NGSS HS-LS3-3: Apply concepts of statistics and probability to explain the variation and distribution of expressed traits in a population.
Adjust the genetic and environmental factors to see how they influence the expressed height of a plant population (n = 10,000).
The average height dictated purely by the population's DNA.
How widely the genetics vary around the mean (Standard Deviation).
Most complex traits (like height, skin color, or yield) are polygenic (controlled by many genes) and follow a normal distribution (bell curve). The genetic potential sets the baseline and variance for the population. However, environmental factors (like a drought) can shift the entire distribution curve, changing the resulting expressed traits (phenotype) even without altering the underlying DNA.