At any rate, it just comes to a logical conclusion that the more people there are, the less other species there will be, unless somehow or other we can synthesize more elements, molecules, etc. out of basically nothing. The mass of the planet is simply the mass of the planet. It is quite constant and the only change is the dust it collects from space and the odd meteorite or something. More of one thing means less of another.
BTW, the mass of the Earth is approximately
5.9742 × 10 to the 24th kilograms