what will happen if the earth is only inhabitated by humans

If the Earth were to be inhabited solely by humans, without any other living organisms (plants, animals, and microorganisms), it would result in a tremendous impact on the planet's ecosystems and human survival itself. Here are some of the potential consequences:

1. Collapse of Food Chains: The extinction of other species would disrupt food chains, as humans would lose sources of food and essential nutrients. Agriculture would collapse without pollinators like bees, and without plants, the entire food web would be severely affected.

2. Loss of Biodiversity: Biodiversity is crucial for maintaining the health of ecosystems. The loss of it would lead to the collapse of various ecological systems which in turn could lead to the extinction of human life.

3. Disease and Health Issues: Many medicines and treatments come from other organisms. Without them, humans might lose access to important medicines and face increased risks from diseases that currently have natural controls or treatments.

4. Decomposition and Waste Management: Decomposition of organic matter is carried out by microorganisms and certain animals. Without them, waste would accumulate, leading to severe environmental pollution and public health crises.

5. Climate Change: Plants play a critical role in absorbing carbon dioxide and producing oxygen. Without plants, the balance of gases in the atmosphere would quickly become unmanageable, exacerbating climate change and leading to extreme weather conditions.

6. Soil Erosion: Without plant roots to anchor soil and help prevent erosion, soil quality would rapidly decline, leading to desertification and the loss of fertile land.

7. Water Cycle Disruption: Plants help maintain the water cycle by absorbing water through their roots and releasing moisture into the atmosphere through transpiration. This process would cease, leading to significant changes in precipitation patterns and water availability.

8. Economic Implications: Many industries rely directly or indirectly on biodiversity, such as fisheries, forestry, pharmaceuticals, and tourism. The economic impact would be profound, potentially leading to widespread unemployment and economic collapse.

9. Psychological Impact: The loss of other life forms could result in significant psychological stress and a sense of isolation, potentially leading to a decline in overall human well-being.

In essence, humans and the rest of Earth's biodiversity are interdependent. A world with only humans would be a stark and unsustainable environment, highlighting the importance of conservation and the protection of biodiversity for the survival and prosperity of all life on Earth.