Computer modeling has become a more and more important tool for science. We have seen it in Climatology for decades, as well as in a number of other fields. People who have a poor understanding of science, or who are trying to deny science, such as creationists and climate change deniers, will often claim that it isn’t really real science, but that is of course pure nonsense, as empirical evidence has demonstrated it again and again.
Now, there is a new great example of how a computer model is advancing our understanding of science. As ScienceDaily reports:
First hominin muscle reconstruction shows 3.2 million-year-old ‘Lucy’ could stand as erect as we can
A Cambridge University researcher has digitally reconstructed the missing soft tissue of an early human ancestor — or hominin — for the first time, revealing a capability to stand as erect as we do today.
Dr Ashleigh Wiseman has 3D-modelled the leg and pelvis muscles of the hominin Australopithecus afarensis using scans of ‘Lucy’: the famous fossil specimen discovered in Ethiopia in the mid-1970s.
…
Wiseman was able to use recently published open source data on the Lucy fossil to create a digital model of the 3.2 million-year-old hominin’s lower body muscle structure. The study is published in the journal Royal Society Open Science.
The research recreated 36 muscles in each leg, most of which were much larger in Lucy and occupied greater space in the legs compared to modern humans.
For example, major muscles in Lucy’s calves and thighs were over twice the size of those in modern humans, as we have a much higher fat to muscle ratio. Muscles made up 74% of the total mass in Lucy’s thigh, compared to just 50% in humans.
Paleoanthropologists agree that Lucy was bipedal, but disagree on how she walked. Some have argued that she moved in a crouching waddle, similar to chimpanzees — our common ancestor — when they walk on two legs. Others believe that her movement was closer to our own upright bipedalism.
Research in the last 20 years have seen a consensus begin to emerge for fully erect walking, and Wiseman’s work adds further weight to this. Lucy’s knee extensor muscles, and the leverage they would allow, confirm an ability to straighten the knee joints as much as a healthy person can today.
The paper can be found at the Royal Society Open Science: Three-dimensional volumetric muscle reconstruction of the Australopithecus afarensis pelvis and limb, with estimations of limb leverage
Abstract
To understand how an extinct species may have moved, we first need to reconstruct the missing soft tissues of the skeleton, which rarely preserve, with an understanding of segmental volume and muscular composition within the body. The Australopithecus afarensis specimen AL 288-1 is one of the most complete hominin skeletons. Despite 40+ years of research, the frequency and efficiency of bipedal movement in this specimen is still debated. Here, 36 muscles of the pelvis and lower limb were reconstructed using three-dimensional polygonal modelling, guided by imaging scan data and muscle scarring. Reconstructed muscle masses and configurations guided musculoskeletal modelling of the lower limb in comparison with a modern human. Results show that the moment arms of both species were comparable, hinting towards similar limb functionality. Moving forward, the polygonal muscle modelling approach has demonstrated promise for reconstructing the soft tissues of hominins and providing information on muscle configuration and space filling. This method demonstrates that volumetric reconstructions are required to know where space must be occupied by muscles and thus where lines of action might not be feasible due to interference with another muscle. This approach is effective for reconstructing muscle volumes in extinct hominins for which musculature is unknown.
The paper is an interesting read and in my opinion fairly accessible.