Reproduction

Pull a strawberry plant out of a bed in late summer and you will find it trailing a thin horizontal stem across the soil, with a small rooted plant at the far end. That little plant had no other parent. Every base in its DNA came from the plant you are holding. A few metres away, a bee is carrying pollen between two flowers, and the seed that results from that visit will carry instructions from two different individuals. Both events are reproduction, and the difference between them shapes almost everything that follows in genetics.

This lesson takes the two forms apart. You will see what a gamete is and what actually happens when two of them fuse, why that fusion produces offspring that resemble their parents without copying either of them, and why reproduction from a single parent gives offspring so alike that biologists call them clones. Then you will weigh the two against each other the way this board does: not asking which is better, but asking which one wins in a particular field, on a particular farm, in a particular changing climate. It is a short piece of specification with a long reach, and the Extension Tier biology paper spends fifteen marks on it in a single question.