how does the soil bacteria could sustain the recycling of nitrogen before land plants evolved.?

Answer 1

Molecular nitrogen was not needed in atomic form before plants evolved. In the oceans and lakes there would have been nitrates and nitrites which has available atomic nitrogen when the alga metabolized it. However, soil does not have very much available nitrogen but the air is 80% molecular nitrogen (before marine and land plants it was even higher). Nitrogen-fixing bacteria (the bacteria that can break apart N2) probably evolved in tandem with land plants. The bacteria would provide nitrogen for the plants and the plants would help break down soil (a good home) and provide oxygen for the bacteria.

Answer 2

there is actual NO organic and organic imperitive to desert a jointly passable relationship referred to as symbiosis. Why make sure the thank you to do it your self while your neighbor is plenty extra effective at it and you have worked out a jointly effective barter gadget?

Answer 3

why ? not needed