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Courses on the invertebrates have two principal aims: (1) to introduce students to the diversity of animal life and (2) to make them aware that organisms are marvellously integrated systems with evolutionary pasts and ecological presents. This text is concerned exclusively with the second aim and assumes that the reader will already know something about the diversity and classification of invertebrates. Concepts of whole-organism function, metabolism and adaptation form the core of the subject-matter and this is also considered in an ecological setting. Hence, the approach is multi-disciplinary, drawing from principles normally restricted to comparative morphology and physiology, ecology and evolutionary biology. Invertebrate courses, as with all others in a science curriculum, also have another aim - to make students aware of the general methods of science. And these I take to be associated with the so-calledhypothetico deductive programme. Here, therefore, I make a conscious effort to formulate simple, some might say naive, hypotheses and to confront them with quantitative data from the real world. There are, for example, as many graphs in the book as illustrations of animals. My aim, though, has not been to test out the principles of Darwinism, but rather to sharpen our focus on physiological adaptations, given the assumption that Darwinism is approximately correct. Whether or not I succeed remains for the reader to decide.
List of contents
1. Introduction.- 1.1 Functional Biology - What is It?.- 1.2 The Invertebrates.- 1.3 The Physiological Approach.- 1.4 Physiology and Fitness.- 1.5 The Last Word on Genetics.- 2. Acquisition.- 2.1 Why Feed?.- 2.2 What is Eaten and How?.- 2.3 Detailed Consideration of What Should Be Eaten.- 2.4 How Much to Eat.- 2.5 Gut Form and Function.- 2.6 Digestibility.- 2.7 Movement of Food Through the Gut.- 2.8 Control.- 3. Respiration.- 3.1 Molecular Basis.- 3.2 Oxygen Availability and Uptake.- 3.3 Levels of Metabolism.- 3.4 Routine Metabolism and the Effect of Body Size.- 3.5 Metabolism Associated with Feeding.- 3.6 Active Metabolism.- 3.7 Effect of Temperature.- 4. Excretion.- 4.1 What is It?.- 4.2 The 'Excretory System'.- 4.3 Energy Costs and Benefits.- 4.4 Secretions.- 5. Growth.- 5.1 Introduction.- 5.2 Metabolic Basis.- 5.3 Distribution of limited and Unlimited Growth.- 5.4 Cellular Basis.- 5.5 Adaptational Aspects.- 5.6 On When to Stop Growing.- 5.7 Storage as a Special Kind of Growth.- 5.8 Allometric Growth.- 5.9 On Growth and Ageing.- 5.10 On Degrowth and Rejuvenation.- 6. Reproduction.- 6.1 Introduction.- 6.2 Sexual Gamete Production, Fertilisation and Early Development.- 6.3 Marine life-cycles and the Trade-off Between Egg Size and Numbers.- 6.4 Eggs of Terrestrial and Freshwater Invertebrates.- 6.5 The Complex Insect life-cycle.- 6.6 The Cost of Reproduction For Parental Survival (Iteroparity v. Semelparity).- 6.7 Reproduction Without Sex.- 7. Integration.- 7.1 Why the Holistic Approach is Important.- 7.2 The Energy Budget as an Integrating Equation.- 7.3 Scope for Growth in Mytilus.- 7.4 Integration Under Temperature Stress.- 7.5 Integration Under Food Stress.- 7.6 Modelling Metabolism.- References.- Glossary of Symbols.- Index of Organisms.
