Understanding body shapes of animals : shapes as mechanical constructions and systems moving on minimal energy level

Preface Why This Book? Contents Chapter 1: Introduction: General Considerations, Working Hypotheses, Questions, and Starting Points 1.1 Basic Facts and Accepted Results 1.1.1 Tissues 1.1.2 Basic Mechanics 1.2 Animals in Focus: Vertebrates or Craniota 1.3 Some not so Common Aspects of Commonly Known Facts: What About Growing Big? 1.4 Essentials of Chapter 1 Chapter 2: Head: What Is Making First Contact with Environment? Teeth and Jaws 2.1 Teeth 2.1.1 Selachian Teeth 2.1.2 Fixation of Teeth 2.1.3 Teleost and Reptilian Teeth 2.1.4 Mammalian Teeth 2.2 Jaws 2.2.1 Lower Jaw 2.2.2 Upper Jaw, Nasal Cavity and Neural Cranium 2.2.3 Head as a Link, Jugal Arches and Lateral Snapping 2.2.4 Suction Feeding 2.2.5 Finite Element Systems Analysis and Finite Element Systems Synthesis 2.2.6 Does Skull Shape Obey the Same Rules as the Locomotor Apparatus? Development of Shape in Ontogeny in a Marsupial (Monode... 2.3 General Conclusions Concerning Tooth and Head Morphology Chapter 3: Axial Skeleton in Aquatic Animals 3.1 Definitions, Existence of Vertebrates (Including Agnatha) in Phylogeny 3.2 Why an Axial Skeleton? 3.2.1 Continuous Propulsion by Undulatory Movements Required in a Viscous Medium 3.2.2 Undulation Restricted to the Fluke: The Example of Rapid Epipelagic Swimmers 3.3 Common Morphological Characters Depending upon Mechanical Necessities 3.3.1 Location of Gills 3.3.2 Why Persist Anterior, or Pectoral Fins, While the Posterior Pair Is Reduced? 3.3.3 Segmentation of Body Wall 3.3.4 Why Is the Tail Preferred as Propulsive Organ? 3.3.5 Strength Variation of the Axial Skeleton in Aquatic Mammals 3.3.6 Diverging Locomotion and Body Shapes in Pinnipeds 3.3.7 How Do Amphibious Mammals (Pinnipeds, Otters, Beavers) Move on Land? 3.4 Do Alternative Technical Solutions Exist Among Aquatic Non-mammalian Vertebrates? Divergent Body Shapes and Locomotor Modes 3.5 Essential Results Chapter 4: Axial Skeleton and Muscle Arrangement in Terrestrial Tetrapods 4.1 Which Animals Are Called ``Tetrapods ́ ́ in the Present Context? 4.2 Why Is Trunk Morphology So ``Conservative ́ ́? 4.2.1 Physical Facts: Heavy Beam on Two Pairs of Supports 4.2.2 Body Stem in Primitive Tetrapods: Bending Moments, Shearing Forces 4.2.3 Structures to Resist Bending Moments and Shearing Forces: Axial Skeleton and Paraxial Muscles 4.2.4 Torsional Stresses 4.2.5 Structures which Resist Torsional Stresses: Oblique Muscles and Ribs 4.2.6 Sternum and Angulus Costae in Ventral View 4.3 Extremity Girdles Seen as Parts of the Trunk 4.4 The Earliest Known Example: Tiktaalik 4.5 Posterior/Caudal Cantilever: Tail 4.6 Anterior/Cranial Cantilever: Neck and Head 4.7 Morphological and Technical Alternatives: Turtles and Froglike Anurans (``Salientia ́ ́) 4.8 Essential Results Chapter 5: What Have the Extremities of ``Lower Tetrapods ́ ́ in Common? And Why? 5.1 Which Animals Are We Talking About? 5.2 Gravity and Ground Reaction Forces, Rolling Off and Segmented Extremities 5.3 Flippers Versus Segmented Limbs 5.4 Why Are Digits Directed Forward? Why at All Digits? Why Five Digits (or Less) and Not More? Why Hooves or Claws? 5.5 Consequences of Sprawling Limb Positions? 5.5.1 Zeugopodia and Abducted Stylopodia 5.5.2 Locomotion on Sprawling Limbs: Why Are There Horizontal Body Waves in Lower Tetrapods? 