Human Adaptations to Extreme Environments: Lessons from the Haenyeo Divers of Jeju Island
Survival on our planet requires adaptation, not just of the mind, but of the body. Over generations, humans have evolved to thrive in different environmental conditions, optimizing traits to enhance our ability to live and thrive. One such fascinating example of human adaptation can be seen in the genetic tracers found in the Haenyeo divers of South Korea’s Jeju Island.
The Haenyeo are women who free-dive into frigid waters year-round to harvest food from the seafloor. For centuries, Jeju Island relied on the work of these extraordinary women. However, with the decline in the need for their services, the Haenyeo population is aging, with most women being around 70 years old – possibly the last generation to carry on this tradition.
Geneticist Melissa Ilardo of the University of Utah, who has spent years studying human adaptations to extreme environments, has been intrigued by the genetic adaptations of the Haenyeo divers. In a study published in 2018, Ilardo and her colleagues identified genetic variations in the Bajau Laut people of Southeast Asia that are associated with ocean free-diving.
To investigate if similar adaptations exist in the Haenyeo divers of Jeju Island, Ilardo conducted a study involving 91 participants, including Haenyeo divers, Jeju locals who are not divers, and individuals from Seoul on mainland Korea. The study revealed that while there was no genetic difference between the Haenyeo divers and other locals on Jeju Island, the Jeju population had a genetic variation linked to lower blood pressure, which is crucial for free-diving.
The lower blood pressure in the Jeju population is believed to help mitigate the risks of high blood pressure, particularly during pregnancy, as Haenyeo women continue diving even while pregnant. This adaptation may also have additional benefits, as the stroke mortality rate on Jeju Island is lower compared to other parts of Korea.
Another genetic difference observed in the Haenyeo divers relates to their pain tolerance for cold, potentially making them less susceptible to hypothermia during their year-round dives. Additionally, the study found that the Haenyeo divers exhibited a significant decrease in heart rate during a simulated dive, suggesting that this response is a learned behavior developed through years of experience.
The findings of this study not only shed light on the remarkable adaptations of the Haenyeo divers but also provide valuable insights into how the human body responds to environmental pressures. Understanding these genetic changes could lead to the development of therapeutics for conditions such as hypertensive disorders of pregnancy and stroke.
This research, published in Cell Reports, highlights the incredible resilience and adaptability of the human body, offering valuable lessons from the Haenyeo divers of Jeju Island. The Impact of Climate Change on Biodiversity
Climate change is one of the most pressing issues facing our planet today, and its effects are being felt in ecosystems around the world. One of the most significant impacts of climate change is its effect on biodiversity, as rising temperatures, changing weather patterns, and other environmental factors are putting many species at risk of extinction.
One of the ways in which climate change is impacting biodiversity is through habitat loss. As temperatures rise, many species are finding it difficult to survive in their current habitats. For example, polar bears are losing their sea ice habitats as the ice melts due to warming temperatures. This loss of habitat can lead to decreased populations and even extinction for some species.
In addition to habitat loss, climate change is also affecting the availability of food and water for many species. Changes in weather patterns can disrupt the timing of natural events such as migration and breeding, making it difficult for some species to find the resources they need to survive. This can lead to declines in population size and reproductive success, further putting species at risk.
Another way in which climate change is impacting biodiversity is through the spread of invasive species. As temperatures rise, some species are able to expand their ranges into new areas, where they can outcompete native species for resources. This can lead to declines in native species populations and changes in the composition of ecosystems.
Climate change is also causing shifts in the distributions of many species. As temperatures warm, some species are moving towards the poles or to higher elevations in search of suitable habitats. This can lead to changes in the interactions between species and disruptions in ecosystem functioning.
Overall, the impacts of climate change on biodiversity are complex and far-reaching. In order to address these impacts and protect species at risk of extinction, it is crucial that we take action to reduce greenhouse gas emissions and mitigate the effects of climate change. By working together to address this global challenge, we can help to safeguard the incredible diversity of life on our planet for future generations.
