Inheritance, variation and adaptation

Inherited or environmental?

Some features are inherited from parents — eye colour, natural hair colour, the shape of a leaf. Others are caused by the environment — a scar, a suntan, how tall a plant grows in poor soil. Many features are affected by both, and saying so is often the full-mark answer.

Variation

Individuals of the same species are not identical. Some variation is continuous (height, mass — any value in a range) and some is discontinuous (blood group, ability to roll the tongue — separate categories). Continuous data suits a line graph; discontinuous data suits a bar chart.

Adaptation

An adaptation is a feature that helps an organism survive where it lives: thick fur in cold places, deep roots in dry places, wide leaves in shady forests. Every adaptation answer must link the feature to surviving in that particular habitat, not just describe it.