“On A Piece of Chalk”‐Updated1

Abstract

ABSTRACT. Many advances have been made in our knowledge of the biology of foraminifera over the past several decades. Fine structural, biophysical, and molecular biological studies have shown that the most prominent components of their distinctive bidirectional granuloreliculopods are bundles of micro tubules linked by crossbridges to each other, as well as to membrane‐bound organelles and the plasma membrane. the microtubules ratchet past each other as dynein transduces the free energy of ATP to produce pseudopodal movements. In spite of the fact that there are over 40,000 described species of living and fossil species of foraminifera, there have been many recent exciting discoveries of new species and groups. New casting techniques are providing us with greater understanding of the complexities and functional aspects of form in the group. Significant advances are being made in understanding the distribution and energetics of deep‐sea forms. Larger and planktonic foraminifera are the hosts for a particularly diverse range of endosymbiotic algae, including dinoflagellates, chlorophytes, unicellular rhodophytes, and diatoms. Chloroplast husbandry also occurs. Significant research effort has been expended yielding us considerable insight into various aspects of the endosymbiotic phenomenon. A unified conceptual framework has been drawn to help us understand the life cycle options found in foraminifera.