Alive individual Died this age Simulated ln S(a) Theoretical ln S(a)
Cohort exhausted — press Restart
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Survivorship Curves — Type I, II & III Mortality

One of population ecology's founding tools is the survivorship curve: chart the log of a birth cohort's surviving fraction against age and the shape immediately tells you how a species spends its mortality risk. This simulator seeds a 3D cohort of instanced individuals and ages them one step at a time under a real hazard function — Type I (mortality concentrated late, like large mammals), Type II (constant hazard, a straight line on the log plot, like many birds and hydra), or Type III (mortality concentrated in infancy, like fish and insects). Each death is a genuine stochastic draw against the analytic survival probability, plotted live alongside the exact theoretical curve, while life expectancy at birth is integrated from the same hazard schedule in real time.