Dr Paul Pearson used to be the Departmental contact person for WEGA and is a very good friend of the group. He has since become a Professor at  Cardiff University, his web page can be found here. He stepped in at rather short notice to give us a lecture which was a revelation to many of us. When I went to University the sediments of the deep-sea floor were dismissed as Globigerina Ooze, and no more was said. But Paul has used the multitude of tiny forams in the rock to find out much about the evolution of life.

Darwin would have dearly loved to hear this lecture for it contained much about the nuts and bolts of how one species is related to another - does one species carry on for a long time, sending off side branches at intervals. Or does one species evolve into another which itself leads to another - and so on. Most of the fossil record is totally inadequate to answer such questions. There is so much that is missing. But in some places there is a continuous sequence of sediments, containing a multitude of well preserved fossils that one can begin to ask - and answer - these questions.

The question on every geologists lips is, "How do you know that you have a complete sequence?", and the answer comes from an unexpected direction. - The Sun! The sediment cores show a variation in the clay content. The ratio of clay to carbonate can be plotted. The curve produced shows a remarkable correlation to the curve of solar radiation. The solar radiation which the earth receives varies irregularly but predictably due to various perturbations to the earths orbit relative to the sun. Establishing a correlation between the two curves can tell us if any of the sequence is missing and also the age of any part of the sequence. Presumably the amount of solar radiation affects the erosion rates of rivers flowing into the Ocean and hence the clay content. This is a satisfyingly complete result of intelligent observation.

Pauls work is very much in progress and is answering such question as "Do species change in size with time?", "Does the handedness of species change in any predictable way?" Much of it involves the patient measuring of many different parameters of the tiny shells. One can imagine many long hours hunched over a hot microscope - thank goodness for graduate students!