If all animals were to die, would all plants die too?

Question

Humans and many other animals are able to breathe because plants produce more oxygen than they need. I was thinking if all animals died all of a sudden, then wouldn't plants die too. Eventually they would produce too much oxygen and wouldn't have enough carbon dioxide to go through photosynthesis.

Answer 1

If all animals were to die, plants would not immediately die, but ecosystems would face dramatic disruptions, and certain plant species could eventually become extinct. Here’s why:

1. Carbon Dioxide Availability: Plants rely on carbon dioxide for photosynthesis, and animals contribute to carbon dioxide levels through respiration. If all animals disappeared, the carbon dioxide supply would decline over time, but not completely, as other natural processes, such as decomposition and volcanic activity, still release carbon dioxide. However, the balance would shift significantly.

2. Seed Dispersal and Pollination: Many plants rely on animals for pollination (e.g., bees, birds, bats) and seed dispersal (e.g., fruits eaten by mammals). Without these animals, plants dependent on such interactions would struggle to reproduce, leading to the extinction of certain species.

3. Soil Fertility: Animal dung and carcasses contribute to nutrient cycling in ecosystems. Without this input, soil fertility would decrease over time, impacting plant growth, especially in nutrient-poor environments.

4. Ecosystem Collapse: Plants and animals are part of a tightly interconnected web. Removing all animals would disrupt food webs and nutrient cycles, leading to the collapse of many ecosystems and making survival more difficult for plants that rely on these systems.

In conclusion, plants as a whole wouldn’t immediately die, but the loss of animals would drastically alter ecosystems, potentially leading to the extinction of specific plant species and a decline in overall biodiversity. This question highlights how deeply interconnected life on Earth truly is!