Your previous question asked-- what would occur to Earth's atmosphere if all the producers were to disappear? This next question relates to how animal life would be affected by this atmospheric change. The atmosphere would be high in carbon dioxide levels due to producers no longer using it in carbon fixation to produce sugars during the light independent reaction of photosynthesis. Also, as animals carried out cellular respiration to get energy to live, they would be adding to the carbon dioxide levels every time they exhaled. Carbon dioxide and water vapor are released as wastes as a result of aerobic respiration. If producers were no longer on Earth, the oxygen gas they normally release during photosynthesis would no longer be added to the atmosphere. This oxygen is formed when water is split into hydrogen and oxygen gas during the light reaction of photosynthesis, in a process called photolysis. This would mean death to all the aerobic organisms on Earth, when the oxygen supply eventually would run out.