Cutting edge simulations unveil clues to human evolution
University of Liverpool
The University of Liverpool has led an international team of scientists to take a fresh look at the running capabilities of Australopithecus afarensis, the early human ancestor famously represented by the fossil ‘Lucy’.
Karl Bates, Professor of Musculoskeletal Biology, convened experts from institutions across the UK and the Netherlands. Together they used cutting-edge computer simulations to uncover how this ancient species ran, using a digital model of ‘Lucy’s’ skeleton.
Previous work on the fossilized footprints of Australopithecus by multiple research teams has suggested that Lucy probably walked relatively upright and much more like a human than a chimpanzee. These new findings demonstrate that Lucy’s overall body shape limited running speed relative to modern humans and therefore support the hypothesis that the human body evolved to improve running performance, with top speed being a more critical driver than previously thought.
Professor Bates said: “When Lucy was discovered 50 years ago, it was by far the most complete skeleton of an early human ancestor. Lucy is a fascinating fossil because it captures what you might call an intermediate stage in Homo sapiens’ evolution. Lucy bridges the gap between our more tree-dwelling ancestors and modern humans, who walk and run efficiently on two legs.
“By simulating running performance in Australopithecus and modern humans with computer models, we’ve been able to address questions about the evolution of running in our ancestors.
“For decades scientists have debated whether more economical walking ability or improved running performance was the primary factor that drove the evolution of many of distinctly human characteristics, such as longer legs and shorter arms, stronger leg bones and our arched feet. By illustrating how Australopithecus walked and ran, we have started to answer these questions.”
The team used computer-based movement simulations to model the biomechanics and energetics of running in Australopithecus afarensis, alongside a model of a human. In both the Australopithecus and human models, the team ran multiple simulations where various features thought to be important to modern human running, like larger leg muscles and a long Achilles Tendon, were added and removed, thereby digitally replaying evolutionary events to see how they impact running speed and energy use.
Muscles and other soft tissues are not preserved in fossils, so palaeontologists don’t know how large ‘Lucy’s’ leg muscles and other important parameters were. However, these new digital models varied the muscle properties from chimpanzee-like to human-like, producing a range of estimates for running speed and economy.
The simulations reveal that while Lucy was capable of running upright on both legs, her maximum speeds were significantly slower than those of modern humans. In fact, even the fastest speed the team predicted for Lucy (in a model with very human-like muscles) remained relatively modest at just 11mph (18kph). This is much slower than elite human sprinters, which reach peak speeds of more than 20mph (38kph). The models show the range of intermediate (‘jogging’) speeds that animals use to run longer distances (‘endurance running’) was also very restricted, perhaps suggesting that Australopithecus didn’t engage in the kind of long-distance hunting activities thought to be important to the earliest humans.
Professor Bates continued: “Our results highlight the importance of muscle anatomy and body proportions in the development of running ability. Skeletal strength doesn’t seem to have been a limiting factor, but evolutionary changes to muscles and tendons played a major role in enhancing running speed and economy.
“As the 50th anniversary of Lucy’s discovery is celebrated, this study not only sheds new light on her capabilities but also underscores how far modern science has come in unravelling the story of human evolution.”
The study, ‘Running performance in Australopithecus afarensis’ was published in Current Biology (DOI:10.1016/j.cub.2024.11.025).
Journal
Current Biology
Article Title
Running performance in Australopithecus afarensis
Article Publication Date
6-Jan-2025
DNA adds new chapter to Indonesia’s layered human history
University of Adelaide
image:
Senggo Village, Mappi Regency, Papua, Indonesia.
view moreCredit: Gludhug Purnomo
A new study from the University of Adelaide and The Australian National University (ANU) has outlined the first genomic evidence of early migration from New Guinea into the Wallacea, an archipelago containing Timor-Leste and hundreds of inhabited eastern Indonesian islands.
The study, published in PNAS, addresses major gaps in the human genetic history of the Wallacean Archipelago and West Papuan regions of Indonesia – a region with abundant genetic and linguistic diversity that is comparable to the Eurasian continent – including the analysis of 254 newly sequenced genomes.
In combination with linguistic and archaeological evidence, the study shows that Wallacean societies were transformed by the spread of genes and languages from West Papua in the past 3,500 years – the same period that Austronesian seafarers were actively mixing with Wallacean and Papuan groups.
“My colleagues at the Indonesian Genome Diversity Project have been studying Indonesia’s complex genetic structure for more than a decade, but this comprehensive study provides confirmation that Papuan ancestry is widespread across Wallacea, pointing to historical migrations from New Guinea,” says lead author Dr Gludhug Ariyo Purnomo, from the University of Adelaide’s School of Biological Sciences.
“By connecting the dots between genetics, linguistics, and archaeology, we now recognise West Papua as an important bio-cultural hub and the launching place of historical Papuan seafarers that now contribute up to 60% of modern Wallacean ancestry.”
Genomic research is also becoming increasingly important for developing new medicines tailored to specific genetic backgrounds.
“In the era of precision medicine, understanding the genetic structure of human groups is vital for developing treatments that are helpful rather than harmful, with Wallacea and New Guinea having been poorly represented in past genomic surveys,” Dr Purnomo says.
Associate Professor Ray Tobler, from ANU, says Wallacea had been isolated for more than 45,000 years since the arrival of the first human groups, and the more recently arriving Papuan and Austronesian migrants reconfigured Wallacean culture by introducing new languages that diversified and intermingled to create its rich linguistic landscape.
“Our findings suggest that the Papuan and Austronesian migrations were so extensive that they have largely overwritten the ancestry of the first migrants, making the recovery of these ancient migrations from genetic data challenging,” says Professor Tobler, who is also an Adjunct Fellow at the University of Adelaide’s Australian Centre for Ancient DNA.
According to the researchers, there are challenges in reconstructing past movements of people using modern genetic data due to historical migrations and movements.
“There's also been so much movement in Wallacea in the past couple of thousand years, due to the spice trade and slavery, that it obscures the relationship between geography and genetics,” Associate Professor Tobler says.
“What we know about Wallacea and New Guinea is just the tip of the iceberg, but the use of ancient DNA can help to overcome some of these challenges and help us to understand the origins and legacy of human journeys to the region stretching back tens of thousands of years.”
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