KOALAS AND EUCALYPTUS TREES

The size of brain of the koala tells an almost unbelievable story
about evolutionary problems.
In the eucalypt forest, koalas and their young cubs search for the
tender new eucalypt leaves that make up their whole diet. Koalas
eat nothing else. But eucalypt leaves are full of dangerous
chemicals and are very low in nutrients.
Therefore koalas have evolved to be one of the greatest energy
misers on this planet. They conserve the little energy that they get
from their diet of leaves. Their movements are very slow and they
have a very low rate of reproduction.
But there is one more strange thing. Marsupials are known to have
very small brains. In the case of the koala, it is the only mammal
on earth whose brain does not fill up the cavity of its skull. Forty
percent of the space of the skull is just fluid.
Brains use up more energy than any other part of the body. A
Koala brain large enough to fill the skull would use too much
energy, energy that a koala cannot get from the diet.
Therefore it may be said that the koala has traded brain power for
survival. It is better to survive with a tiny brain, that not to survive
at all.
Edited versions of an ABC Radio Report by CJ

Tree smashes into car

Perth Nov. 28th 2012

A Eucalyptus tree crashes onto a car during a severe storm with wind- speeds up to 100 km/h.

教え：Never park your car under a tree during strong wind storms.

高さ70mを超える熱帯雨林種のユーカリ@オーストラリア

現地スタッフより、ABC放送でユーカリの話題があったということでご紹介します。


Giant Eucalypts are a Rainforest Species.
ABC 放送　　　　　　　　　　　　　　　　　 　Rachel Sullivan 1 Nov 2012
The giant fire-dependent eucalypts trees should be classified as rainforest species.
Of the world's 46 living giant tree species - those exceeding 70 metres in height - most are
either Conifers found along the Pacific North West Coast of North America or the
Eucalypts from Southern and Eastern Australia.
"Australia is an epicentre of giant trees, of these, the tallest is Eucalyptus regnans growing
in Eastern Victoria and Tasmania, they can reach 100 m in height. They are the largest
flowering plant on the planet. The conifers of North America may be a little taller, but
they do not produce flowers.
The researchers at the University of Tasmania looked at the ecological and phylogenetic
distributions of giant trees, the characteristics eucalypts share with other giants, their
relationship with fire and the unique ecological relationship eucalypts have with rain forest.
"Giant eucalypts have been a puzzle because they require fire to regenerate, yet tower
over the rainforest tree canopy that regenerates without fire," says Professor Bowman.
"They are incredibly competitive when they are young, yet once established, co-exist
happily with invading rainforest species. Their evolutionary advantages allow them to
outcompete other species, however they occur on the margins of rainforests. They are
remarkably long-lived, they can live for up to 500 years.”
"Giant trees have huge value for the timber industry, yet there are strong environmental
reasons for their protection. "Classification as rainforest trees, albeit those with a unique
dependence on fire, adds support to arguments in favour of old growth conservation."