[Serious] Why defecation?

[BrianSoddingBoru4]

None of that matters. Give me a good and sufficient reason why God would design wombats to excrete 50% of what they eat when he could just as easily have designed them to metabolize 100% of what they eat.

Boru

This demand just seems very poorly formulated. You've narrowed down on a number without any understanding as to why it occurs; and treat 50% as wrong solely because it isn't 100%. I disagree with that.

Food is only needed to meet the metabolic needs of a given animal; and animals are free to eat whatever they want. The only issue I would have with a digestive system excreting 50% of food is if the metabolic needs of the organism are not being met with this number. In this scenario the animal is starving despite eating sufficient food.

I’m not saying it’s ‘wrong’, I’m saying it’s not maximally efficient. ‘Why would God create this system when he could have created something better?’ is a question you seem intent on dodging. Or maybe I’m putting it badly. I’ll try again.

Imagine a world where all organisms are able to meet their metabolic requirements without waste. Everything the wombat eats is turned into energy - protein, sugars, fibrous cellulose, etc.  Isn’t that more efficient (not ‘right’, not ‘wrong’) than the wombat having to consume twice as much and excrete half of it? Since the wombat is going to consume fibrous cellulose in any case, wouldn’t it make sense for the animal to have been so designed as to make use of it in some way?

Boru

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reply to your edit: I don’t think that would be the case at all. As I just described, a wombat with 100% digestive efficiency would have more metabolic headroom, not less.