Explain what the term self-pollination means.
Explain why cross-pollination can be more advantageous to a species than self-pollination.
Maize is wind-pollinated. An investigation was done to discover how long maize pollen remains in the air affects its capacity to cause fertilisation in a female flower. Pollen grains were taken from maize flowers and exposed to air for different lengths of time. They were then applied to groups of female flowers. The fertilised flowers in the groups developed into ears, each with many seeds. The number of seeds in each ear was counted. The results are shown in Fig. 5.1.
Describe how exposure to the air affects maize pollen.
Teosinte, a wild relative of maize, grows in Mexico. There are worries that pollen from genetically-modified maize might pollinate wild teosinte and pass new genes to it. Suggest how the results shown in Fig. 5.1 could be used to plan strategies that would reduce the chance of this happening.