Pollen grains from Tenaghi Philippon (IMAGE) Heidelberg University Caption Pollen grains from Tenaghi Philippon under the microscope. Due to their good preservability, they also remain intact in drill cores, making it possible to reconstruct vegetation and climate changes in the geological past. The pollen grains in this picture are approx. 400,000 years old. Credit Ulrich Kotthoff Usage Restrictions This image may be used only in connection with the contents of this press release, and the source of the image must also be cited. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.