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Table of Contents

  1. THE INFINITE VARIETY: THE BEGINNING OF LIFE
    1. Darwin and the Giant Tortoises
    2. Evidence of Evolution in the Rocks
    3. Layers of Rocks give us clues to their age
    4. How life started?
    5. Interpretation of the Miller-Urey Experiment
    6. How valid was the Miller Urey Experiment?
    7. DNA the blueprint for life
    8. Oxygenating the World
    9. Protista - basic unicellular organisms
    10. Protista Diversity
    11. The first Multicellular Organisms?
    12. Ctenophores and Cnidarians - first organism with real structure
    13. Cnidarians and the Fossil Record
    14. Coral Reefs under threat
    15. Test Yourself
    16. Assignments
  2. BUILDING BODIES: INVERTEBRATES OF THE OCEANS
    1. Fossil History of Marine Invertebrates
    2. Platyhelminthes: the building block for other invertebrates
    3. Platyhelminthes: a surprisingly diverse group
    4. Annelids: the first segmented animals
    5. Brachiopods: developing a bivalve shell
    6. The first Molluscs
    7. The Molluscs diversified
    8. Molluscs: Feeding mechanisms
    9. Molluscs: Evolving and keeping the shell
    10. Molluscs: Secondary loss of the shell
    11. Echinoderms: Penta-symmetrical creatures of the oceans
    12. Echinoderms: A hydrostatic structure
    13. Echinoderms diversity: variations on a theme
    14. Arthropoda: the most successful animal phylum
    15. Arthropoda: Segmentation the successful formula
    16. Early Arthropods: The fossil record
    17. Living descendents of the Trilobites
    18. Crustaceans: Arthropod success in the sea
    19. Arthropod Exoskeleton: Evolving to occupy land
    20. Test Yourself
    21. Assignments
  3. THE FIRST FORESTS
    1. Plants: Fertilization and dispersal, the first issues
    2. Mosses: Possibly the earliest land plants?
    3. Fossils of the earliest land plants
    4. What were the earliest land animals?
    5. Living of Land: Issues of reproduction
    6. Land plants: Making their mark
    7. A Forest Environment
    8. Insects: The greatest conquerors of all?
    9. Land Plants: Still working on the reproduction issue
    10. Cycads: Getting to grips with the reproduction on land
    11. Conifers: A successful formula
    12. Earliest plant defences against herbivores
    13. Plants and Insects find "mutual benefit"
    14. Beetle pollination
    15. Plants learn to manipulate
    16. The most bizarre pollination systems?
    17. Total dependence: Yuccas and Moths
    18. Test Yourself
    19. Assignments
  4. THE SWARMING HORDES
    1. A Tripartite body plan
    2. Chitin: A secrete ingredient for success?
    3. Issues with an Exoskeleton
    4. A "Larval Stage" leads to success
    5. Larva: Clothed in silk
    6. Metamorphosis
    7. An insect's first flying lessons
    8. Insects: Finding your soul mate
    9. An Insect's approach to rearing your young
    10. Insects: Limitations for size
    11. Insect's approach to size matters
    12. Chemical Communication
    13. Establishing a new colony
    14. The termite towers
    15. Wasp and Bee nests
    16. Dance of the bees
    17. Insect and plant cohabit
    18. Imperialism- Insect style
    19. Test Yourself
    20. Assignments
  5. THE CONQUEST OF THE WATER AND THE BIRTH OF THE VERTEBRATES
    1. Free-living chordates
    2. Fossil evidence for the first chordates
    3. A jawless predator
    4. Ostracoderms - an extinct group with heavy armour
    5. Protofish and internal bony skeletons
    6. Developing some backbone
    7. Re-inventing the cartilage skeleton
    8. Sharks and Mantas
    9. Swimbladders: refinement
    10. Test yourself
    11. Assignments
  6. THE INVASION OF THE LAND
    1. The conception of lungs
    2. Possible ancestors
    3. Amphibians: The limitations
    4. A variety of habitats
    5. Colonizing the land
    6. A burrowing existence
    7. The accomplished jumpers
    8. The sticky tongue
