Summary
Scientists from MIT suggest that the first animals on Earth might have been sea sponges, based on a study of ancient rocks. They found chemical fossils, specifically steranes, from more than 541 million years ago, which link back to sponges. This study builds on earlier work that began in 2009.
Key Facts
- MIT researchers believe sea sponges were among the first animals based on chemical fossils.
- These fossils were found in rocks over 541 million years old from the Ediacaran Period.
- The study focused on special molecules called steranes, which are stable forms of sterols.
- Steranes were linked to demosponges, modern sea sponges that are soft-bodied filter feeders.
- The research team compared these ancient steranes with chemicals in living sponges.
- They discovered that living demosponges still produce specific sterols matching ancient ones.
- This provides strong evidence that sponges were among the earliest animals on Earth.
- The study improves methods to determine if chemical signals in rocks come from living organisms.
