Lloyd V. Berkner Memorial Symposium on Evolution Thomas L. Poulson, Ronald A. Brandon, Stewart Peck, Thomas Jegla David Culver, and Robert Mitchell. John R. Holsinger, Roger Barody, and Douglas Meaville. of the Earth’s Atmosphere (27 Dec.) Arranged by S. I. Rasool (Goddard Institute for Space Studies, New York City). ZOOLOGICAL SCIENCES(F) Both biochemical arguments and geological evidence strongly suggest that the atmosphere of the earth has under- gone major evolutionary changes during its long history. There is convincing evidence that the present atmosphere Sharing as a Genecological Process (30 Dec.) Arranged by Pierre Dansereau (New York Botanical and hydrosphere arose largely from the earth’s interior by volcanic emanations, But the sequence of events which led to present-day composition of Neo and O, has yet to be established. What is the history of volatiles now Garden, Bronx) and H. G. Baker (University of California, Berkeley). Interactions between organisms in biotic communities have more often been investigated in terms of deleterious present at the surface of the earth? Has the carbon, nitro- gen, oxygen, and hydrogen always been in the form of CO., Ns, H.O, and H., or did carbon and nitrogen combine with hydrogen early in the earth’s history to form CH, and NH,? Under what atmospheric conditions did life originate on earth and how did the appearance of life consequences than advantageous ones. There is a growing body of evidence, however, that positive interactions do occur. Very little attention has been paid to the evolutionary processes which bring about the adjustment of taxonomically distinct organisms so that they share rather than change the atmosphere? compete for natural resources. What we are concerned tive atmosphere, it is almost certain that it was devoid symposium may very well examine what evidence exists present atmospheric level during the entire prebiological increase its efficiency. H. G. Baker, Daniel Pierre Dansereau. with is the opposite of the character-displacement. The Despite disagreement over the composition of the primi- for sharing in nature and the genecological processes which of free oxygen. The late Lloyd V. Berkner and L. C. Marshall have presented detailed calculations indicating that free oxygen was limited to about 0.1 percent of the history and accumulated slowly to the present amount since the start of photosynthesis. Difficulties arise, however, when one attempts to construct an evolutionary model of the atmosphere which would be consistent from the prebiological period to the present. Some of these important questions will be discussed in the symposium. Harrison Brown, P. Cloud, S. I. Rasool, W. E, MeGovern, S. W. Fox, L. C. Marshall, and H. D. Holland. GEOLOGY AND GEOGRAPHY(E) Earth Sciences in Secondary Schools (27 Dec.) Arranged by G. Gordon Connally (Lafayette College and SUNY, College at New Paltz). John H. Moss, Kurt E. Lowe, Roger W. Ming, Irving L. Horowitz, Whitman Cross I, Harold C. Fry, Jr., Archie W. Pollock, David L. Kendall, G. Gordon Connally, Anastasia Van Burkalow, Samuel N. Namowitz, John F. Thompson, Richard P. Boekenkamp, Joseph J. Fratamico, and Kenneth F. Bick. Geography and Policy Research (30 Dec.) Arranged by Gordon E. Reckord (Division of Earth Sciences, National Research Council). Saul B. Cohen, Gordon E. Reckord, Edward M. Risley, Arch C. Gerlach, Wolfram U. Drewes, Victor Roterus, and Lewis M. Alexander. Cave Geology; Ecology of Cave Animals; and Cave Geography and Exploration (29-30 Dec.) Arranged by William B. White (Pennsylvania State University). William B. White, Victor R. Baker, George H. Deike, John M. Rutherford, Jr., G. E. Eddy, D. B. Williamson. 1350 Janzen, Lincoln Brower, and Environmental Input and Endocrine Activity (27 Dec.) _ Arranged by A. van Tienhoven (Cornell University). All the phenomena which are observed in the animal kingdom are the result of interactions between the inherited characteristics of the animal and the environment. It is the purpose of this symposium to consider a small part of these phenomena, that is, the effects of the environment, and the manner in which the environmentis able to affect the function of the endocrine system of animals. The endocrine system was selected because it is one of the coordinating systems and many interactions with the other coordinating system, that is, the nervous system, have been studied. By giving consideration to separate inputs, that is, light, touch, smell, a deeper understanding can be obtained con- cerning some of the mechanisms by which endocrine phenomena are affected. The similarities, differences, and the adaptive signficance of these phenomena will receive particular attention, as is evident from the fact that vertebrates and invertebrates are to be discussed. A. van Tienhoven, H. Karten, S. J. Berry, W. M. Hamner, P. Licht, D, Aiken, D. S. Lehrman, B. Scharrer, C. A. Barraclough, F. Engleman, F. H. Bronson, T. Eisner, B. Brockway, and W. Loher. Control Mechanisms in Morphogenesis (29 Dec.) Arranged by Malcolm S. Steinberg (Princeton University). As Johannes Holtfreter retires from teaching and turns his scholarly efforts entirely to research, his colleagues honor him through this symposium. Jane M. Oppenheimer of Bryn MawrCollege will review how our understanding of “Cells, Organizers, and Or- organization” has evolved during the past 50 years, over which Holtfreter’s important contributions have been spread. J. T. Bonner of Princeton University will discuss the evidence demonstrating chemotaxis in the cellular slime SCIENCE, VOL. 158