Evidence of Evolution

Introduction

It is believed the marine iguanas (bottom photo) diverged from their ancestors, land iguanas (top photo), 5.7 million years ago. Theories abound that land iguanas were possibly drifted to the islands on driftwoods or debris, and as time went on these iguanas learned to adapt and evolve within their new enviroment. Traits such as swimming to hunt, "sneezing out" excess salt because of swimming, blunt snouts to feed on algae, were all developed through natural selection in order to survive on the islands. 

Comparative Anatomy

First, let's use comparative anatomy has a sign of evolution. Marine iguanas descended from land iguanas and evolved accustomed to the ocean. The land iguana has short claws, while marine iguana's have longer claws to grip on the sea floor to help with the tides. Marine iguana have flat faces help them consume algae. Land iguanas have a more pointed nose that helps them eat cactis without getting hurt. These different phenotypes show the difference in there habitats have made adjustments.

Comparative Embryology

We can compare the embryos of a close relative or species of the marine iguana. Birds surprisingly are close relative to the iguana's in general. iguana develope longer tails and thinner body shape, whole chicken embryo develope 'wings' and a beak. Both have enlarged eyes.  This may show over time iguana's developed blunt nose rather than a beak like the chicken to help in their enviroment. The change maybe the result of continental drift making changes in their habitat leading to drastic phenotypes between the two different animals.

   

(Drawing due to lack of embryo pictures)

No fossil, vestigial or molecular biology evidence found.