Showing posts with label tropics. Show all posts
Showing posts with label tropics. Show all posts

Pheidole Ants Rule the World

Man is not the only animal to dominate the Earth. Pheidole ants have spread over all the livable continents. They are so common that a walk in a tropical forest means some are killed by just stepping forward.

There are 1,200 species of the genus Pheidole. Each has developed to exist in a particular niche of the ecosystem. In a study of 300 species it has been found that certain species evolved similar characteristics independently.

Species proliferated dramatically - from one to 600 species in the Americas. The evolutionary goal was to dominate all niches, first in the New World then in the Old. Expansion across one was independent of the other. Evolution took its own course.

Ants are essential for healthy ecosystems. They aerate the soil, disperse seeds and help move nutrients. In biomass they equate with all vertebrates. Their study is indeed important
Biology by Ty Buchanan
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Cat Colored Spew

"I know I shouldn't have eaten that."
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Funny Animal Photos
-------Australian Blog-------

Evolution is Faster in the Tropics

It seems that with climate change we will lose some species but gain new ones - or have new "changed" species. Some species living at high altitudes have been changing as mountain tops become warmer with climate change. It was believed that accelerated evolution only occurs in cold regions, but it has been discovered that it also happens in the tropics.

While it has been accepted for a long time that plants and marine protists evolve faster, the process has only recently been recognized in mammals. What is unusual is that mammals are not directly affected by a warming climate because they naturally maintain a steady body heat.

It is now believed that evolution in the tropics is even faster that in temperate regions. There is a greater diversity of species in the tropics. This faster evolution and more species means that adaptation to changing conditions is rapid. The faster evolution actually makes for many more types of animals.

There must be something else, however, that is driving change in mammals than just a warming climate. Genes were studied from closely related mammals at both high and low altitudes. It was found that DNA substitution was much faster at low, warm latitudes. There are two theories on why this is happening: 1) mammals act in sympathy with other animals; and 2) mammals slow down and become torpid in a colder climate.

Personally, neither of these two theories seem realistic. Why should mammals act in Sympathy? Moreover, mammals in cold climates actually appear to be more active.
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