Energy flow in an ecosystem is ___ and ___ through the trophic levels.

Unidirectional and involves loss of energy as heat

In a grazing food chain, the primary consumers are typically ___ and ___.

Herbivores and depend on plants for food

True or False: The pyramid of biomass is always upright in aquatic ecosystems.

False; it can be inverted in aquatic ecosystems.

What are the two main processes involved in the movement of pollutants through trophic levels?

Bioaccumulation and biomagnification

In the nitrogen cycle, nitrogen must be ___ before it can be utilized by plants.

Fixed into ammonia, nitrites, or nitrates

What distinguishes primary succession from secondary succession?

Primary succession starts on bare ground.

• Begins with bare substrate.

• No soil initially present.

• Occurs over a long time.

True or False: The carbon cycle involves the direct uptake of carbon dioxide by animals.

False; animals obtain carbon through consumption of plants or other animals.

The sulphur cycle primarily operates through which type of cycle?

Sedimentary cycle with a gaseous component