On the other side of the world, in the jungles along the Orinoco river, a group of hoatzins feeds among the treetops.
Like so many other species, the hoatzins came about as a response to the opportunity of feeding and living permanently in the tops of the trees of the Amazon. And as their ancestors had sufficient time – a period which geologically is not very much, but which is measured in millions of years – the result was this species, a bird vitally linked to the trees on which it feeds; a specialisation that enables the hoatzins to feed without having to make long flights.
For the carnivores, however, things are not as easy, and they have to hunt down their prey.
The birds of prey armed themselves with claws and beaks capable of killing. In the same way as the large carnivorous dinosaurs, which we now know also had feathers, the hunters of the air needed to develop resistance, speed and skill in flight; just the opposite of the peaceful hoatzins.
Wherever life had time, the species adapted to all types of conditions. And they still continue to do so.
It is a surprising case, but which demonstrates the adaptability of the species, animals that are the result of thousands of evolutionary experiments in harsh competition against other animals. Before the present day seagulls, capable of eating almost anything and colonising any ecosystem from pole to pole, there have been dozens of different ancestors who gradually refined the most efficient features to survive in increasingly difficult conditions. It is the opposite solution to that of the super-specialists, animals that are very well adapted to a specific environment but which completely depend on it.
Since the origins of life, organisms have become increasingly complex.
The new species, the new prototypes of life, are more effective, more sophisticated and precise.
Since life began to devour itself, that is, since the appearance of the first beings capable of feeding on other living organisms, our planet has become a world of hunters and prey.
Increasingly sophisticated weapons were perfected for aggression and flight, to prowl and to hide, to capture the prey and flee from the hunter.
It didn’t matter where these new adaptations ventured in order to colonise new ecosystems. Wherever there was potential prey, in time a hunter would appear.
And killing in order to survive became the general rule, an inescapable law to which we are all subject, be it as killers or as victims.
The seals and the sea lions exploit the unlimited resources of the oceans, feeding on fish and marine invertebrates. But other mammals went further and became seal hunters.
These new hunters had a well developed social structure, a weapon that enabled them to hunt in groups.
Large predators of the sea, like the sharks, were forced to give up their position in the food pyramid.
These organised groups turned the rest of the marine creatures into potential prey, and not even the enormous blue whales were able to escape the threat.
Today, there is no other animal in the oceans that can compete with a family of killer whales. The power of the individual is reinforced by the power of the group. Shared work and risks with shared rewards.
he killer whales are an example of the power of evolution and a demonstration of its axioms. If there are no sudden changes of global magnitude, the new species obey the theory of natural selection. And the best adapted survive.
