Explain what is meant by the term self-pollination.
Explain why cross-pollination may be more advantageous to a species than self-pollination.
In maize, wind pollination occurs. An investigation was done to discover how the length of time maize pollen remains in the air affects its ability to achieve fertilisation in a female flower. • Pollen grains were taken from maize flowers and left exposed to the air for different lengths of time. • The pollen grains were then applied to groups of female flowers. • The groups of fertilised flowers developed into ‘ears’, each containing many seeds. • The number of seeds per ear was counted. The findings are shown in Fig. 5.1.
Describe the impact of exposure to the air on maize pollen.
A wild relative of maize, called teosinte, grows in Mexico. There are worries that pollen from genetically-modified maize could fertilise 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 lower the chance of this happening.