Why does a mouse not die in a sealed container if a live plant is present inside? - briefly
The plant carries out photosynthesis, converting the mouse’s exhaled carbon dioxide into oxygen and thereby sustaining a breathable atmosphere. The mouse consumes this oxygen, creating a closed‑loop gas exchange that prevents fatal depletion.
Why does a mouse not die in a sealed container if a live plant is present inside? - in detail
A rodent placed in an airtight enclosure can survive when a green organism capable of photosynthesis is also present. The plant converts carbon dioxide released by the animal into oxygen, maintaining a breathable atmosphere. This exchange depends on several factors.
Oxygen supply is sustained if the photosynthetic rate exceeds the animal’s respiratory consumption. The rate is determined by light intensity, leaf surface area, and the plant’s health. Sufficient illumination—natural or artificial—allows the plant to produce enough O₂ to offset the mouse’s demand, which averages about 0.1 L O₂ per hour for a small adult.
Carbon dioxide removal follows the same principle. The mouse exhalates roughly 0.08 L CO₂ per hour. Photosynthesis absorbs CO₂ in a roughly 1:1 molar ratio with O₂ production, keeping the internal CO₂ concentration below toxic levels. Continuous gas exchange prevents the buildup of CO₂ to concentrations that impair respiration.
The equilibrium can be summarized:
- Light‑driven photosynthesis → O₂ generation, CO₂ uptake.
- Animal respiration → O₂ consumption, CO₂ release.
- Net gas balance remains stable when photosynthetic output ≥ respiratory demand.
Plant respiration must also be considered. In darkness, the plant consumes O₂ and releases CO₂, temporarily reducing the net O₂ level. If the enclosure experiences prolonged darkness, the animal may exhaust the available oxygen. Therefore, a cycle of light and dark should include sufficient daylight periods to replenish the gas pool.
Water availability influences photosynthetic efficiency. Adequate moisture ensures stomatal opening, allowing gas exchange. Excessive humidity can limit diffusion, while severe dehydration halts photosynthesis, removing the protective effect.
The size of the container matters. A larger volume provides a greater buffer of gases, reducing the impact of short‑term imbalances. In a small sealed space, even minor deviations in light or plant health can quickly lead to hypoxia or hypercapnia.
In practice, an enclosure containing a well‑lit, healthy plant with enough leaf area, adequate water, and periodic light exposure can keep a mouse alive indefinitely, provided the seal remains intact and external temperature stays within the species’ tolerance range.