summary 3 Food Chains and Food Webs

The changes in a population can affect several other population in the same ecosystem. Every population needs energy in order to survive. 
A food chain shows one population that eats or is eaten by another population. A food web shows how one population can be part of more than one food chain. Both have producers that includes grasses, trees, and all the organisms uses Sun's energy to make their own food. In the ocean main producers are the algae. The organism that can't make their own food are called consumers. The consumers get energy from the food made by others oraganisms. Plants capture energy from the sunlight. When you eat a plant you capture some energy. The producers get enrgy from the Sun. Consumers get it from the food they eat.
An energy pyramid shows that less food and energy is available as you go from the base to the top of the pyramid.
People is affected by red tide. A person who eats poisoned shellfish can become very sick. The poisons produced by fire algae seem to onlyaffect the nervous systems of complex animals like fish, birds, and mammals
                                          Food Web