Field conference on Niagaran reefs in the Chicago region

Held in connection with the 35th Annual Convention of the American Association of Petroleum Geologists at Chicago, April 28, 1950

Letter to A.B. Stenzel from H.A. Lowenstam on 1948-06-24

Jackson School of Geoscience

Letter to H.B. Stenzel from H.A. Lowenstam on 1963-05-28

Jackson School of Geoscience

Letter to H. Stenzel from H.A. Lowenstam on 1964-06-02

Jackson School of Geoscience

Letter to H.B. Stenzel from H.A. Lowenstam on 1948-07-23

Jackson School of Geoscience

Evolutionary Prerequisites for Early Phanerozoic Calcareous

This paper develops the concept that the dramatic appearance of calcareous skeletons in the Lower Cambrian is directly related to the origin of refined mechanisms of intracellular modulation of calcium ion concentration. An homologous family of calcium modulated proteins has recently been discovered. These proteins contain “EF hands”, involved in the maintenance of low concentrations of intracellular calcium and the informational use of calcium ion flow (Kretsinger, 1977). The evolution of this specialized calcium physiology, especially in muscle systems, coupled with natural selection by predators are identified as some of the preadaptations for the impressive Tommotian diversification of calcified metazoans. The distribution of calcium biominerals in the phyla of the five kingdoms and the time of first appearance of calcareous mineralization in the fossil record are tabulated. Macroscopic calcified hard parts apparently required the prior evolution of certain cell, tissue and organ system physiologies which are briefly discussed here