900 E, Biological Oceanography OLR (I 984) 31 (12)

confined to a few endemic species of mussels, scallops and the mangrove cockle; in Chile large- scale aquaculture is practiced on three mussel species and the Chilean abalone, although many more molluscs are of great commercial value. Technical, economic and sociopolitical problems associated with the modernization of aquaculture methods and the potential for underutilized species are discussed with respect to the world market and potential new markets. Centro de Invest. Mar., Univ. Austral de Chile, Valdivia, Chile. (msg)

84:6305 Zhang, Fusui, 1984. Mussel culture in China. Aq-

uaculture, 39(1/4): i-10.

The successful establishment of Mytilus edulis seed grounds along the Shandong Peninsula is attributed to leaving the kelp longline rafts in the water following harvest as attachment substrata for spat, and retaining enough mature mussels for larvae production. Mussels are cultured on rafts (50-60 m long) for 6-12 months; rafts in Jiaozhou Bay typically produce ~1500 kg of fresh mussels. The artificial rearing of spat has been enhanced by improvements in the collectors used in rearing tanks, inhibition of bacterial growth, and amelioration of larval food supply. As a result > 10 million spat/m 3 of tank water can be produced. Inst. of Oceanology, Acad. Sinica, Qingdao (Tsingtao), China. (msg)

E370. Theoretical biology and ecology

84:6306 Ferracin, Alessandro, 1981. A neutral theory of

biogenesis. Orig. Life, 11(4):369-385.

Eigen's hypothesis explaining biogenesis in Dar- winian terms (mutation and selection operating at molecular, precellular levels), while elegant, is based on assumptions unprovable and perhaps untenable. Stochastic processes alone are argued to have been sufficient to give rise to protocells, their dynamics to be understood in terms of self-assembled aggrega- tions of pre-systems. Ist. di Biol. e Zool. Gen., II Cattedra, Policlinico Umberto I, Rome, Italy. (fcs)

84:6307 Hinegardner, Ralph and Joseph Engelberg, 1983.

Biological complexity. J. theor. Biol., 104(1):7-20.

Only objects composed of definable parts are considered. Complexity is defined as 'the size of the

minimum description of an object'; number of parts is irrelevant. The bit (binary unit) is 'the unit of measure for complexity.' Eggs or seeds are not much less complex than adults, 'since development is an ordering process.' Complexity in evolution is dis- cussed; rearrangement rather than increased com- plexity has predominated since the Cambrian. The complexity of a bacterium might be 9 x 106 bits. Dept. of Biol., Univ. of California, Santa Cruz, Calif. 95064, USA. (mjj)

84:6308 Hoffman, Antoni and J.A. Kitchell, 1984. Evolution

in a pelagic planktie system: a paleobiologie test of models of multispecies evolution. Paleobiology, 10(1):9-33.

Two models of evolution in multispecies systems are evaluated, using empirical species-level data. The Red Queen model assumes evolution is driven principally by biotic interactions, while the sta- tionary model assumes evolution is influenced mostly by abiotic factors. The data sets come from 111 low- to mid-latitude Pacific DSDP sites and include origination and extinction dates for Oli- gocene to Holocene pelagic plankton (coccoliths, forams, radiolarians, diatoms, silicoflagellates, and ebridian species). Predictions of the models are outlined, especially relative to distinctive features of the paleontological record. The data do not une- quivocally support the assumptions of either model. Some reservations are discussed, particularly those concerning basic model assumptions such as con- stant effective environment. Lamont-Doherty Geol. Observ., Palisades, NY 10964, USA. (jst)

84:6309 Olson, C.B., 1981. A theory of the origin of life. Orig.

L~e, 1 !(4):353-368.

The author proposes a gradual---one polypeptide at a time--evolution of peptide synthesis. A 'transfer nucleic acid' (not specified as RNA or DNA) catalyzes the transfer of activated amino acids to amino acids in the environment, resulting in the formation of capped molecules. Further steps are an increase in the number of amino acids per cap, the evolution of messenger nucleic acids capable of specifying the sequence and composition of peptide caps, ribosomal nucleic acid evolution, and codon length refinement, leading to the present triplet code. Proposed replication processes and 'environmental retention and redistribution mechanisms' (cell wall, cell division) are discussed. 416 Leland Ave., Palo Alto, Calif. 94306, USA. (msg)