An energy pyramid shows maximum energy at the base and steadily diminishing amounts at higher levels. The predominant organisms in an ecosystem are plants. Plants have the most energy available to them, because they trap it directly from sunlight. Far more people can be fed on grain than on meat. Primary consumers (herbivores) that feed on plants store less energy. Secondary consumers that feed on the primary consumers store even less energy and tertiary consumers (usually carnivores) store even less. Decomposers liberate nutrients for reuse that return to the atmosphere, soil, and water.

The food web is a complex feeding relationship within a community including many organisms at various trophic (feeding) levels, with many of the consumers occupying more than one level simultaneously. Herbivores (plant eaters), Carnivores (meat eaters), omnivores (Latin, "eating all), detritus feeders (debris eaters) and decomposers (bactetia and fungi) are all part of the food web. A food chain illustrates who feeds on whom in a community in a linear feeding relationship. A food chain identifies a representative of each trophic level that eats the representative of the level below it. During the carbon cycle, carbon is captured from the atmosphere during photosynthesis and passed up through the trophic levels. It is released during respiration from all trophic levels and by the burning of forests and fossil fuels. The Krebs cycle is a series of reactions occurring in the mitrochondria in which ATP is formed, which is the major energy carrier in cells. An energy pyramid is a graphical representation of the energy contained in succeeding trophic levels, with maximum energy at the base and steadily diminishing amounts at higher levels.

The correct response is primary consumer. The primary consumer is any organism that eats autotrophs (photosynthetic organisms). A secondary consumer feeds on the primary consumer, and so on and so forth.

Secondary productivity is the biomass accumulation of all levels of consumers. Herbivores and Carnivores are always grouped together in terms of productivity. The productivity of plants and their biomass due to photosynthesis is Primary productivity. The total biomass of an ecosystem is the sum of Primary and Secondary productivity.

Only three of the answer choices represent actual types of food webs: connectedness, energy flow, and functional. Connectedness webs are the type of food web used to represent feeding relationships. In short, they show relationships between predators and their prey.

Biomagnification is the process whereby the tissue concentrations of a contaminant increase as it passes up the food chain through multiple trophic levels. The contaminant is accumulated as it ascends the ecological food chain by transfer of residues from the diet into body tissues (sometimes referred to as 'bioaccumulation').

The ascension of toxic compounds through the food chain does not depend on slow to rapid change like a threshold effect, not does it involve cooperation between organisms like synergism. Compound contamination refers to contamination of the environment itself, and carcinogenesis refers to the initial formation of cancer, not the spread of contaminants.

From one trophic level to the next, only 10% of energy is transferred. The other 90% is lost through metabolic processes, like heat. This means that for every 10,000 kcal produced by producers, a tertiary consumer (three trophic levels above) will only receive 10 kcal.

A secondary consumer is a step above the primary consumer (herbivore) on the food chain, consisting of omnivores and carnivores. A mouse that lives off plant matter and is thus a primary consumer. When a snake eats the mouse, it is the secondary consumer in the food web.

The correct response is **detritivore.**Organisms classified as detritivores break down organic matter from dead animals and leaves. Primary consumers feed on autotrophs, and secondary consumers feed on primary consumers. Carnivores primarily eat meat. While detritus does contain animal matter, it also contains plant and microbial matter that carnivores tend not to eat.

Umbrella species are very similar to a keystone species; however, an umbrella species refers to a species that indirectly protects many other species of its ecological community during conservation. Usually, umbrella species are migratory or require a large habitat.