Primary consumers, also called herbivores, are very important in how energy moves through ecosystems. They connect plants, known as producers, with animals that eat them, like carnivores and omnivores. Let’s break down their role in a simple way:

1. Energy Transfer:

   • Plants take in sunlight and change it into energy, turning about 1-2% of that energy into food for themselves through a process called photosynthesis.
   • Primary consumers, like rabbits or cows, take in energy from plants. They turn about 10-20% of the energy they eat into their own body. This fits with the idea that only about 10% of energy moves up the food chain.

2. Food Webs:

   • Primary consumers are the second level in food webs because they eat plants (which are called autotrophs).
   • They play a key part in food webs, giving energy and nutrients to animals that eat them, which are called secondary consumers.

3. Biomass and Animal Numbers:

   • In land ecosystems, primary consumers can make up about 15-30% of the total weight of living things (biomass).
   • For example, in the African savannah, the weight of herbivores can be as high as 250 kg for every hectare (a measure of land).

4. Nutrient Recycling:

   • Primary consumers help recycle nutrients. When they eat plants, their waste helps break down plant material, putting nutrients back into the soil.

5. Effect on Plants:

   • When herbivores eat too many plants, it can change which plants grow in an area. This affects the variety of plants and can change how stable the ecosystem is.

In these ways, primary consumers are essential for helping ecosystems work properly and for making sure energy flows through different levels of the food chain.