Because you can consume something does not negate the need for the other. As a species we can't survive without meat - it is the primary source of development both neurologically and muscular. This has already been show in rats and in tribes in Africa. We are omnivores.

Unless someone can come up with a cogent example of how this world - and its many species would survive?

Pathetic. It's not so much the meat that makes you gain as it is the potatoes you eat with the steak. Vegans can be fat - I've seen them fat from eating tons of starchy food.

No - simply put humans can't survive as a species over time without meat. It is a critical source for our species in both brain and muscular development. There has already been 2 studies on tribes in Africa (low intelligence and muscular deformity) and in labs on rodents showing fetal retardation and severe muscular deformities and etc in generations. Can x survive without meat? Surely so. They've already benefited from meat consumption in early life or via their mother ... However if this went on generations = fetal retardation and etc would follow. Not to mention the devastation that would follow in the path in loss of habitation for numerous animals from displacement, insects and so ... all crucial to the chain of life. Humans are so narcissistic that they truly believe themselves - over millions of years of evolution ... know better than nature itself of what makes a species survive.

This is why I tune silly vegans out.