Is it true that a food chain generally be gins with a heterotroph.?

Question

Is it true that a food chain generally be gins with a heterotroph.?

Answer 1

No, more commonly, food chains begin with an autotroph.

But this questions really highlights the fact that "food chain" is an artificial structure.  "Food web" is really a much more realistic and useful concept.

Autotrophs are the primary producers, like algae in water and grasses on land.  Next step up the food chain is the heterotroph, like the algae-eating zooplankton or a grass-eating buffalo.

But take the example of the zooplankton.  In their grazing they often eat not only algae, but also the bacteria that grow on dead or dying algae.  Such bacteria  or fungi may be the real source of their nutrition.  Some algae have thick cell walls and are hard to digest - they're much easier to eat after they've died and the bacteria have worked them over.  That is an example of a detritus food chain, which does begin with an autotroph but has decomposer organisms (heterotrophs) in the chain.