Things Are Changing On The Top of the World
This is the Tibetan Plateau at an average elevation of 4,500 metres (14,800 ft) it's one of the highest places people live on Earth.
When Is Thick Blood A Bad Thing?
How high is the Tibetan plateau? Well, high enough that there is 40% less oxygen there than at sea level. 40%! Imagine doing any activity that leaves you breathing hard in that environment. Now, imagine that every day you need to hike into the mountains with your herds or gather dung for your fire (yes, you read right, "dung" - you'd have a hard time finding trees on the Tibetan Plateau). This is the life of many Tibetans. Their ability to live and thrive in an environment which is hard on other Homo sapiens is an irresistible question for researchers. Now, with improvements in molecular biological techniques, researchers are getting closer to understanding how Tibetans manage these incredible feats and how they differ from other humans.
- Tibetans Show Recent Evolution from AMNH http://www.youtube.com/watch?v=_IXTUns1Q68
Use the resources below to answer the following questions:
- What is a common occurrence for people traveling to the Tibetan Plateau? Does this happen to the people who live on the plateau?
- How do most people adjust to low oxygen levels in the air? Do you think this may have an energetic cost to these people? What effect does this have on their blood?
- How do Tibetans cope with a low oxygen environment? How could this condition have spread through the population? Be as specific as you can in your answer.
- How long do researchers think the Tibetan population has been separated from the Han Chinese population? Do you think the Tibetans are an example of microevolution? Why or why not?
- Researchers found 30 genes with mutations when comparing Tibetans to the Han Chinese. How many of these genes were related to oxygen and the blood? Do these findings support the idea that the genetic differences seen were related to altitude? Why or why not?