Final answer:
An ecological pyramid is a graphical representation of trophic levels in terms of organism numbers, biomass, or energy content.
Step-by-step explanation:
An ecological pyramid is a graphical representation of the different trophic levels in an ecosystem, displayed in terms of organism numbers, biomass, or energy content.
The base of the pyramid consists of primary producers, which are usually the most abundant and possess the highest amount of energy at 1,000,000 kilocalories.
Energy pyramids are always upright because energy, as it moves through the trophic levels from producers to primary consumers then to secondary consumers and so on, is lost primarily through metabolic processes and heat.
Only about 10% of the energy is passed on to the next level.
Therefore, it is impossible to have an inverted energy pyramid in natural ecosystems.
In terms of biomass, some ecosystems can have inverted or diamond-shaped pyramids.
This occurs when the turnover rate of the primary producers, such as phytoplankton, is very high, so they are consumed rapidly but reproduce quickly enough to support the rest of the ecosystem.
This swift turnover minimizes their biomass at any given time, even though they are tremendously productive.
For example, the biomass pyramid from the English Channel ecosystem is inverted due to the high turnover rate of phytoplankton.
Finally, addressing the possible construction of a pyramid with more biomass of carnivores than herbivores, this is theoretically atypical in nature because energy loss at each trophic level, through respiration and other biological functions, constrains the biomass at higher levels.
Usually, there's less biomass as you move up the trophic levels, because each level sustains fewer organisms due to the energy lost.