Role of Environment

The phenotype is the observable characteristics or traits of an organism

  • It is predominantly determined by the organism’s genotype (allele combination) for each particular feature

However environmental factors may also influence the expression of characteristics

  • Hydrangeas change colour depending on the pH of the soil (acidic soil = blue flower ; alkaline soil = pink flower)
  • Human skin colour is determined by the expression of melanin pigment, but levels can change depending on sun exposure 

The Role of Soil pH in the Determination of Hydrangea Flower Colour

hydrangea colour