5.2.1.4.1.1. Terrestrial Ecosystems

•They show the relationship between producers, herbivores, and carnivores at successive trophic levels in terms of their number. •In case of pond ecosystem the producers are mainly phytoplankton and are always maximum in number this number then shows a decrease towards apex as primary consumers are zooplanktons are lesser in number than phytoplankton, the secondary consumers are large fish are even lesser in number than the phytoplankton. Thus the shape of pyramid is upright. But in case of forest ecosystem the pyramids is always inverted because the producers are mainly large trees, are lesser in numbers, the herbivores fruit eating birds are more in number than the producers, then there is gradual decrease in number of secondary consumers thus making pyramid upright again. Thus the pyramid of number does not give a true picture of the food chain and are not very functional.

The Pyramid of Number illustrates the number of organisms at various trophic levels in an ecosystem. In a pond ecosystem, there are many producers (like phytoplankton), which means there are more phytoplankton than herbivores (like zooplankton), and even fewer secondary consumers (like larger fish). As a result, the pyramid is upright because there are more organisms at the base than at the top. Conversely, in a forest ecosystem, the base consists of fewer producers (large trees), while there are more herbivores (like fruit-eating birds) than producers. This leads to a shape that can appear inverted. Thus, this model does not accurately reflect food chains because it doesn't consider the biomass or energy found at each level.

Imagine a classroom. If there are 30 students in a grade (like phytoplankton), a few student helpers (like zooplankton), and just a couple of teachers (like fish), the classroom is filled at the start and slowly empties out. This creates a situation where the most students are at the bottom (the base) and far fewer teachers at the top (the apex). In contrast, if you look at a smaller class where there are fewer students but more assistants, it turns the pyramid upside down, showing that sometimes there can be more help than students!

•The pyramid of biomass represents the relationship between different trophic levels in terms of biomass. •There is generally gradual decrease in biomass of organisms at successive levels from the producers to the top carnivores. Thus pyramid of biomass is upright for grassland ecosystem. •However in case of a pond as the producers are algae, are least in number and this value gradually shows an increase towards the apex of pyramid thus making the pyramid inverted in shape.

The Pyramid of Biomass focuses on the total mass of organisms at each trophic level, rather than their numbers. In a grassland ecosystem, there is a decrease in biomass as we move from producers to carnivores, leading to an upright pyramid. However, in a pond ecosystem, there are few producers (like algae) which have low biomass. As we move up to higher trophic levels, the biomass can actually increase, resulting in an inverted pyramid shape. This highlights how different ecosystems can function differently based on the types and quantities of organisms present.

Think of a bakery. At the start, you have a large bulk of flour and sugar (the producers), which gets used up in baking. As you bake, you create bread (primary consumers) which is less in total weight than the initial ingredients but still sustains more consumers like butter and jam that are used to enhance the bread (secondary consumers). In a pond, the algae are like leftover flour - less in bulk, while the ‘tasty’ bread (or fish) that results from it might weigh more when compared on a larger scale.

•Of the 3 types of ecological pyramid the energy pyramid gives the best picture of overall nature of the ecosystem. In this type of pyramid the trophic level is decided depending upon the rate at which food is being produced. •In shape it is always upright as in most of the cases there is always gradual decrease in the energy content at successive trophic levels from producers to various consumers.

The Pyramid of Energy presents the flow of energy through an ecosystem, offering a clearer view of ecosystem functions compared to the previous pyramids. This pyramid is always upright, as energy typically decreases at each successive trophic level due to energy loss in metabolic processes, heat, and other natural factors. Consequently, producers have the highest energy content, while it diminishes as it moves up to consumers, illustrating the inefficiency of energy transfer within ecosystems.

Imagine a long chain of runners in a relay race. The first runner (the producers) starts off with a full tank of energy. As they pass the baton to the next runner (primary consumers), they lose some of that energy from fatigue. Continuing the baton pass, each runner has less energy available for the next, showing how energy diminishes through each stage of the race and highlighting the importance of the initial energy source.

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