Where do herbivore animals get their protein from?

[ElectricFetus]

The only significant quantity of amino acids in plant tissue are in the seeds, which comprise a tiny portion of the plant, as well as being (usually) seasonal. Herbivores are not getting a useful amount of nitrogen directly from the plants.

Do you have evidence for this? I ask you cite evidence the they could not extract enough amines and nitrogen containing compounds from plant matter alone.

It has to be the bacteria that are doing this, so the question remains: Where do they get the nitrogen?

There is no evidence that nitrogen fixation occurs at levels capable of sustaining ruminants:
http://journalofanimalscience.org/content/41/4/1161.full.pdf+html

So they have to be getting all their nitrogen from compounds in the plants, not gut flora, which at best process, convert and release these compounds from the plant matter.

That's not what I've read. It's the maintenance and operation of the brain that accounts for a large portion of our protein intake.

No please cite evidence of the amount of daily protein uptake the brain requires.

Ancestral hominid species became obligate carnivores when their brains grew too large for the typical primate's herbivorous diet augmented by occasional arthropods and other tiny animals. Fortunately the larger brain gave them the ability to invent the hunting tools needed by an obligate carnivore with no fangs or claws.

This is circumstantial, it is not evidence that brains require a lot of protein for simple maintenance.

The most striking anatomical change in dogs, as they evolved into a distinct subspecies of wolf, is the shrinkage of the brain to accommodate the lower-protein diet of a scavenger.

Again proof of nothing only correlation.

 

[billvon]

Cellulose can't be converted to protein anymore then lead can be converted to gold: Nitrogen must be coming from somewhere and cellulose (with the exception of hemicellulose) has no nitrogen in it what so ever.

Cellulose doesn't, but plants have a lot more than cellulose in them. For example, they synthesize glutamate which contains bioavailable nitrogen. Also keep in mind that mammals can synthesize most of the amino acids they need.

 

[ElectricFetus]

Cellulose doesn't, but plants have a lot more than cellulose in them. For example, they synthesize glutamate which contains bioavailable nitrogen. Also keep in mind that mammals can synthesize most of the amino acids they need.

I think I stated enough sources of nitrogen in plants, rather mammals nor plants can synthesize amines themselves: they can't fix nitrogen but need nitrogen compounds to make proteins, only specific bacteria can fix nitrogen and that is where ALL of the nitrogen in protein fundementally comes from.