Observation designed to minimize the effects of variables other than the independent variable.
The producers are the main source of the food production in the ecosystem. The producers are the organism, which convert the energy from the sunlight into the chemical energy. The consumers use this chemical energy for carrying out the metabolic processes in their body.
Without producers, the consumers cannot obtain their energy. Hence, the ecosystem without any producer would not survive.
...that seemed to reflect the size of seeds the birds ate.
