Marine iguanas

Sun, 2011-07-17 14:56
Friday
15. July 2011
Darwin himself wrote: „The creature is ugly, of dirty-dark colour, stupid and plump in its movements”.

When he wrote these lines he did not had the Theory of Evolution formed out; he sketched out the first draft ten years later and published only a dozen years after that. Otherwise he would have found the marine iguana much more interesting – it is a living proof of the everlasting evolutionary processes of adaption and selection.

Originated from a land iguana washed ashore of these hostile, ill-equipped islands the only food source was underwater – the rich beds of algae and kelp. So the iguana had to go back into the water and changed – his tail became long and flat, flipper-like, he developed strong claws to hold to the rocks, and he even developed a way to drink the salt-water.

Before the island’s discovery by humans in the fifteenth century reptiles dominated many of the ecological niches normally inhabited by mammals. The human changed the sensible ecological balance by bringing domesticated animals, goats, cows, chicken, dogs, but also rats, mice and germs, by polluting the ecosystem and by extinguishing many of the endemic species. Natural evolution, a process of many generations, can’t develop new adaptations so quickly.

Human expansion in the last centuries seems to be one of the evolutionary mega-events, cause of mass-extinction like the meteor that ended the dinosaur age, and while we understand what’s happening we seem not to be able to change anything.

Location

Isla Floreana, Galapagos Islands
Ecuador
0° 47' 39.4296" S, 90° 51' 5.184" W