Production efficiency is highest in:
Invertebrates commonly show high production efficiency because many are ectotherms and devote relatively little assimilated energy to maintaining a constant body temperature. More energy can therefore become growth, reproduction, or new tissue. Mammals and birds incur large respiratory costs for endothermy, while fish are also ectothermic and can be efficient; consequently, the ranking is a broad textbook generalization rather than an invariant rule. Age, temperature, activity, food quality, and life history can reverse comparisons among particular species. The distinction between gross transf
Ref: Fundamentals of Ecology, Odum & Barrett, 5th Ed., Ch. 3