BCB705 Biodiversity: Chapter2 - Evolution of Biodiversity

Table of Contents

1. THE INFINITE VARIETY: THE BEGINNING OF LIFE
2. BUILDING BODIES: INVERTEBRATES OF THE OCEANS
3. THE FIRST FORESTS
4. THE SWARMING HORDES
5. THE CONQUEST OF THE WATER AND THE BIRTH OF THE VERTEBRATES
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
8. LORDS OF THE AIR
9. EGGS, POUCHES AND PLACENTAS
10. THEME AND VARIATION
11. THE HUNTERS AND THE HUNTED
12. A LIFE IN THE TREES
13. THE COMPULSIVE COMMUNICATORS

The water-holding frog

The zenith of amphibian's adaptations to minimize their dependence on water under arid conditions is the water-holding frog, Cyclorana which inhabits the central desert regions of Australia. During the brief and infrequent periods of rain these frogs feed on the flush of insects, they mate and lay their eggs in tepid shallow pools of water, the eggs hatch and tadpoles rapidly develop into froglets. As the rain soaks away the frogs and froglets absorb as much water as possible and bury themselves deep into the sand where they secrete a membrane around themselves to prevent moisture loss. They remain in this condition until the first significant rains, which could be in several years time.

Water-holding frog Cyclorana platycephala