Question

What is a trophic level? An ecological pyramid? (pages \(547-48\) )

Short answer

A trophic level is the position an organism occupies in a food chain, representing the steps of energy transfer within an ecosystem. An ecological pyramid is a graphical representation of the distribution of energy, biomass, or numbers of organisms in an ecosystem across different trophic levels. For example, in a food chain such as grass → grasshopper → frog → snake → hawk, the trophic levels would be organized in a pyramid shape, with the most energy, biomass, or number of organisms at the base (grass) and decreasing amounts as one goes up the pyramid to higher trophic levels.

Step-by-step solution

Definition of Trophic Level

A trophic level refers to the position an organism occupies in a food chain. It represents the steps of energy transfer within an ecosystem. Each trophic level is made up of organisms that share the same function in the food chain, and it indicates the number of energy transfer steps away from the energy source (usually the sun).

Example of Trophic Levels

For example, in a food chain such as grass → grasshopper → frog → snake → hawk, the trophic levels would be: 1. Grass (producer) 2. Grasshopper (primary consumer) 3. Frog (secondary consumer) 4. Snake (tertiary consumer) 5. Hawk (quaternary consumer)

Definition of Ecological Pyramid

An ecological pyramid is a graphical representation of the distribution of energy, biomass, or numbers of organisms in an ecosystem across different trophic levels. It helps us visualize the energy flow, biomass distribution, or population sizes in food chains and food webs. There are three main types of ecological pyramids: 1. Pyramid of energy: Represents the flow of energy from one trophic level to the next. 2. Pyramid of biomass: Represents the total biomass (weight of living organisms) present in each trophic level. 3. Pyramid of numbers: Represents the number of organisms at each trophic level.

Example of Ecological Pyramid

For example, in the previously mentioned food chain (grass → grasshopper → frog → snake → hawk), an ecological pyramid would illustrate the distribution of energy, biomass, or numbers of organisms in the ecosystem. The pyramid would look like this: ``` Hawk / \ Snake Frog / / \ Grasshopper Grass ``` With each level in the pyramid representing a trophic level. In a pyramid of energy, the base (grass) would have the most energy, with decreasing amounts of energy as one goes up the pyramid to higher trophic levels. Similarly, in a pyramid of biomass, the base would have the greatest biomass, and the pyramid of numbers would have the largest number of organisms at the base.