AP Bio Study Guide

Big Idea 2.A

What is the difference between an autotroph and a heterotroph?

Autotrophs manufacture their own organic molecules. For example, photoautotrophs (using light energy) and chemoautotrophs (using inorganic substances).

Heterotrophs obtain energy by consuming other organic substances. For example, animals, parasites (live off of their hosts), and decomposers (obtain energy from decaying matter).