Friday, June 12, 2015

Chasing Kangaroos by Tim Flannery ***

Chasing Kangaroos by Tim Flannery traces the history of Australia and the kangaroos from the beginning through the author's career as an archeologist, evolutionary biologist, and ecologist. This task is hindered by massive holes in the Australian archeological record. Mammalian remains and fossils only exist for five periods:
  • Age of dinosaurs: 115-100 million years ago
  • The Murgon age: 65-54 million years ago - first marsupials arrive from South America
  • Age of koala beasts: 40-20 million years ago
  • Age of diprotodontids: 20-5 million years ago
  • Age of kangaroos: 5 million years ago to present
In the last 100 million year, approximately half the fossil record is missing. This prevents a complete story from being told, but there is lots of interesting information in the remaining 50 millions years.

For example, one of the problems paleontologists have is pyrites disease:
Iron pyrites form in specimens preserved in oxygen-less environments, and whehn such fossils come into contact with humid air the pyrites turn into sulfuric acid, causing bones to decay to grey, puffy dust.
Though Australian archeologists suffer from missing years in their fossil record, they proudly have the oldest rocks on the planet - 4.2 billion year-old zircons.

Prior to the arrivals of Europeans the Aborigines and the kangaroos were both ideally adapted to the arid climate and both thrived. With the introduction of European technology and agricultural practices, both seem to be on the inexorable road to extinction.

Flannery explores the exact reasons at length. It could be introduced species, climate change, lack of fires, additional watering holes, removal of predators (dingos), etc. At this point the research is inconclusive.

While the topic of how different species adapt to the arid Australian environment is fascinating, the book seems more like a collection of articles than a consistent narrative, and at many points the technical vocabulary was overwhelming (as with age of diprotodontids above).

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