WHY MILLIONS OF SPERMS CELLS .? WHEN ONLY ONE NEEDED..

I just want to write some thing which is not commonly known by people....it will be interesting to me and to u!!

Ma friend asked me...why there is millions of  sperm cells to fuse with and fertilize  one egg...he was so curious..even i was but, i answered him in ma way...i just said him its just Darwins theory ...What the hell is that,,,,there are 40 to 600 millions sperm when men ejaculate...but what is sperm cells and ..what are the parts of it ...it have 3 parts head,tail and middle piece.The head have acrosome which is a mutated lysosome which contains the enzymes which can help to penetrate ovum,the head of sperms have many  mitochondrias which are power houses..which produce energy for the movement of the tail...The tail which help to penetrate through ovum..out of 40-600 million sperm cells only one fuses...many loose the energy and die. The fact is only a small proportions of sperms fights or compete until  one get fuse with the egg(Nucleus)...After one sperm fused with the egg...other speRmS will be killed inside by a mechanism...so see the battle or competition starts from fertilization... so  a man who doesnt have a enough sperm count cant be a Biological father....But doctors have succeed in increasing the count OF SPERMS.. What i say is Darwins  THEORY will suit even to the sperm...SURVIVAL OF THE FITTEST ......We have compete with 600 millions so why cant we compete with the world?//?