5.6 Why Are Elbows Turned Rearward, But Knees Forward? 5.7 Why Is There No Bony Connection Between the Shoulder Girdle and Trunk in All Terrestrial Animals? 5.8 Bipedality in Lizards and in Dinosaurs 5.9 Alternative Body Shapes and Locomotor Modes Among ``Lower Tetrapods ́ ́ 5.9.1 Salientia 5.9.2 Turtles 5.10 Essential Results Chapter 6: Birds 6.1 General Characteristics 6.2 Head, Why So Small? 6.3 Why Are Bird ́s Necks So Long? 6.4 Trunk, Why So Short and Compact? 6.5 Bipedal Locomotion on Ground. Gaits. Speed. Why Hopping or Running? Why the Characteristic Mass Distribution on Hindlimbs? 6.6 Why Are Three or Four Toes So Common? 6.7 Alternative Use Made of Hindlimbs. How and Why Do Hindfeet Differ Among Swimming and Diving Birds? 6.8 Frontlimbs and Flying 6.9 Alternative Use Made of Forelimbs Among Birds. What Do Flightless Birds with Their Wings? 6.10 Essential Results Chapter 7: Land-Living Mammals 7.1 General Characteristics 7.2 What Do ``Small Mammals ́ ́ Have in Common? 7.2.1 Autopodia, Claws 7.2.2 Parasagittal Limb Movements 7.2.3 Why Are the Limbs Moved in Parasagittal Planes Below the Trunk? 7.2.4 Are There Reasons for ``Small Mammal Locomotion ́ ́ on the Level of ``Biological Roles ́ ́? Strategy for Survival 7.2.5 Body Stem: Head, Neck, Trunk and Tail 7.3 Mechanics of Locomotion on Four Limbs. Gaits, Footfall Sequences 7.3.1 Striding: Speed, Ground Reaction Forces, Excursion Angles, Lengths of Limbs 7.3.2 Newly Invented Gait: Limb Pairs Moving in the Same Phase, Flexing and Extending the Trunk 7.3.3 Why Do Small Mammals Flex and Extend Their Body Axis in Bounding While Large Mammals Keep Their Trunks Unmoved? Does a B... 7.3.4 Why Are Hindlimbs Often Elongated? Jumping, Hopping and Bipedalism 7.4 What Are the Advantages or Disadvantages of Having a Long Tail? 7.4.1 Why do Kangaroos Hop and Not Run? 7.4.2 Alternative Shape and Locomotion: Hares and Relatives 7.4.3 Why Don ́t Hares Hop Bipedally, Like Kangaroos or Jerboas? 7.5 Large Cursorial Mammals 7.5.1 How Do ``Cursorial Mammals ́ ́ Look Like? Strategy of Survival 7.5.2 Are All Large Mammals ``Cursorial ́ ́? Does a Borderline Exist Between ``Small ́ ́ Mammals and ``Large ́ ́ Cursorials? 7.5.3 Free Limbs, Autopodia, Limb Proportions 7.5.4 How Do Cursorial Animals Move? 7.5.5 Modes of Locomotion, or Gaits, in Cursorial Mammals 7.5.6 Elastic Resilience of Structures and Spring Mechanisms Within the Limbs 7.5.7 Tracks: Support Patterns in Space 7.6 High Stressing Aside from Locomotion 7.7 Stress Patterns and Their Relation to Shape in Cursorial Mammals 7.7.1 Bending of the Body Stem 7.7.2 Shearing 7.7.3 Torsion 7.7.4 Shoulder Construction 7.7.5 Rib Cage and Individual Ribs 7.7.6 Pelvis 7.8 Neck 7.9 Special Load Cases Among ``Large Mammals ́ ́ 7.10 Essential Results Chapter 8: Primates: The Group Including Humans 8.1 What Are Primates? Which Characteristics Do (and Did) They Have in Common? 8.1.1 Eye Sockets in Tarsiers 8.2 How Dangerous Is Living in the Three Dimensions of Trees, High Above Ground? Frequency of Accidents/Injuries 8.3 How Are Prehensile Feet or Hands Used? Morphological Variation, and Which Forces Are Acting? 8.3.1 Qualities of the Transmitted Forces 8.3.2 Morphology of Dermatoglyphic Ridges, Pads and Nails 8.3.3 Any Connections Between Them? 8.4 Any Connections Between Friction, Dermatoglyphic Ridges, Pads, and Nails? 