    9. Sound production
    10. Amphibians: Mating
    11. A terrestrial environment for breeding
    12. Protecting the young
    13. Marsupial frogs
    14. Parental care: A step further
    15. Brooding in the stomach
    16. Effects of climatic conditions
    17. Moisture and development
    18. The water-holding frog
    19. Test Yourself
    20. Assignments
  7. A WATER-TIGHT SKIN AND THE SHELLED EGG
    1. Issues: Ectothermy vs Endothermy
    2. Breeding mechanisms of the ancestral reptile
    3. Skull structure
    4. The Anapsids
    5. The Diapsids
    6. The Synapsids
    7. First dinosaur characteristics
    8. Dinosaur fossils
    9. Gigantic herbivores and carnivores
    10. Temperature regulation limits energy use
    11. The beginning of the end for the kings
    12. Impressive parental care
    13. Conquering various living environments
    14. The flight of the dinosaur
    15. The Pterosaur: The take-off
    16. The Ptesosaurs: Not just a gliding motion
    17. The extinction
    18. Mammals' role in extinction
    19. Change in climate
    20. Crocodiles
    21. Crocodiles: Social life
    22. The Order Chelonia: Modified
    23. The lizard
    24. Modifying the scales
    25. Limb reduction
    26. Snakes
    27. Snakes: Making waves
    28. Snakes: The predator
    29. Snakes: Nurturing the young
    30. Snakes: The nocturnal hunter
    31. Test Yourself
    32. Assignments
  8. LORDS OF THE AIR
    1. Claws for climbing
    2. Tree-perching birds
    3. Fossils of bird-like dinosaurs
    4. Weight reduction by birds
    5. The basic bird plan of structure
    6. Bill structure: Evolving
    7. Feathers: Differentiation and adaptation
    8. The structure of feathers
    9. Feather coloration: Melanins and carotenoids
    10. Feather Differentiation of plumage
    11. Feathers: Specialized
    12. The Birds of Paradise
    13. Courtship: Behavioural patterns
    14. Birds: Copulation
    15. Incubating the eggs
    16. Protecting the eggs
    17. Precocial and altricial chicks
    18. The relationship between the anatomy and flying
    19. Flight: Speed and distance
    20. Migration: A semi-annual event
    21. Losing flight
    22. Test Yourself
    23. Assignments
  9. EGGS, POUCHES AND PLACENTAS
    1. The Spiny Echidna
    2. The loss of teeth
    3. Absorbing heat
    4. An endothermic metabolism
    5. Mammals: A polyphyletic origin
    6. The earliest true mammal
    7. The Opossums: The pouch
    8. Caring for the young
    9. Marsupial fossils
    10. Carnivorous marsupials
    11. The splitting world
    12. Evidence supporting continental drifting
    13. An alternative method of nourishing the young
    14. Placental mammals vs Marsupials
    15. Marsupials: Opportunity to evolve
    16. Survival today
    17. Marsupials and placental mammals: A resemblance
    18. Major differences
    19. The rat kangaroo
    20. Kangaroo: Escaping predators
    21. Kangaroo: The teeth
    22. Kangaroo: Reproduction
    23. The effect of drought on reproduction
    24. The placental mammals dominate
    25. The placenta
    26. The mammalian sexual cycle
    27. Immunological rejection
    28. Placental mammals: Success
    29. Test Yourself
    30. Assignments
  10. THEME AND VARIATION
    1. Dinosaur domination
    2. Various insect-eating mammals
    3. Shrews: Characteristics
    4. The Mole: Going underground
    5. Mole tunnels as traps
    6. Insectivores: A sticky tongue
    7. The pongolins
    8. Pongolins: Protection
    9. The armadillos: Characteristics
    10. Various species of armadillo
    11. Specialist ant-eaters: Lack of teeth
    12. Taking to the skies
    13. The Colugo: Gliding
    14. Bats: Flapping flight
    15. Bats: Saving weight
    16. Bats: Echo location
    17. Bats: Sonar equipment
    18. Methods for avoiding predation by bats
    19. Bats: Diet
    20. Meat-eating and fish-eating bats
    21. The vampire bats
    22. The Yellow-eared Bat
    23. Cetacean fossils
