Number 12/Life & ecology/Evolution
The Variance Transfer
The quantity
The ratio of between-group variance to total variance in a trait under multi-level selection. It measures how much of the lower-level variance is available to selection above.
01Why it matters
It predicts whether higher-level selection can act at all, independent of how strong that selection is.
02Expected value
Adaptation at the higher level should stall below a transfer of roughly 0.1, regardless of selection differential.
03How it would be measured
Variance components from hierarchical sampling; standard in quantitative genetics.
04What would refute it
If higher-level response tracks selection differential regardless of transfer, the number is redundant.