What would happen if microorganisms did not exist in the world?

Answer 1

Life would cease to exist. Even though some of these tiny living things can cause chaos to humans, animals and plants (agriculture), they also perform many necessary functions that are part of the cycle of life. Such as, when a human, plant or animal dies bacteria break it down into a form that becomes fertilizer (food) for plants. We and animals eat these plants. We and other animals eat the animals that eat the plants. Thus the cycle continues. There are many other examples of important things microorganisms do, this is just one.

Answer 2

Bacteria are a crucial part of the biosphere and the physiology of most higher organisms. To put it simply without bacteria you and all life as we know it would not exist.

For example bacteria such as Cyanobacteria are nitrogen-fixers responsible for turning nitrogen gas abundant in the atmosphere but biologically unusable into usable nitrogen in an organic form as amino-acids. Nitrogen is the limiting nutrient in most biospheres and bacteria are the only source of new nitrogen to replace nitrogen lost from the nitrogen cycle into the environnement. Nitrogen is needed to form amino-acids which form proteins which are a huge part (both in significance and by weight) of any living organism.

Cyanobacteria is also of note because it is extremely widespread responsible for 20-30% of the photosynthetic activity on the planet (comparable to the rainforests or zoo-plankton blooms in magnitude). Many other bacteria photosynthesize but Cyanobacteria are by far the most widespread. Photosynthesis is the only way for energy to enter the biosphere (from the sun) and is obviously very important to life for that reason.

The above are two of the ways that bacteria are crucial for life as we know it but there are certainly more.

Your body is home to a huge range of symbiotic (and non-symbiotic but non-harmful ones) bacteria that make up the so called 'human microbiome'. In terms of cell number these outnumber your own cells by 10 to 1 and this is the case for most if not all higher organisms. Without these symbionts you could not for example properly digest much of the food you eat properly, they also play a role in defense against pathogenic species, and probably many, many, many other roles that have not yet been discovered. Without them you or any higher organism could not survive.

Answer 3

The earth would be in bad shape because there are many good kinds of bacteria that we need to survive

Answer 4

There would be no life :p