"Your Inner Fish," a new three-part series on PBS that premieres on April 9, explores evolution and the rise of human beings. In the first episode, the show will examine a little-known fossil tying human evolution to fish. 

Tetrapods are a group of animals possessing four main limbs, and including reptiles, amphibians and human beings. Biologists long suspected a common ancestor existed between tetrapods and fish. 

Neil Shubin of the University of Chicago led an expedition to Ellesmere Island in the Canadian Arctic to look for fossils in 1986. Among layers of sedimentary rock, Shubin found the remains of Tiktaalik, a species that could be the missing link between tetrapods and fish. 

Tiktaalik is a strange fossil, possessing qualities of both fish and amphibians. The ancient animals had flat, wide heads, shaped like a triangle. The body had features that are still found today among both fish and amphibians. A hind fin and pelvis of the species have recently been found. 

Shubin, a paleobiologist, wrote "Your Inner Fish," a book about his discovery. That title lends its name to the new PBS series. This was a new experience for the author, who found writing for television proved a challenge after writing a book. 

"It's a compromise. You have to keep it interesting, because the thumb is hovering just over the remote and about to change the channel to the sports game," Shubin told the press.

"Your Inner Fish" will explore the evolution of the species over 500 million years, using animated graphics. 

Human evolution will be at the center of the series, answering some of the most basic questions about human anatomy. Viewers will learn why we have five fingers, and walk on two feet, among other tidbits.  

"Our Inner Fish" was named best book of the year in 2008 by the National Academy of Sciences. 

Neil Shubin is new to a world of personalities explaining science to the masses, such as Neil de Grasse Tyson and Micho Kaku.

Shubin "made many other notable observations regarding the developmental biology of limbs, using his diverse fossil findings to devise hypotheses about the genetic and developmental processes that led to anatomical transformations. He is also committed to sharing the importance of science with the public, and his lab maintains an active presence on Facebook and Twitter," according to his biography on PBS.

"Cosmos: A Spacetime Odessey," hosted by Tyson and airing on Fox, has angered some viewers by exploring the evidence of evolution. Some critics also charge the program with treating religion unfairly. 

"Your Inner Fish" is nearly certain to attract many of the same criticisms as Tyson's show.