The Missing Planimal

DU — Thu, 02 Oct 2008 06:45:18 -0800

Why are there no species that implement both halves of the photosynthesis/respiration cycle? It seems like it would be handy for an animal to have a photosynthetic capability, either naturally or as a symbiont. You wouldn't have to find food or stop to eliminate waste (as often), improving workplace productivity. Your exhalations, if you still had any, would be closer to the ambient air mixture, making detection harder for those species that do that (I'm looking at you, mosquitoes).

You could also imagine it evolving from the plant end of the spectrum. In fact, it would be easier, since plants already do both halves of the cycle but the respiration half is muted and part time. Why don't they go whole hog and get double the advantage? (One could argue that plants don't use a lot of energy, so why do it, but that seems backwards to me. If they have the energy available, wouldn't a species that DID do something with it prosper?)

It seems like there are so many advantages and yet it hasn't evolved even a single time higher than lichen. Why not? The only thing I can think of is that having the advantages of both means having the disadvantages of both. But there's no disadvantage to being able, but not required, to photosynthesize. You don't have to stand still or have leaves. Just have some chloroplasts in your skin (also protects you from UV!) and if you happen to be standing in the sun, use them.

Is breathing a weight-loss program?

Camofrog — Thu, 21 Feb 2008 09:57:29 -0800

Do we lose weight just by breathing? Since we breathe in O2 and breathe off CO2, it seems to me that we are losing carbon atoms like mad each time we breathe out. This assumes, of course, that for each O2 breathed in a CO2 is breathed out, a straight one-to-one exchange, and that's a huge assumption. Is it correct?

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The Missing Planimal

Is breathing a weight-loss program?