The human genome is about 770 MB, the C. elegans genome is about 100 MB, the yeast S. cerevisiae is about 12 MB. Different other genomes have been sequenced: how many GB of genomic DNA we have now?
Let say we would like to make a Noah hard-disk ark: how much space would it take to represent the genomes of all known species on earth? There is a way to provide an estimate?
I'm also interested in the total biodiversity: for instance, if two species each have 1 GB genomes and have half of their DNA in common this would count as 1.5 GB.