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XVII.—Quantitative Evolution. VII. The Diatoms

Published online by Cambridge University Press:  11 June 2012

James Small
James Small
Affiliation:
Queen's University, Belfast.
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Extract

A Summary of the facts with numerical details omitted can be given as follows. In the diatoms—

1. Species-lifetimes have been alternatively short or long.

2. The main ratios of shorts to longs, or evanescents to permanents, e/p, are 3:1 for Centrales, 10:6 for Fragilariaceæ, 7:9 for allogamous Pennales. These ratios or nearest approaches to these ratios occur in the above three groups, (a) in each group as a whole; (b) in species-arising in each group per geological subperiod; and (c) in heterogeneous genera in each genus as a whole and in each genus per subperiod. A derivative 1:3 ratio also occurs in some pennate genera. There are some significant and understandable exceptions.

Type
Research Article
Information
Proceedings of the Royal Society of Edinburgh, Section B: Biological Sciences , Volume 62 , Issue 2 , 1946 , pp. 128 - 131
Copyright
Copyright © Royal Society of Edinburgh 1946

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References

References to Literature

Mills, F. W., 1935. An Index to the Genera and Species of Diatomaceœ, London.Google Scholar
Small, J., and Johnston, I. K., 1937. “Quantitative Evolution in Compositæ,” Proc. Roy. Soc. Edin., LVII, 26–54.Google Scholar
Small, J., 1937. “Quantitative Evolution.” III. Dp-ages of Gramineæ,” Proc. Roy. Soc. Edin., LVII, 221–227.Google Scholar