Practice question

When travel between patches takes a long time, leaving the current patch imposes a large period with no resource intake. The marginal value theorem therefore predicts that a forager should exploit each reached patch more thoroughly and remain there longer before departing. With short travel, frequent movement is less costly and earlier departure can be optimal. Resource-poor patches generally support shorter visits unless travel costs are extreme, and low energetic rewards do not by themselves maximize residence. The relationship arises because the optimal departure tangent is calculated over both patch exploitation and between-patch travel, so greater travel time lowers the environmental average gain rate and delays departure. From an evolutionary perspective, traits persist when their net effects improve inclusive or direct fitness under prevailing conditions. The ecological terminology therefore summarizes both an immediate mechanism and its likely consequences across generations. A careful interpretation retains the assumptions of the underlying model and avoids extending it beyond available evidence. Within those assumptions, the keyed concept gives the most consistent account of the biological pattern and its expected outcome.