Written by Jon Mercer in Science
Viewed by 119 readers since 01-17-2009
Charles Darwin may never have seen the pink iguanas of Galapagos Islands during his many visits to study the evolution of finches; however, the rare species is offering scientists clues that may support his famous theory of evolution. The black-striped reptiles, unseen by humans until 1986, provide evidence of species divergence far earlier than Darwin’s famous finches.
According to a recent article on Reuters.com, scientists say that the rare species of iguanas adds to the understanding of evolution of species on the remote Galapagos Islands, which remain much the way they were millions of years ago. Many of the species found on the islands can be located no where else in the world. This is one of the things that inspired Darwin’s theory of evolution by natural selection.
Even after all the attention given to the Galapagos islands by Charles Darwin, they have yet to stop offering evolutionary evidence. The study of the pink iguanas not only offers evidence of ancient diversification along the Galapagos land iguana lineage, but also documents one of the oldest events of evolutionary divergence ever recorded.
A key element to the formulation of Darwin’s principles of evolution was his study of finch varieties with different shaped beaks scattered across the hundreds of archipelago’s islands when he visited there in 1835. In fact, at the heart of his studies on how one type of finch had evolved into several after a probable chance migration from Latin America thousands of years earlier, lies the basis for his famous book “On Origin Of Species”.
Darwin’s research showed that when the finches spread around the islands and their populations became isolated from each other, the birds adapted different shaped beaks that were more suitable to the type of berries they were able to harvest. Darwin never visited the area of the Galapagos Islands where the pink iguanas exist. If he had studied these creatures he may have discovered that their existence suggests that diversification in the Galapagos happened some five million years ago, much earlier than he originally attributed to the finches.
Genetic analysis of the pink iguana shows that the reptile originated in the Galapagos and split from other iguana populations some five million years ago when the archipelago island chains were still forming. These days, conservation efforts are underway to help preserve this rare species of iguana. Researchers have documented only forty of the reptiles in existence on a part of the Galapagos that is home to a 350,000 year old volcano.