Tiny Crawlers Walked the Land 460 Million Years Ago
The News
Scientists at Virginia Tech just finished building the first complete family tree of every kind of millipede alive today. Using DNA from 82 species and 29 fossils, they figured out that millipedes were crawling around on land about 460 million years ago — that's 80 million years before any animal with a backbone took its first step out of the water.
Professor Pip pushed aside a curtain of ferns and dropped to his knees on the damp forest floor. "Aha! Right where I left it." He pulled out his big round magnifying glass and pointed.
Curled in the leaf litter was a tiny creature with dozens of little legs, no longer than Pip's thumb.
"Friends," said Pip, his spectacles slipping down his nose, "say hello to a millipede. And then say a much, much bigger hello — because their family is older than just about anything walking on this planet."
"Older than dinosaurs?" asked Leo, mouth dropping open.
"OH my whiskers, yes." Pip's tail swished. "Older than dinosaurs. Older than frogs. Older than any animal with a backbone that crawled out of the water. Scientists in Virginia just finished the most enormous millipede family puzzle ever made, and the answer is — millipedes were tromping around 460 million years ago."
"460 MILLION?" Mia gasped.
"Let me show you what that means." Pip pulled a brown leaf from his pocket. "Pretend this leaf is dead. Pretend it just fell." He set it on a smooth rock. "Now picture our millipede friend. What's their job?"
"Eat it?" Leo guessed.
"PRECISELY!" Pip clapped. "Munch, munch, munch. Tiny pieces. Then teeny crumbs. Then — and this is the wonderful part — the crumbs become dirt. Good rich dirt that other plants can grow from."
He winked. "That's called being a detritivore. A grown-up word that means: someone who eats dead stuff to recycle it. Millipedes are the world's oldest recyclers. Scientists call them ecosystem engineers — little workers building healthy soil for everyone else."
"Like the soil for OUR garden!" said Mia.
"For every garden, ever, anywhere," Pip nodded. "And here's the most amazing part. Back then — 460 million years ago — there were no trees yet. No leaves. No flowers. Millipedes ate decaying mosses and ancient muck. They were the very first land cleaners."
He looked up at the trees swaying above. "Every forest you've ever seen started with creatures like this one quietly recycling the world."
"What do they recycle if there's no leaves to eat?" Leo asked.
"They eat whatever bits of life have finished living," Pip said softly. "Today, that's leaves. Back then, slime and moss. The job is the same."
He carefully set the millipede back under a fern. "Tonight, when you take a bite of a vegetable from anyone's garden, give a little thank-you to the millipedes. The soil it grew in had help from a family 460 million years old."
Spark a Conversation
- If millipedes have been around for 460 million years, what does that tell us about what makes a good "job" in nature?
- What would happen to forests if there were no millipedes, beetles, worms, or other recyclers?
- Can you think of any "recyclers" in your house — animals or even tools — that turn old stuff into new stuff?