Humans are still evolving, adapting to our surroundings with changes recorded in our biology. Some environments can be tough for us—like high altitudes where mountain climbers often experience altitude sickness. This is due to a drop in atmospheric pressure, which reduces oxygen intake with each breath.
Yet, on the Tibetan Plateau, where oxygen levels are significantly lower, people thrive. Over more than 10,000 years of inhabiting this harsh environment, Tibetan highlanders have developed remarkable adaptations. These changes help them combat long-term oxygen deficiencies, commonly causing hypoxia in others.
Anthropologist Cynthia Beall from Case Western Reserve University in the US describes this adaptation as a prime example of our species’ significant biological variation and resilience under extreme stress.
Beall’s recent research, published in 2024, highlights specific adaptations in Tibetan populations, particularly in women. She examined 417 women living above 3,500 meters, measuring their hemoglobin levels, which indicate how efficiently oxygen is carried in the blood.
Interestingly, these women, who had the highest live birth rates, didn’t have high or low hemoglobin levels. Instead, they boasted average levels with high oxygen saturation. This trait allows optimal oxygen delivery without making the blood too thick, which could strain the heart.
Moreover, women with enhanced reproductive success also showed increased blood flow to the lungs and larger left heart ventricles, promoting better oxygen distribution throughout the body.
In summary, this study reveals the fascinating, ongoing process of natural selection. Although cultural factors play a role, these physical adaptations are pivotal for survival. As Beall notes, understanding these adaptations offers valuable insights into human evolution.
The findings were published in the Proceedings of the National Academy of Sciences.
Vocabulary List:
- Altitude /ˈæl.tɪ.tjuːd/ (noun): The height of an object or point in relation to sea level or ground level.
- Hypoxia /haɪˈpɒk.si.ə/ (noun): A condition in which there is inadequate oxygen supply to the tissues.
- Resilience /rɪˈzɪl.jəns/ (noun): The capacity to recover quickly from difficulties; toughness.
- Adaptation /ˌæd.əpˈteɪ.ʃən/ (noun): A change or the process of change by which an organism or species becomes better suited to its environment.
- Saturation /ˌsætʃ.əˈreɪ.ʃən/ (noun): The state or process that occurs when no more of something can be absorbed combined with or added.
- Distribution /ˌdɪs.trɪˈbjuː.ʃən/ (noun): The action of sharing something out among a number of recipients.
How much do you know?
What is one environment mentioned in the text that can be tough for humans due to a drop in atmospheric pressure?
What do Tibetan highlanders who have inhabited the Tibetan Plateau for over 10,000 years develop to combat long-term oxygen deficiencies?
What did Anthropologist Cynthia Beall study in Tibetan women to understand their adaptations to high altitudes?
What physiological trait did the Tibetan women with the highest live birth rates exhibit?
According to the study mentioned in the text, what trait do women with enhanced reproductive success show in terms of blood flow?
Which publication featured the findings of the research discussed in the text?
Humans are no longer evolving according to the text.
Tibetan highlanders do not have any remarkable adaptations despite living in a harsh environment.
The study by Anthropologist Cynthia Beall focused on measuring women's vitamin intake at high altitudes.
Women with the highest live birth rates had low hemoglobin levels according to the text.
Enhanced reproductive success in women did not show any changes in blood flow to the lungs.
Cultural factors play a significant role in the physical adaptations discussed in the study.
According to the text, Tibetan highlanders have inhabited the Tibetan Plateau for over 10,000 years, developing remarkable adaptations to combat long-term oxygen deficiencies, commonly causing in others.
Anthropologist Cynthia Beall examined 417 women living above 3,500 meters, measuring their hemoglobin levels, which indicate how efficiently oxygen is carried in the .
Women with enhanced reproductive success showed increased blood flow to the , promoting better oxygen distribution throughout the body.
The findings of the study by Cynthia Beall were published in the Proceedings of the National Academy of .
According to Anthropologist Cynthia Beall, understanding these adaptations offers valuable insights into human .
Tibetan women with high live birth rates exhibited average hemoglobin levels with high oxygen saturation, allowing optimal oxygen delivery without making the blood too , which could strain the heart.
