These little workers did not just eat a lot; they are also fast to reproduce themselves. In only 10 days they can produce a million more of themselves! Can you imagine if humans could do that? The earth would be too small for all of us! There would be no room left. So just imagine how busy everything was under the water all those millions of years ago. When the little creatures died they dropped their calcium body and add to the earth around the coast lines of the ocean. Even today, the same kind of things happens in the ocean. If you walk along the ocean beach, you’ll find that there are seashells left behind by the water that has washed them onto the shore. Tiny pieces of rocks and minerals and seashells that have been ground up by the waters of the ocean make up the sandy beaches we walk on.