Neco Model Questions Vol1 2025 Biology Question 35

Ecosystem A has a primary productivity of \(1200\) g C·m⁻²·yr⁻¹. The trophic transfer efficiencies are 10 % from producers to primary consumers, 15 % from primary to secondary consumers, and 20 % from secondary to tertiary consumers. Ecosystem B has a primary productivity of \(800\) g C·m⁻²·yr⁻¹ with efficiencies 12 %, 12 % and 25 % for the same successive transfers. (a) Calculate the net carbon flow reaching tertiary consumers in each ecosystem (in g C·m⁻²·yr⁻¹). (b) In ecosystem A the tertiary consumer follows the logistic growth model \(\frac{dN}{dt}=rN\left(1-\frac{N}{K}\right)\) with intrinsic rate \(r=0.4\) yr⁻¹. Assuming the steady‑state biomass \(N\) equals the carbon flow computed in part (a), find the carrying capacity \(K\). (c) Compare the two ecosystems in terms of their ability to support tertiary consumers and give a brief ecological explanation.