'I left that class going: this is it!': Meet the woman specialising in evolution

The first in a series called 'Women in Research', compiled by the Research, Innovation and Development Trust. 

Many people have only a vague idea of what they want to become when they grow up. For Eleanor Scerri, there was never any doubt. At the tender age of four, her parents took her to the Natural History Museum in London, and the seed was sown.

“I told them it was the most important day of my life,” she laughed, adding that when she was just eight, she wrote an essay on the evolution of vascular plants. 

“From a young age, I had told my parents that I wanted to study evolution. If you open the old books from my parents’ day that tackle evolution, there are all my notes in pencil in the margins! I never had any doubt about what I wanted to do with my life.”

Eleanor remembers very clearly her first year as an undergraduate when she did a credit on human evolution at the Anthropology Department.

“I left that class going: this is it! My undergraduate dissertation was about human evolution and my degrees since then have brought me to this point.” 

She could never have dreamed that her work would turn on their head the current theories of humankind’s origins. Over the course of her career, she had three key questions that haunted her: how did the species evolve in Africa; why did some of them leave; and what was their impact on the environment before agriculture?

The dominant theory of evolution says that humans originated within a single region and population in Africa. Her research has changed that model and argues that there were multiple stems of population contributing to the roots of our species. These were spread across the African continent, and at times may have even lived in South West Asia.

“The lineage that led to our species began to split off from the ancestor species between 700,000 and 1 million years ago, and we emerged as Homo sapiens around 300,000 years ago.

A hard sell

"These early human populations all carried the hallmarks of the modern human mind, but they were quite diverse and spread across Africa. The physical characteristics that define us today emerged from the interactions between these first stem populations,” she explained, “and their innovations represent the very earliest expressions of what makes us human, from art to technological development, such as the bow and arrow.”

The new theory was a hard sell, in spite of the solid arguments that had been built up to support it. From those involved in genetics to those working with fossils, all had to reconsider their data in the light of this new theory that she had driven. After several publications, including in Nature [journal], her work was not only widely accepted, but also increasingly validated.

"We need to venture beyond that circle of light if we are to find the keys" - Eleanor Scerri

“There is now a new paper appearing in Nature [journal] which looks at contemporary human DNA and confirms there are multiple stems at the root of Homo Sapiens. The reason we did not see it before is because we were looking at things in the wrong way. Now there are multiple teams from multiple fields that are taking my theory as their starting point, and it has truly become the dominant theory of human origins.

“I like to compare it to the story of the drunk looking for his lost keys on the floor under the lamplight. We need to venture beyond that circle of light if we are to find the keys!”

At the beginning of her quest, this meant exploring different places in Africa, rather than focusing on the more traditional regions.

“Whenever I got some funding, no matter how small the amount, I would jump into a rusty 4x4 with all the food I needed packed into a bag, a gas canister and a tent and I would drive into the African bush to see what I could find. Slowly, slowly I would report on all the things that I found and it built up. As a project, it started from nothing so handling multimillion research projects now is something I would never have imagined back then,” she admitted.

Indeed, while it was hard to find funds at the outset to challenge the dominant theory, over the years, the results have created a snowball effect.

She remains as driven now as she was at the beginning of her quest: “There are still so many unanswered questions. We do not know how many regions of Africa played a role in the human story. We do not know how many stem populations there were or precisely when these populations were isolated or connected. People also left Africa multiple times but those populations died out when they got to Eurasia. We don’t know why all the non-Africans today are descended from one group of people who left Africa about 50,000 years ago. 

“What was so special about that one group and their circumstances? We do not know the answer to that and it is something that we are trying to investigate.

"There are still so many unanswered questions"

For a long time, there was this idea that, before agriculture, the environment was pristine with hunter-gatherers living in harmony with nature. That picture is almost certainly not true. Hunter-gatherers were altering the location and the composition of faunal and vegetal communities. And genetics suggest that mutations like sickle cell anaemia happened way before agriculture. 

“At the moment, a major theme in ecology suggests that our current understanding of the biosphere is based on a world artificially devoid of large land animals – the so-called megafauna – that died over the last 50,000 years. These animals were essential to healthy ecosystem function, and no one can agree on why they died, for example. 

One of the projects that she is working on in Malta is a microcosm of that question: you have a small island – so you have controlled conditions – and you have a dwarf megafauna, which were nonetheless the giants in their ecosystem.

"We need to understand what drove their extinction and more about the consequences of those extinctions over the last 50,000 years.”

The questions are not academic. After all, two of the current crises – climate change and biodiversity loss – need those answers.

“How can we restore ecosystems if we do not understand what their pristine states were?

“I am very grateful to have the ability to tackle these questions and very fortunate to have a team of very clever people working for me who help me to answer them.”

Set up in 2011, the Research, Innovation and Development Trust (RIDT) seeks donations from various sectors of the community to achieve its fundamental goal of promoting excellence in all areas of study at the University of Malta. Donations to the RIDT accelerate the progress made in research and education, bringing benefits to society at large. For more information please visit www.ridt.org.mt