Of midgets and giants

I didn't know that in island environments small mammals (e.g. rodents) tend to evolve to be larger (Island gigantism), and large mammals (e.g. elephants) tend to evolve to be smaller (Island dwarfism). This is not considered to be evolutionary trend by some due to the fact that different parameters apply in an isolated island environment. Wikipedia telle me that J. Bristol Foster published his work in 1964, now known as 'Island rule', in which he suggested the simple explanation that smaller creatures get larger in the absence of the predators they had attracted on the mainland and larger creatures become smaller with the absence of food sources. An article in Science Daily suggests, however, that the original size of the species was said to be the key determining factor in these changes. And that the new research by a group in Imperial College London have shown that "bigger becoming smaller and vice versa" is not always the case and varies depending on each islan's environment.

Interestingly, recent research in marine biology led by MBARI postdoctoral fellow Craig McClain suggests that a similar trend affects animals as they adapt to life in the deep sea. However, once again the trends are not uniform from species to species and the causes are not very clear either. So in general, it looks like we've still got quite a bit to learn about our fellow Earthlings in isolated environments.