8.5 How Do Primates Move Around in Their Habitat? Modes of Locomotion, Gaits on Continuous Surfaces and the So-Called Climbing 8.5.1 Fast Gaits on Continuous Substrates 8.6 What About Moving in an Arboreal Habitat with Interrupted Supports? Particular Modes of Arboreal Locomotion 8.7 Bridging 8.8 Leaping 8.9 Suspensory Behaviour, Arm Swinging and ``Brachiation ́ ́ 8.10 Why These Characteristic Shapes of Skeletal Elements and No Others? Functional Morphology of Anatomical Details 8.11 Body Sizes of Primates, Facts and General Conditions 8.11.1 (How) Is Overall Body Size Limited in Primates? 8.11.2 Why are Some Primates Sexually Dimorphic? 8.12 Essential Results Chapter 9: Evolution of Hominids 9.1 What Do We Know About Early Humans and Prehumans? 9.2 Which Morphological Specialisations Have Been Developed in Homo Compared to Those of His Closest Relatives? How Do Fossil ... 9.3 Bipedal Locomotion and Its Influence on Body Shape 9.3.1 Why Are Human Hindlimbs So Long? Why Is the Human Trunk So Thin and Elongated? 9.3.2 Human Forelimbs and Twisting of Trunk 9.4 Human hands 9.4.1 Is There a Decisive Difference in Hand Morphology and Hand Use Between Humans and Other Hominoids? Problem of ``Precisio... 9.4.2 Are There Mechanical Reasons Which Favour Human Hand Proportions? In View of the Human Mode of Living? 9.5 Are Mechanically Based Conclusions Possible Regarding the Lifestyle of Prehumans? Beyond the Common Correlations on the Le... 9.5.1 Walking or Running? 9.5.2 Use made of the hands 9.6 Characteristics of the Hominoid Skull Shape 9.6.1 Morphology of Skulls 9.6.2 Brains 9.7 Are There Mechanical Reasons for Hominoid Head Shape? 9.8 Can Ultimate Reasons Be Pinned Down for ``Hominisation ́ ́ of Body Shape and Skull Configuration? 9.8.1 Acquisition of Bipedality 9.8.2 Why Have Humans Acquired Their ``Entaxonic ́ ́ Hand Proportions? 9.8.3 Skull Shape and Dentition 9.9 Essential Results Chapter 10: Open Questions 10.1 Is Shape Inherited or Ad Hoc Developed as a Response of Tissue to Stress? 10.2 Is Pauwel ́s (Wolff ́s) Law Also Valid in Invertebrates? The Case of Bivalves 10.3 Validity of Wolff ́s (Pauwel ́s) Law in Invertebrates: The Case of Sea Urchins 10.4 Homology of Tails 10.5 Further Research Required References Index "This book discusses how and why animals evolved into particular shapes. The book identifies the physical laws which decide over the evolutionary (selective) value of body shape and morphological characters. Comparing the mechanical necessities with morphological details, the author attempts to understand how evolution works, and which sorts of limitations are set by selection. The book explains morphological traits in more biomechanical detail without getting lost in physics, or in methods. Most emphasis is placed on the proximate question, namely the identification of the mechanical stresses which must be sustained by the respective body parts, when they move the body or its parts against resistance. In the first part of the book the focus is on primitive animals and later on the emphasis shifts to highly specialized mammals. Readers will learn more about living and fossil animals. A section of the book is dedicated to human evolution but not to produce another evolutionary tree, nor to refine a former one, but to contribute to answering the question: WHY early humans have developed their particular body shape."--Cover page 4