Question

Adult lactose tolerance is the result of biocultural evolution, where humans impact the environment which causes new selective forces to act on our traits.

Describe how cultural practices affected the evolution of adult lactose tolerance.

Answer 1

Ans ) adults thousands of years ago developed tolerance to milk due to conditions of famine .

When humans started agriculture and cultivation first in Europe thousands of years ago ,the first set of crops probably failed due to the shorter growing season which caused famine . In such conditions people in famine affected regions started consuming milk for nutrition. In famine conditions , malnourished individuals must have consumed milk and survived to preserve the mutated lactose intolerance gene.

Early africans were cattle herders when humans migrated all over the world they started domestication of animals and cattles for labour and thus started drinking milk and the lactose intolerance gene evolved .

In parts of Northern europe where the climatic conditiins are cold , with no exposure to sunlight and lack of vitamin D ,which causes decreased absorption of calcium , milk consumption provides sufficient calcium in diet .

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