This is a very random question, but it has been bothering me for a while... Can you please help me?

Different forms of life have evolved to obtain the energy they need to stay alive in different ways. Plants and animals (including humans) obtain their energy in different ways; plants through the process of photosynthesis and animals through the process of cellular respiration. But plants and animals have an undeniable symbolic relationship. Why would humans (as consumers) cease to exist without plants (as producers) on our planet? Can you please please answer the question by comparing the 2 chemical reactions of photosynthesis and cellular respiration.