UCSB Science Line
Sponge Spicules Nerve Cells Galaxy Abalone Shell Nickel Succinate X-ray Lens Lupine
UCSB Science Line
How it Works
Ask a Question
Search Topics
Our Scientists
Science Links
Contact Information
I know that plants take in carbon dioxide and give out oxygen. But do all plants need oxygen? What if all the plants where gone what will happen to the presence of the humans? Will we all die slowly? What will happen to the animals?
Question Date: 2013-11-19
Answer 1:

Plants need oxygen when they're not photosynthesizing (e.g. at night).

There are other life-forms capable of photosynthesis and producing oxygen, including many forms of algae and some bacteria. However, if all photosynthetic life were to become extinct, then animals (including humans) would die out as well, yes.

Answer 2:

You are absolutely correct, plants definitely need oxygen just like most other organisms. Plants generally have a net uptake of CO2 compared to O2. The plant uses this carbon to create sugars (for energy) and construct plant tissue (for structure, this is how plants grow). Oxygen is used to break apart the sugars and release energy when needed. If all plants were gone (let's say that this means all photosynthetic organisms including bacteria), then yes, we would all suffocate from lack of oxygen as it would get used up by all of the organisms left on earth. Nothing would survive, but I don't foresee this happening as there are many, many different organisms that photosynthesize and release oxygen into the atmosphere. Here is the history of Oxygen build-up in our atmosphere:

click here to read about

Click Here to return to the search form.

University of California, Santa Barbara Materials Research Laboratory National Science Foundation
This program is co-sponsored by the National Science Foundation and UCSB School-University Partnerships
Copyright © 2020 The Regents of the University of California,
All Rights Reserved.
UCSB Terms of Use