Figure 7. An invasion simulation of Darwinian dynamics in the threshold PGG which is approximated by 
where 
.
(Upper-left) Evolution of the frequencies of the ESS and the invader strategy starting from 
and 
respectively. (Upper-right) Evolution of the ESS and the invader strategy starting from 
and 
and ending up with the former evolving to the latter. (Lower) Evolution of the adaptive landscape and the two strategies: 
(i.e., before the invasion happens), 
is the global maximum; 
(i.e., the invasion happens), the adaptive landscape is elevated with 
being the global minimum and 
being the local maximum; 
, the “ESS” climbs up towards the invader strategy with the latter keeping sitting at the local maximum of the reshaped adaptive landscape; 
, the “ESS” coincides with 
and reaches the top of the reshaped adaptive landscape, which means the success of the invader strategy and the failure of the “ESS”. Parameters: 
, 
, and 
.