How does the slope of the species-area relationship change when analyzing very large areas like entire continents?

It becomes steeper (higher Z values).

a) It becomes steeper (higher Z values).

When analyzing very large areas like entire continents, the slope of the species-area relationship becomes steeper. The Z values, which represent the slope of the line on the logarithmic scale, increase in this scenario. For large areas, the relationship between species richness and area shows a more rapid increase in species diversity with increasing explored area compared to smaller regions.

In other words, when studying species richness over larger geographical scales, the number of species tends to increase at a faster rate as the explored area expands. This is in contrast to smaller regions where the increase in species richness reaches a plateau or levels off after a certain point due to the finite number of species that can exist within a given area.