.- 4. Juvenile Hormones.- 4.1. Chemistry and Occurrence.- 4.2. Structure-Activity Relationships.- 4.3. Transport.- 4.4. Biosynthesis.- 4.5. Degradation.- References.- 6 Macromolecular Changes during Insect Metamorphosis.- 1. Introduction.- 2. Changes in Protein and RNA during Larval-Pupal-Adult Metamorphosis.- 2.1. Breakdown of Macromolecular Components.- 2.2. Synthesis of Macromolecular Components.- 2.3. Cuticular Proteins.- 3. Pupal-Adult Metamorphosis: Wing Development.- 4. Larval-Pupal Metam