what will happen if there are only human beings exist on the earth and without any other animals

If humans were the only beings living on Earth and there were no other animals, several critical impacts would be felt across various aspects of life and ecosystems: 1. **Ecological Balance Disruption**: The extinction of all animal life would cause severe imbalances in ecosystems. Animals play a crucial role in pollination, seed dispersal, and controlling pests. 2. **Food Chain Collapse**: Without animals at lower levels of the food chain, many predators would face food scarcity, leading to profound ecological upheaval. 3. **Disease Transmission**: Some diseases are transmitted between animals and humans (zoonotic diseases). Eliminating animals could reduce this risk, but it might also deprive humans of disease-resistant mechanisms they have evolved due to such interactions. 4. **Agriculture and Livestock**: Animal husbandry plays a significant role in human sustenance, particularly for those who depend on livestock for milk, meat, eggs, and labor. Crops require pollinators often provided by insects and other wildlife. 5. **Biodiversity Loss**: Extensive loss of biodiversity would have irreversible impacts on natural environments, creating barren landscapes and eliminating many of the world's majestic species. 6. **Environmental Services**: Many animal species provide essential services like nutrient cycling, maintaining soil health, water filtration, and air purification. 7. **Cultural and Emotional Impact**: Animals are an integral part of many cultures worldwide and hold emotional significance for many people, providing companionship and enriching human lives. 8. **Scientific Research**: Animals have been vital subjects in medical and scientific research, contributing to breakthroughs in advancements spanning drug discovery to new technologies. 9. **Economic Consequences**: Many industries are dependent on animals directly or indirectly, from fashion to food production, and from tourism to pharmaceuticals. 10. **Long-Term Survival**: In the long run, if there were no animals left on Earth, the effects on Earth’s ability to sustain human life would become critical since multiple ecological functions would be compromised. The absence of other animals would ultimately lead to a severe diminishment of the biosphere's health, with far-reaching consequences for human survival and well-being. This scenario underscores the importance of biodiversity conservation and sustainable coexistence with other life forms on our planet.