Meet your most recently discovered ancestor:
Image Credit: Nature, Conway Morris, Jean-Bernard Caron, Marianne Collins
She may not look like much, but this little critter likely helped take us from spineless sea creature to walking, crawling (running, jumping) human some 500 million years ago.
That's because she was one of the first animals to have a backbone.
Well, sort of.
Metaspriggina, as our ocean-dwelling ancestor is known, had no hard bones in its skeleton. But a tough rod of cartilage — the hard tissue still found in the discs between the vertebrae in our spine — extended from its head to its tail, stabilizing its body. Human embryos have the same rod, called a notochord. As we grow, it morphs into the cartilage in our spine.
The animal also appeared to have eyes with lenses, meaning it could see complex images, and a nose. But while many animals use these tools to find their next prey, scientists say Metaspriggina was likely more interested in trying to avoid becoming a predator's meal. Because its eyes are mounted at the top of its head, researchers suspect it kept watch on potential predators swimming above. The animal also had the muscles to power a quick escape: Scientists found W-shaped bands of muscle along the length of its body, the same type that modern-day fish contract to thrust themselves forward.
The researchers published their findings in the journal Nature. They unearthed the latest Metaspriggina remains in the Burgess Shale, a massive fossil field in the Canadian Rockies. Here, other scientists have uncovered the most concentrated remains of our earliest mineralized — and hence readily fossilized — ancestors.
Image Credit: Flickr
One of the study authors, Royal Ontario Museum paleontologist Jean-Bernard Caron, came across his first Metaspriggina remains in 2012. Another expert on the subject, the University of Cambridge's Simon Conway Morris, reported seeing the same creature's fossils back in the 1970s and published a study on them in 2008. But it was not until the two paired up that they discovered the significance of the remains. After days of carefully chipping away at some of Caron's newly discovered specimens, the researchers uncovered a complete Metaspriggina fossil.
The detailed discovery gives us a never-before seen peek at some of our earliest ancestors. It also helps us understand how our own bodies came to be.
This is critical, considering that a Gallup report issued this year found that 42% of Americans believe that "God created humans in their present form 10,000 years ago." Even among people who said they were "very familiar" with the theory of evolution, a third still said God made us as we are today.
Denying the central organizing principle of modern biology is trending: In 2012, Sen. Marco Rubio (R-Fla.) told GQ that "Whether the Earth was created in 7 days, or 7 actual eras, I’m not sure we’ll ever be able to answer that." Republican Michele Bachmann told a debate audience in St. Cloud, Minn., that "There is a controversy among scientists about whether evolution is a fact.”
This is surprising, since the National Academy of Sciences — the group that Congress empowers to champion science in America — issued a report in 2008 that concluded that creationism, a "nonscientific approach to learning" did not belong in the classroom.
It seems people need some reminding. Perhaps Metaspriginna can do the job.