Medical Research Council - London Institute of Medical Sciences

is the new name of the MRC Clinical Sciences Centre

BPoD is 5

In 2017 we celebrate five years of bringing you beautiful imagery from biomedical science

Born on this Day in 1928 Revolution in Evolution
15 July 2017

Revolution in Evolution

Until the mid 1970s, it was thought that organisms fall into one of two categories. Carl Woese, pictured here working on an X-ray film, revealed the 'third domain' of life. Before Woese’s discovery, lifeforms were split into eukaryotes – organisms with one or more cell containing DNA in a distinct area called the nucleus, and prokaryotes – microscopic single-celled organisms, like bacteria, without a defined nucleus. Woese pioneered a technique which allowed distinction between different prokaryotic species according to variable regions of RNA. In 1977 he used this technique to identify what he called “archaebacteria”, now known as archaea. Archaea are prokaryotes because they have no nucleus, but they have genes and metabolic pathways similar to eukaryotes. Archaea might be thought of as prokaryotes that are not bacteria. Today, because of Woese’s work, scientists group organisms into a 'Tree of Life' with three domains, or branches – bacteria, archaea and eukarya.

Written by Charlotte Rose Davison

Search The Archive

Submit An Image

What is BPoD?

BPoD stands for Biomedical Picture of the Day. Managed by the MRC London Institute of Medical Sciences (the new name for the MRC Clinical Sciences Centre) the website aims to engage everyone, young and old, in the wonders of biomedicine. Images are kindly provided for inclusion on this website through the generosity of scientists across the globe.

Read More