Ancient Sponge Solves 550-Million-Year Mystery!

Scientists just found an incredibly old sponge fossil that's softer than any they've seen before, and it finally explains why sponges are so hard to find in the fossil record [a collection of preserved ancient remains]. This squishy ancient sponge shows us that the very first sponges didn't have hard shells to protect them, which means they mostly turned into dust instead of becoming fossils. Now scientists know exactly where to look for more missing pieces of how animals first started on Earth!