Re: Early complex life

James Mahaffy (
Fri, 13 Aug 1999 13:27:14 -0500

Massie sais:
> Any comments on the USA Today article on the belief of discovery of
> evidence of earlier than thought complex life.

> Bert M.

I glanced at the article (url provided by Ryan R.) and must say the information is interesting but I would really treat it with caution. It seems that the evidence is based solely on finding steranes (used in eukaryotic membranes) in the rocks. There is a much greater problem with contamination in this type of study than most folks realize. For instance it appears that the NASA evidence for life on MARS is thought by most scientists to be contamination in the meteorites.

In this case I would like to see the chemical evidence supported by fossil evidence of eukaryotic cells done by someone like James Schopf, who is used to looking at Precambrian fossils. Or at the minimum, be skeptical if it does not appear in either Science or Nature. If really solid, this research would likely appear in either journal. It is significant enough to easily be publishable and I can not image them publishing it in a less prestigious journal (after all the goal of science is to become so well known that you will be cited after you are dead). But those journals have a pretty good review policy and I will for sure look it up if I find it there.

If I find something more on paleonet (professional list for paleontologists), I will share it with the ASA group.

James Mahaffy ( Phone: 712 722-6279
Biology Department FAX : 712 722-1198
Dordt College, Sioux Center IA 51250