Khan PSY question

[DanniD]

Hi there is a PSY question from khan that I believe is wrong, the question is below and the answer is "Increased" and their reasoning is "The heritability of a trait increases as more trait variation is attributed to genetic variation." but heritability is Unaffected since it is transferred genetically, for example someone with blue eyes passes those genes to their child so heritability is unaffected regardless of environmental factors, it's the expression of genes that may be affected due to environmental factors. correct?
As environmental differences are more tightly controlled in a given population, the heritability of studied traits in that population is:

• Unaffected
• Increased
• Directed
• Decreased

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[bee17]

The question is asking about the heritability of studied traits in a particular population. Imagine you are a scientist studying a trait, and you do not know whether differences in that trait are inherited or whether they are due to environmental factors (or a mix of both). Tightly controlling environmental differences allows you to reduce the effect of environmental factors on traits, so the variation seen is more likely to be due to genetics, hence heritability of the train increases.

 

[DanniD]

The question is asking about the heritability of studied traits in a particular population. Imagine you are a scientist studying a trait, and you do not know whether differences in that trait are inherited or whether they are due to environmental factors (or a mix of both). Tightly controlling environmental differences allows you to reduce the effect of environmental factors on traits, so the variation seen is more likely to be due to genetics, hence heritability of the train increases.

thank you for clarification! I had the impression that genetic heritability stays constant and only the expression of traits varies based on environmental influences

 

[ChrisMack390]

Yup, it is an experimental design question, not a pure evolutionary biology question.

 

[bee17]

thank you for clarification! I had the impression that genetic heritability stays constant and only the expression of traits varies based on environmental influences

From Merriam-Webster:

"Definition of HERITABILITY
1
: the quality or state of being heritable
2
: the proportion of observed variation in a particular trait (as height) that can be attributed to inherited genetic factors in contrast to environmental ones"


I think you were assuming the question was using the first definition, when it was actually referring to the second. Height is an excellent example, as there are both genetic and environmental factors that can contribute to height.