The Evolution of Foraminifera

Stromatelites dominated the history of life until about one billion years ago. At that time, they were replaced with a different kind of crobial mat formation called a thrombolite. The answer may lie in the evolution of another organism known as foraminifera. Foram and ifera build tiny shells for themselves called tests. So it makes sense to wonder if they had something to do with the change in earth's microbelites.