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#bottom-up control

3 public questions tagged with this topic.

Controls Ecosystem

Accurately represents bottom-up control?

“Increased nutrients increase primary producer biomass” for accurately represents bottom-up control. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. Ecosystem processes are constrained by energy conservation and by the cycling of matter. Energy enters mainly through primary production, is lost as metabolic heat at every transfer, and therefore cannot be recycled in the way that carbon, nitrogen, phosphorus, or water can. The remaining alternatives—“Increase carnivores decreases herbivores”, “Remov

Ref: Fundamentals of Ecology, Odum & Barrett, 5th Ed., Ch. 4

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Controls Ecosystem

Does NOT influence primary productivity in bottom-up control?

The keyed exception is “Predators.” In the context of does not influence primary productivity in bottom-up control, that statement differs from the governing ecological pattern and must be evaluated against the mechanism rather than accepted from wording alone. The relevant inference should follow the pathway from resource supply to organismal uptake and then to ecosystem-level flux. Productivity, trophic transfer, decomposition, and nutrient regeneration are connected, but each measures a different part of that pathway. The remaining alternatives—“Nutrients”, “Light”, “Water”—refer to differe

Ref: Fundamentals of Ecology, Odum & Barrett, 5th Ed., Ch. 4

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Controls Ecosystem

What controls biomass accumulation in bottom-up control?

“Nutrients and abiotic factors” for what controls biomass accumulation in bottom-up control. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. Rates depend on temperature, moisture, substrate quality, consumer physiology, and the elemental balance between organisms and their food. These controls explain why the same process can differ among terrestrial, freshwater, and marine systems without changing its definition. The remaining alternatives—“Predators”, “Prey populations”, “Carnivores”—refer to di

Ref: Fundamentals of Ecology, Odum & Barrett, 5th Ed., Ch. 4

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