Mean body size in marine animals has increased more than 100-fold since the Cambrian, a discovery that brings to attention the key life-history parameters of lifespan and growth rate that ultimately determine size. Variation in these parameters is not well understood on the planet today, much less in deep time. Here, we present a new global database of maximum reported lifespan and shell growth coupled with body size data for 1 148 populations of marine bivalves and show that (i) lifespan increases, and growth rate decreases, with latitude, both across the group as a whole and within well-sampled species, (ii) growth rate, and hence metabolic rate, correlates inversely with lifespan, and (iii) opposing trends in lifespan and growth combined with high variance obviate any demonstrable pattern in body size with latitude. Our observations suggest that the proposed increase in metabolic activity and demonstrated increase in body size of organisms over the Phanerozoic should be accompanied by a concomitant shift towards faster growth and/or shorter lifespan in marine bivalves. This prediction, testable from the fossil record, may help to explain one of the more fundamental patterns in the evolutionary and ecological history of animal life on this planet.

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We investigated group velocities and group velocity dispersion characteristics of photonic crystal waveguides and coupled resonator optical waveguides(CROW's). In photonic circuits comprised of the linear defect waveguides, the insertion of the CROW section suppresses energy flow due to its highly dispersive characteristics. We analyze the change in the group velocity and the group velocity dispersion by varying the radius of the holes in the waveguide channel. Properly designed CROW sections provide a wide range of control in the group velocity and positive/negative group velocity dispersion. They can be used as delay lines or dispersion compensators in photonic integrated circuits comprised of linear defect photonic crystal waveguides.

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