Why do Females Exist?

All animals, all fish and reptiles have the ability to reproduce of their own kind because they have females within the species. No male can reproduce and keep its kind alive without a female of the same species. Dogs, cats, horses, cows, elephants, humans, giraffes, lions, tigers, birds, fish, and reptiles all came into being having both male and female. If any species came into existence without a mature female present (with complimentary female components), that one male would have remained alone and in time died. The species could not have survived without a female.

Why did hundreds of thousands of animals, fish, reptiles and birds (over millions of years) evolve a female partner (that coincidentally matured at just the right time) with each species?