Organelles continue to live after the cells in which they were located die. This was discovered by a team of scientists from the University of Bristol.
Organelles such as nuclei and chloroplasts are not found in bacteria and were thought to disintegrate too quickly to become fossilized.
However, researchers at the Bristol School of Earth Sciences were able to document the breakdown of eukaryotic algal cells: they showed that nuclei, chloroplasts, and pyrenoids (organelles found in chloroplasts) could persist for weeks and months after cell death in eukaryotic cells.
The authors characterized the transformation of organelles into something resembling snot:
I spent several weeks photographing algal cells as they decayed, and also checking the condition of nuclei, chloroplasts and pyrenoids. From this, it can be concluded that these organelles do not disintegrate immediately after cell death, but in fact, dissolve over many weeks.
Emily Carlisle, Graduate Student, Bristol School of Geosciences
Historically, complex cell walls have been used to identify early eukaryotes. But some bacteria can grow to a large size, so the decoration of the cell walls can disappear under the influence of erosion.
The study’s authors argue that they can prove complex life around 1,700 million years ago to clarify evolutionary history with greater precision and clarity.