Wave header image graphic banner
Public Radio For Eastern North Carolina 89.3 WTEB New Bern 88.5 WZNB New Bern 91.5 WBJD Atlantic Beach 90.3 WKNS Kinston 88.1 W201AO Greenville 88.5 WHYC Swan Quarter
Play Live Radio
Next Up:
0:00
0:00
Available On Air Stations

Fossil shows fish evolved to walk on land — then went back to the water

MARY LOUISE KELLY, HOST:

You may have come across a meme showing an ancient fish known as a Tiktaalik. It shows illustrations of a green, eel-like, ancient fish.

JUANA SUMMERS, HOST:

Scientists say, around 375 million years ago, that fish crawled from the sea with the physical characteristics to survive on land.

KELLY: A notable link in the evolutionary chain - and versions of the meme basically urge the fish to crawl back into the water to avoid the woes of our modern times.

SUMMERS: But there's new evidence that maybe a version of it did turn right around.

NEIL SHUBIN: It's basically - you had this evolutionary series of fish evolving to walk, but this one said, eh, not going to do that one. I'm going back in.

SUMMERS: That is professor Neil Shubin. He's a paleontologist at the University of Chicago. He first discovered a fossil of Tiktaalik in the Canadian Arctic in 2004, and now he's co-authored a new study on the recent discovery of another related species.

SHUBIN: This new species is a very close cousin of Tiktaalik. We know that by looking at all the features. In fact, it's a very close cousin of both Tiktaalik and creatures with arms and legs and fingers and toes, so-called tetrapods.

KELLY: They call this cousin a Qikiqtania wakei. Using different statistical models, the team was able to conclude that these two fish were related.

SUMMERS: Thomas Stewart is an evolutionary biologist and associate professor at Penn State who also worked on this study. He says the newly discovered fossil has a totally different fin from its relative.

THOMAS STEWART: This animal, despite being closely related to a lot of other animals that are propping themselves up on the ground - whether underwater or perhaps on land - this is an animal that was using its fins for swimming.

SUMMERS: So while one had fins with bones more similar to a human and venturing out onto land, the other was going back to the water, likely because it found advantages for survival in the water again. Qikiqtania is a clear example of just how complicated evolution can be. Professor Thomas Stewart again.

STEWART: We got introduced to the idea of evolution through images like an ape that slowly stands upright and then produces a man walking. Those are some of these classic, iconic teaching tools that people have used to introduce the idea of evolution.

KELLY: But Stewart and Shubin both say this new discovery is an example of how evolution doesn't quite work in a linear way.

SHUBIN: Evolution is much more of a bush - a tree of creatures evolving in many different directions.

SUMMERS: We'll see how the memes evolve from here.

(SOUNDBITE OF MIRAA MAY SONG, "INTERNET TROLLS") Transcript provided by NPR, Copyright NPR.

Kai McNamee
Ashley Brown is a senior editor for All Things Considered.