( Tropical areas of south and central Ame...)Why the Amazon rainforest is so rich in species

Tropical areas of south and central America such as the Amazon rainforest are home to some 7500 species of butterfly compared with only around 65 species in Britain. UCL scientists have ruled out the common theory that attributed this richness of wildlife to climate change, in a paper published on 7th December by the journal Proceedings of the Royal Society B (Biological Sciences).

Instead, scientists believe that biology played a far greater role in the evolution of species than external factors like prehistoric climate change. After conducting "DNA-clock" studies, which revealed that new species evolved at very variable rates, the scientists were able to conclude that external factors can only have had a limited impact on evolution.

This study's remit was not to put forward new theories, but Professor Jim Mallet, UCL Department of Biology, argues that his team's work shows that factors other than climate change play the greatest role in species evolution. He said: "Different types of rainforest butterflies in the Amazon basin are evolving at very different rates, not at all the pattern expected if forest refuges during the ice ages were causing the origin of new species ?the reason normally given. Instead, we think that idiosyncratic features of the biology of each species, such as competition for food and their individual reactions to the environment dictate the pattern of evolution in each group."

Professor Mallet and PhD student Alaine Whinnett tested the "DNA clock" using the mitochondrial DNA of nine different butterfly species groups [genera] on the eastern side of the Andes in Eastern Peru. By using a "DNA clock" the scientists were able to calculate the age of the species within each group of species. If the DNA is similar between any pair of species, they must have split recently. If the DNA has diverged a great deal between species, the species are probably ancient.

Some groups contain very young and rapidly evolving spec
'"/>

Source:University College London

Page: 1 2 3
Related biology news :

1. Amazon symposium to address large-scale conservation
2. Amazon source of 5-year-old river breath
3. Assessing the Amazon Rivers sensitivity to deforestation
4. Woods Hole Research Center plans controlled burn in Amazon rainforest
5. Ants, not evil spirits, create devils gardens in the Amazon rainforest, study finds
6. NASA satellite data provides rapid analysis of Amazon deforestation
7. Logging doubles threat to the Amazon, rivaling clear-cutting, study suggests
8. Amazon trees much older than assumed, raising questions on global climate impact of region
9. Satellites show Amazon parks, indigenous reserves stop forest clearing
10. Amazonian terra preta can transform poor soil into fertile
11. The Amazon in 2050: Implementing the law could save a million square kilometers of rainforest