Researchers Shed Light on Earth’s Earliest Ecosystem
An international team of researchers led by the University of Bristol has shed light on the planet’s earliest ecosystem. It showed that within a few hundred million years of the earth’s formation, the planet was likely already flourishing with life. Every living thing today is likely descendent from a common ancestor known as LUCA or the Last Universal Common Ancestor.
LUCA is the hypothesised common ancestor that all modern cellular life, including single celled organisms such as bacteria, to giants such as the blue whale and redwood trees, as well as us, have originated from. It “represents the root of the three of life” before splitting into groups that we know today.
The researchers compared all the genes in the genome of living species, counting the mutations that have taken place within their sequences over time since they shared an ancestor in LUCA. The time of the separation of some species is known from the fossil records.
As a result, the researchers used a genetic equivalent of an equation used to calculate speed in physics. They used it to predict when LUCA likely existed, arriving at an answer of 4.2 billion years ago. That is roughly four hundred million years after the earth and our solar system formed.
The team then calculated the biology of LUCA. They did this by modelling the physiological characteristics of living species through the genealogy of life back to LUCA.
“The evolutionary history of genes is complicated by their exchange between lineages,” lead author Dr Edmund Moody explained. “We have to use complex evolutionary models to reconcile the evolutionary history of genes with the genealogy of species.”
The study also involved scientists from University College London (UCL), Utrecht University, Centre for Ecological Research in Budapest, and Okinawa Institute of Science and Technology Graduate University and was funded by the John Templeton Foundation.
