The Biology of the Galapagos
The main biological features of Galapagos biodiversity are:
- Biogeographic Diversity - The Galapagos Islands are the only place on earth where species come from such a mixture of latitudes. Finding penguins on the equator looks like a biogeographic aberration or a joke of biogeography; but penguins are in fact there, swimming side by side with sea lions that came from the north and fur seals that came from south.
- Taxonomic Disharmony - Amphibians, a whole taxonomic class that includes frogs, salamanders and the like, are missing from the Galapagos. Upon closer examination, we find that many other taxa among both flora and fauna are missing entire groups that probably never reached or were unable to colonize the Galapagos. Thus, many of mainland South America's most prolific and widespread families and genus of birds, insects, and plants do not exist on the islands.
- High Endemism - Most groups of both terrestrial and marine biota display a splendid level of endemism that on average is about 50%. Some groups, such as the reptiles, reach almost 100%.
- Species Vulnerability Evolution in isolation has the advantage of producing unique forms, but at the same time carries the disadvantage--from a biological conservation point of view-- that most species have not evolved altogether mechanisms that will equip them to confront new competitors. For this reason, they also have difficulties avoiding new predators or diseases like those that are continuously being introduced by the human population. Restricted distribution-range and small population-size further expose them to any direct impacts of their natural habitat.