The Success of Sexual Reproduction in Plants and Animals
Sexual reproduction has been successful among flowering plants and mammals, it is brought by the following requirements.
Firstly is the transfer of gametes. Sexual reproduction is only made successful when the gametes of the male and female from a pair of parents of different sexes are transferred to meet each other. In mammals, the male gamete is transferred to the female body by copulation to meet with the female gamete in the oviduct for successful fertilization. However, the ovum is only present right after ovulation occur, and it can survive for about two days, while sperms can survive 3 to 5 days. Therefore successful fertilization can only happen when copulation is close to the ovulation, and the sperm can meet the egg. But before copulation is taking place, mammals will have different courtship behaviors to attract the same species of opposite sex to have copulation with him. There are different kinds of courtship behaviors, such as singing and dancing, some mammals may also fight against each other for the same female. All the courtship behaviors are used to show that the male has more desired genetic materials and can produce strong and healthy offsprings.
In plants, the transfer of gamete is brought about by the pollinating agents. The male gamete, which is carried inside a pollen, has to land on the stigma for successful sexual reproduction to occur. Some plants use insect for pollination. They have large and brightly coloured petal to attract insects. Sticky stigma curls down to pick up the pollen grains from the insect and nectary which secretes sweet nectar to attract insects for pollinating. For wind pollination, the flowers have very long anther hanging loosely out of the flower, large number of light, small, dry and smooth pollen grains to catch wind and feathery stigmas hanging out to catch pollen grains in the air.
The healthy development of zygote and the nourishment by parent also helps with the succeed of sexual reproduction. In
Firstly is the transfer of gametes. Sexual reproduction is only made successful when the gametes of the male and female from a pair of parents of different sexes are transferred to meet each other. In mammals, the male gamete is transferred to the female body by copulation to meet with the female gamete in the oviduct for successful fertilization. However, the ovum is only present right after ovulation occur, and it can survive for about two days, while sperms can survive 3 to 5 days. Therefore successful fertilization can only happen when copulation is close to the ovulation, and the sperm can meet the egg. But before copulation is taking place, mammals will have different courtship behaviors to attract the same species of opposite sex to have copulation with him. There are different kinds of courtship behaviors, such as singing and dancing, some mammals may also fight against each other for the same female. All the courtship behaviors are used to show that the male has more desired genetic materials and can produce strong and healthy offsprings.
In plants, the transfer of gamete is brought about by the pollinating agents. The male gamete, which is carried inside a pollen, has to land on the stigma for successful sexual reproduction to occur. Some plants use insect for pollination. They have large and brightly coloured petal to attract insects. Sticky stigma curls down to pick up the pollen grains from the insect and nectary which secretes sweet nectar to attract insects for pollinating. For wind pollination, the flowers have very long anther hanging loosely out of the flower, large number of light, small, dry and smooth pollen grains to catch wind and feathery stigmas hanging out to catch pollen grains in the air.
The healthy development of zygote and the nourishment by parent also helps with the succeed of sexual reproduction. In