(a)(i) Explain the term courtship behaviour in animals.
(ii) How does courtship aid reproduction in animals?
(b) Describe the process of fertilization in flowering plants.
Explanation
(a)(i) Courtship behaviour in animals consists of instinctive behaviours in response to certain external stimuli. The behaviour is usually carried out in sequence and alternately performed by male and femal organisms. Each step acts as a stimulus for the next step. It may involve territorial defence, display and pairing. Examples are found in some birds, fishes and mammals.
(ii) When courtship behaviour coincides with ovulation or reproduction period, mating occurs, leading to release of gametes and, therefore, increase in the chances of fertilization or reproduction.
(b) The flower possesses pollen grains which contain the male gametes and the ovules have the female gamete. The pollen grains are transferred from the pollen sac or anther to the stigma during pollination. On the stigma, the pollen grain absorbs sugary fluid and swells until the extine bursts and intine grows into a pollen tube along the style. The nucleus divides into tube and generative nuclei. The generative nucleus divides into two male gametes. One male gamete fuses with the egg cell or Ovum to form Zygote while the other male gamete fuses with pollar nuclei to form the endosperm nucleus which matures to form the nutritive endosperm. The Zygote forms the embryo after several divisions. The whole ovule becomes the seed and the ovary becomes fruit.