"We hope similar studies can shed light on the evolution of more species, including lizards, crocodiles and turtles".
Outbreaks of C. difficile, a bacterium resistant to many antibiotics, have been increasing in the United States since 2001, along with the evolution of more virulent strains.
Although neither of these frogs have any known predators, something clearly does prey on them: their high toxicity suggests that selection has driven the evolution of more toxic individuals.
Increased population densities of some species, for example, are likely to favour the evolution of more virulent genotypes of some parasites (see above The coevolutionary "arms race" versus reduced antagonism).
Canu saw all of this as an evolution of more traditional training — run, jump, lift, rest — something all the elite countries practiced in some form, only under different names.
More sophisticated techniques of ironworking, more extensive gold and copper mining, and a great increase in stone building suggest the evolution of more complex state structures, the growth of social inequalities, and the emergence of new religious and spiritual ideas.
And both further drove the evolution of more complex language.
"I would expect an evolution of more consumer- and enterprise-oriented smart phones," he says.
The researchers wondered if the evolution of more veins per leaf gave angiosperms the boost they needed to become widespread.
Human needs and desires have required a continued evolution of more and more sophisticated fluid-handling apparatus.
Once a given system of communication was well established, it constrained the evolution of more efficient communication systems.
