sentences:  In sexual species, oogamous meiosis produces haploid gametes, either ova or sperm cells.These fuse to produce a zygote which expands in size to develop into an auxospore from which full-sized vegetative cells are produced.In some taxonomy schemes, the centric diatoms are known instead as order Coscinodiscophyceae, and in some schemes as order Biddulphiales.