Inner Fish

The book, Your Inner Fish, is an introduction to Biology! Your Inner Fish is mainly about how Dr. Shubin found an organism, Tiktaalik that, for all intents and purposes, is the perfect transitional organism between fish and amphibians.

Dr. Shubin propsed a hypothesis in the book: If all vertebrate land animals descended from a common ancestor that had that limb structure, then we should be able to find that common ancestor in rock of an appropriate age. Based on this general thought, Dr. Shubin then started searching for this partiular transitional oraganism's fossil. Hard work eventually paid off. After years of hardworking, Dr. Shubin finally found this special fish that lived in 375 millions years ago, Tiktaalik.

Why is Tiktaalik so special? It's just a fish, isn't it? NO! Tiktaalik has features both of fish and amphibians. Though Tiktaalik has fins and scales, it has a flat head that is different from other fish. Also, Tiktaalik's eyes are on the top of his flat head, not on the side. The special location of its eyes provides a better view for him on land.  The most fascinating part is that Tiktaalik has short forearms. Forearms enable Tiktaalik to do push - ups so that it can survive and hunt better on land. Furthermore, Tiktaalik is a great example for studying homology. Based on the structure of Tiktaalik, paleontologists could figure out the similarities between organisms and find out more information about evolution.

*Evidence for evolution: Fossil / homology / geology

Dr. Shubin and Tiktaalik

The amazing missing link! --- Tikataalik