Final answer:
Brachiopods are shelled, filter-feeding marine organisms that have diminished in diversity over time. The number of living species of brachiopods is relatively small compared to the fossil record.
Step-by-step explanation:
Brachiopods are shelled, filter-feeding marine organisms that come in various shapes and sizes. While their diversity was once much greater during the Paleozoic Era, there are still brachiopods living today, although their diversity is greatly diminished. The exact number of living species of brachiopods is not specified in the given information. However, based on the information provided, it can be inferred that the number of living species of brachiopods is relatively small compared to the fossil record.