What, if anything, are Foraminifera?

This is a question that I am often asked. I tend to try to keep my answer simple, so as to be as comprehensible as possible to the layman. I say that they are single-celled organisms similar to Amoebae, but differing in possessing shells.

Why should I care?

This is another question that I am often asked in one form or another (such as ‘So what?’), usually immediately after I have given my answer to the previous one. I say: on account of their numerical importance in modern environments and in the ancient rock record; and of their practical importance to Science and to Humankind, in developing an understanding of modern environments and of the ancient rock record.

Importance of Foraminifera

The number of nominal living species of Foraminifera, including synonyms, has been estimated to be at least 6000 (Jones, 1994, based on a count of those in the Ellis & Messina Catalogue), and could be considerably more (Pawlowski et al., 2003a; Murray, 2007; Lipps & Finger, 2010; Pawlowski et al., 2010; Pignatti et al., 2010). The total number of fossil and living species, again including synonyms, has been estimated to be at least 38 000. Foraminifera have been estimated to constitute approximately 2% of all the animals, or animal-like organisms, known from the Cambrian–Recent, and 38% of the animal-like protists or ‘protozoans’ (Boltovskoy & Wright, 1976).