. Animals of land and sea. Zoology; Insects; Zoology. 158 ANIMALS OF LAND AND SEA and its progeny do the same, in the course of a single month a thousand miUions would be produced. So far as I am aware the rapidity of multiplication of the marine diatoms under optimum conditions has never been satisfactorily determined. But it has been calculated that a single diatom will give rise to a thousand millions in a month. With 6,000,000 diatoms, more or less, to a quart of water in such a locality as Kiel Bay, each one with a reproductive capac- ity of roughly 1,000,000,000 per month, all of the dia
. Animals of land and sea. Zoology; Insects; Zoology. 158 ANIMALS OF LAND AND SEA and its progeny do the same, in the course of a single month a thousand miUions would be produced. So far as I am aware the rapidity of multiplication of the marine diatoms under optimum conditions has never been satisfactorily determined. But it has been calculated that a single diatom will give rise to a thousand millions in a month. With 6,000,000 diatoms, more or less, to a quart of water in such a locality as Kiel Bay, each one with a reproductive capac- ity of roughly 1,000,000,000 per month, all of the diatoms could be destroyed ex- cept for a single one to each 166 quarts of water, yet in a month the full num- ber would be again restored. This shows clearly the immense advantage the mi- nute diatoms have over larger plants as floating organisms in the sea, and why it is that the marine vegetation except along the shores is all microscopic, and not only microscopic but extremely small. The peridinians, coccolithophorids, flagellates, etc., while very different from the diatoms in bodily form and struc- ture, are more or less similar in their relations to the marine world, so that it will not be necessary to consider them in detail. While these little plants are able to increase at a most amazing speed and at times occur in incredible abundance, this only takes place under a small range of conditions, occurring for the most part at certain limited seasons. On land in many regions when the drought is broken by the rains grasses and many other plants immediately appear in great abundance. Each grass blade is the equivalent in dry nutritive material of many million diatoms, and the synthesis or formation of nutritive material under these conditions is probably at least as rapid as it ever is at Figs. 445-450- Parasitic insects. For explanations of the figures see pp. xxiv, Please note that these images are extracted from scanned page images that may have been digitally e
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