• Primary Productivity: It's like a sunbathing session for plants! This is all about how much solar energy the plants soak up that might be lost from an ecosystem before it adds up to the total 'weight' or biomass of plant munchers (herbivores).
• Chemical Energy: This is the energy that gets respired by vegetation. Imagine the plants saying "Ahhh, time for a deep breath!" and releasing some energy. Also, there's some energy which no one nibbles on or harvests. This untouched energy becomes a snack for decomposers when the plant kicks the bucket.
• Biomass: This is the stuff that herbivores eat, but not all of it is absorbed by them. Some of it is lost in, well, 'toilet business' (faeces). Also, even after absorption, some biomass is lost through respiration. "In with the good energy, out with the bad," says the herbivore.
• Gross Primary Productivity (GPP): This is the big jackpot! It's the total chemical energy produced by a plant. But remember, some of this energy is lost due to the plant's respiration.
• Net Primary Productivity (NPP): Now we're talking net gains! This is the total productivity after taking away the energy lost through respiration (i.e., GPP - respiration). It's like the plant's 'take-home pay' after all the expenses are paid off. This is the energy that gets converted to new biomass and is up for grabs for the next level of the food chain (trophic level).

Consider a lush green forest. The trees, with their vast spread of leaves, are bathing in sunlight and cooking up a chemical feast through photosynthesis. This is the Gross Primary Productivity (GPP). But, like a tax on this feast, some energy is used for their own 'life processes' or respiration.

Now, the leftover energy or the 'take-home pay' for the trees, the Net Primary Productivity (NPP), is the buffet spread for the herbivores like deer, rabbits, etc. But remember, not all the energy is efficiently used. Some of it is lost through their digestive system (poop!) or through their respiration.