Statement 1: In a food chain number of organisms at each successive level decreases.
Statement 2: Number of organisms at any trophic level depends upon the availability of food and energy.
Each food chain consists of producers, herbivores, primary carnivores and so on. Each step of the food chain is called as the trophic level. Number of organisms at any trophic level depends upon the amount of food and energy at the previous level. Therefore most food chains will have higher number of organisms at the producer level and the number decreases at each successive level. In grassland ecosystem, the maximum numbers of organisms are found in the lower trophic level. But there are exceptions to this, in a tree ecosystem or a parasitic food chain although the number of organism at the first trophic level- the tree or the host respectively is just one, the number of organisms at the successive levels increases, the animals living on the tree and the parasites on the host body. Therefore statement 1 is not always true.