Debate in 1998

Regular e-mailer, Norman Macleod's, once more takes up the cudgel against those who would make extensive use of stratigraphic data.

In the final week of this Nature debate the moderator, Andrew Smith, draws together the main threads that have run through the contributions.

The responses to Norman Macleod's previous e-mail contribution were such tahe this week we have given him the opportunity to respond.

The polarization seen in this debate arises, says Dr Dan Fisher, from a desire for both sides to argue over different questions. He cautions that the zeal of cladists to discard stratigraphic data as irrelevant is in danger of throwing out the baby with the bath water.

Is the incompleteness of the fossil record any reason to exclude the information that it contains? Professor Chris Paul argues that stratigraphic data is being treated inconsistently compared to other forms of data.

A model is only as good as the assumptions and data on which it is based. Here Dr Peter Forey takes issue with earlier contributors who wish to use incomplete stratigraphic data when constructing phylogenies. He argues that these data are better employed as independent checks once a phylogenetic theory has been proposed.

One of this week's email contributors takes to task those who would hold up the foraminifera as an example of a gap free fossil record.

The fossil record contains many gaps and the quality of sampling can vary immensely over time and among taxa. But, argues Dr Peter Wagner, when constructing phylogenies no source of information should be ignored. The challenge is knowing how to weight such data.

If the fossil record cannot provide definitive answers to evolutionary questions perhaps we should be looking elsewhere. Dr Blair Hedges proposes that investigating gene sequences can reveal what fossils cannot.