Evolution: Human heart adapted to walking upright and thermal stress, study suggests
An international research team have completed a new study comparing human hearts to non-human great apes, revealing a new insight into human evolution.
Even though non-human great apes and humans have a common ancestor, humans have evolved the ability to run and walk upright and with larger brains, which is likely to be able to hunt more effectively.
An international research team from the University of British Columbia Okanaga Campus (UBCO) and Swansea University have suggested a new insight into human evolution by comparing the structure of the human heart to great apes.
In their study published in Communications Biology, the research team compared the human heart with great apes such as chimpanzees, gorillas, orangutangs, and bonobos from wildlife sanctuaries in Africa and zoos located throughout Europe. During routine veterinary procedures, the team used cardiac ultrasounds (echocardiography) to make images of the heart's left ventricle. In the images created for non-human great apes, the left ventricle had bundles of muscle extending into the chamber called trabeculations.
Unique ecological niche
Bryony Curry, a PhD student at the School of Health and Exercise Sciences at UBCO said “We found that the degree of trabeculation in the heart was related to the amount of deformation, rotation and twist. In other words, in humans, who have the least trabeculation, we observed comparatively greater cardiac function. This finding supports our hypothesis that the human heart may have evolved away from the structure of other non-human great apes to meet the higher demands of humans’ unique ecological niche.”
Human engagement in greater physical activity and a larger brain than other great apes can also be linked to humans having a higher metabolic demand, meaning that humans need a heart that can pump a larger amount of blood around the body. Higher blood flow can also contribute to a human’s ability to cool down, which happens by the blood vessels close to the surface of the skin dilating, giving it a flushed appearance, which then helps to lose heat to the air.
Dr Aimee Drane, a senior lecturer from the Faculty of Medicine, Health and Life Sciences at Swansea University said “In evolutionary terms, our findings may suggest selective pressure was placed on the human heart to adapt to meet the demands of walking upright and managing thermal stress."
“What remains unclear is how the more trabeculated hearts of non-human great apes may be adaptive to their own ecological niches. Perhaps it’s a remaining structure of the ancestral heart, though, in nature, form most often serves a function.”
Source of the news :
Curry, B.A., Drane, A.L., Atencia, R., Feltrer, Y., Calvi, T., Milnes, E.L., Moittié, S., Weigold, A., Knauf-Witzens, T., Sawung Kusuma, A., Howatson, G., Palmer, C., Stembridge, M.R., Gorzynski, J.E., Eves, N.D., Dawkins, T.G. and Shave, R.E. (2024). Left ventricular trabeculation in Hominidae: divergence of the human cardiac phenotype. Communications Biology.