Infinitely abundant fossils - the unique evolutionary record of planktonic microfossils - and some new perspectives from molecular studies

Friday seminar by: Jeremy Young

Abstract

 

Geology assuredly does not reveal any such finely-graduated organic chain; and this, perhaps, is the most obvious and serious objection which can be urged against the theory. The explanation lies, as I believe, in the extreme imperfection of the geological record."/ Darwin (1859). In this well-known quote from the Origin of Species (chapter 9) Darwin outlined the possible objection to his theory, that the fossil record provides much less clear evidence of evolutionary transition between species than might at first be expected; and the prime explanation that the fossil record of most species is at best very incomplete. What Darwin did not know is that a major exception to this pattern is provided by planktonic fossils and especially planktonic microfossils such as, coccolithophores, planktonic foraminifera and radiolaria.

The mineralised shells of these organisms are continuously deposited on the sea floor accumulating as deep sea sediments which provide a continuous record of their evolutionary history. Moreover, this record has been extensively sampled especially through the Deep Sea Drilling Project and Ocean Drilling Project. These projects have accumulated hundreds of kilometres of cores from across the world's ocean containing trillions of microfossils, providing an essentially infinite resource for study of evolutionary pattern and process. This talk will review the degree to which study of this exceptional fossil record has provided evidence for gradualistic evolutionary change, and discuss the new insights to this record being provided by integration of independent data from molecular phylogenetic studies of planktonic micro-organisms.

Jeremy R. Young
Palaeontology Department
The Natural History Museum
London

Published Feb. 3, 2012 3:10 PM - Last modified Feb. 3, 2012 3:10 PM