    24. Whales: An aquatic existence
    25. Whales: Adapting to swimming life
    26. The diet of whales and the sounds of dolphins
    27. Dolphins: A language
    28. Whales: A song
    29. Evolving communities
    30. Test Yourself
    31. Assignments
  11. THE HUNTERS AND THE HUNTED
    1. Plant eaters: The teeth and digestion
    2. Elephants: Aiding digestion
    3. Compensation by plants
    4. Ruminants
    5. Animals prepare for food shortage
    6. The hibernating dormouse
    7. Flying squirrels
    8. Monkeys: Coordination development
    9. The Sloth: Characteristics
    10. The Sloth: Mating and predators
    11. The forest floor: Vegetation
    12. The large herbivore
    13. A solitary life
    14. Specialized meat-eaters
    15. Grass: Highly advanced
    16. The spread of the grassland
    17. Smaller is better
    18. Mole rats: Safety in the burrows
    19. Mole rats: Teamwork
    20. Prairie dogs: Organized social systems
    21. Prairie dogs: Selective cultivation
    22. The viscacha
    23. Placental migration
    24. Proto-horses: Lengthening the legs
    25. Proto-horses: The teeth and skull
    26. Descendants of the forest dwelling antelopes
    27. Antelope: Safety in herds
    28. Breeding arrangements
    29. The improved predator
    30. Lions: Hunting
    31. Hyenas: Communication and hunting
    32. Hyenas go zebra hunting
    33. Test Yourself
    34. Assignments
  12. A LIFE IN THE TREES
    1. An ancestor to the primates
    2. The Ring-tailed lemur
    3. The male Ring-tailed lemur: The use of scent
    4. The Ring-tail: Time in trees
    5. Infant lemurs
    6. Sifakas
    7. The Indris
    8. The nocturnal lemurs
    9. The Aye-aye
    10. Competing with monkeys
    11. The Loris: Sign posting
    12. The Tarsier
    13. Monkeys: Sight is key
    14. Monkeys: The use of colourful displays and sound
    15. Monkeys: Anatomical features
    16. Scent in communication
    17. Marmosets
    18. Adapting to great weight
    19. Prehensile tails
    20. The adaptable Macaque monkey
    21. Macaques: Behavioural patterns
    22. Bi-pedalism
    23. The Orang Utan
    24. The Orang Utan: Supporting the great weight
    25. The Orang Utan: It's repertoire
    26. The Orang Utan: Solitude and size
    27. The Gibbons
    28. Gibbons: Family life
    29. Gorillas: The use of the arms
    30. Gorillas: Family groups
    31. Similarities between Gorillas and humans
    32. Gorillas: A placid existence
    33. Chimpanzees: Their diet
    34. Chimpanzees: Maternal support
    35. Chimpanzees: A friendly gesture
    36. Chimpanzees: The toolmakers
    37. New situations lead to greater change
    38. Test yourself
    39. Assignments
  13. THE COMPULSIVE COMMUNICATORS
    1. Characteristics of plains-living apes
    2. Development of ape men
    3. Homo erectus: Adaptation
    4. Homo erectus: Toolmaker and hunter
    5. Homo erectus: Methods of communication
    6. Recognizing one another
    7. Gestures: Providing information
    8. Homo erectus: Increase and spread
    9. A changing climate
    10. Homo sapiens
    11. Culture and cultural identities
    12. Test Yourself
    13. Assignments

Kangaroo: The teeth

The second difficulty that grass eaters must overcome is the wear and tear on their teeth. Grass is tough, due to the silicates that occur in them, and breaking it down into a pulp in the mouth is very abrasive on the teeth. Grazers elsewhere have molars with open roots so that wear can be compensated by continuous growth throughout the animal's life. In kangaroos the roots of the teeth are closed, and they have evolved a different system of tooth replacement. There are four pairs of cheek teeth on either side of the jaws. Only the front ones engage. As they are worn down to the roots, they fall out and those from the rear migrate forward to take their place. By the time the animal is fifteen or twenty years old, its last molars are in use.

Kangaroo Dental Structure