well if you count the sun as part of a food chain then the producers are the second thing on it. However, if you think that producers are the first thing then the second would be the first order consumers. They are usually herbivores.
A food web is a series of lines coming from one animal to another with an arrow at the end. A food chain is a kind of chart with lines coming from one creature to another, again with arrows. the...
All life on Earth depends on the energy from our sun. The sun provides energy for plants and bacteria. Animals feed on those and on each other. So everything comes from the sun.