What is gamete transfer? State its necessity.

(N/A) Gamete transfer is the process of moving male gametes towards female gametes.
After the formation of gametes,male and female gametes must be physically brought together to facilitate fusion (fertilization).
In most organisms,the male gamete is motile and the female gamete is stationary. Exceptionally,in some fungi and algae,both types of gametes are motile.
Therefore,a medium is required for the transport of male gametes. In algae,bryophytes,and pteridophytes,water acts as the medium for gamete transfer.
Since a large number of male gametes fail to reach the female gametes,the number of male gametes produced is several thousand times higher than the number of female gametes to compensate for the loss during transfer.
In angiosperms,pollen grains carry male gametes and the ovule carries the egg. Therefore,pollen grains produced in the anther must be transferred to the stigma before fertilization can occur.
In self-pollinating bisexual plants like peas,the anther and stigma are located very close to each other,making the transfer of pollen grains to the stigma relatively easy,as pollen grains released from the anther come in contact with the stigma almost immediately.
However,in cross-pollinating plants (including dioecious plants),a specialized event called pollination is required to transfer pollen grains to the stigma.