"if it had happened twice the newcomer would have been called 'food' at a stage too early to get much further up the ladder"

I'm sorry, but this doesn't make any sense. Just being called "food" is not a sufficient reason for extinction. In fact, organisms at the bottom of the food chain constitute the majority of biomass in all known ecosystems.

Right. I think the argument was more along the lines of the Niche Exclusion Principle[1]. Once the existing complex organisms have had time to adapt "perfectly" and fill "all" of the low-level ecological niches, the barrier to entry becomes dramatically higher. The odds of evolving complexity were already abysmal. The presence of an additional barrier makes it almost impossible, since the new, unoptimized design would have to compete with the established species.

It's a debatable argument, with obvious parallels in the startup world.

[1] http://en.wikipedia.org/wiki/Competitive_exclusion_principle

In ecology, the competitive exclusion principle is a proposition which states that two species competing for the same resources cannot coexist if other ecological factors are constant. When one species has even the slightest advantage or edge over another, then the one with the advantage will dominate in the long term. One of the two competitors will always overcome the other, leading to either the extinction of this competitor or an evolutionary or behavioral shift towards a different ecological niche. The principle has been paraphrased into the maxim "complete competitors cannot coexist".

This talks specifically about those higher up in the food chain, that's what the 'complex' is all about.

No, by 'complex' it's talking about non-single-celled organisms. The article specifically mentions all animals, plants and fungi. In Biological terms, grass is a complex organism.

So, let's take the minimal case of 'complex' a system of two cells vs a system of only one cell.

Any animal from the 'other' branch that observes this 'complex' life from made of two cells and another one nearby made of only one would have the choice between two bites for the price of one and one bite.

So new 'complex' life would not be around for very long because the ohter branch has presumably already reached a higher level of evolution.

It would have be a very successful mutation to stick around long enough to have enough offspring to take on higher organisms than itself by having some survive in spite of being predated on.

The lowest level organisms best defense against extinction is their enormous numbers or symbiotic relationships by evolving in tandem with higher order forms, a brand new attempt at complexity would not have that advantage yet.

The same goes for another carbon based evolution scenario, after all, if there could be two independent complex branches of life it would not be too much of a stretch to think that over the last billions of years a second life form would have come in to existence. But it would have found each and every niche already occupied by 'our' kind of life and likely not survive long, and likely not leave any trace of its existence.

More than that, in biological terms yeast is a complex organism.

Was it John Maynard Smith - The Major Transitions in Evolution? It's a great book, that goes deeper than Dawkins' vulgarizations.

I wouldn't call any of Dawkins' work a 'vulgarization'.

Uh, yeah, I was wondering if that word was appropriate in English. I meant it in the sense of:

to make (a technical or abstruse work) easier to understand and more widely known; popularize. (from dictionary.com)

Yes, as you have learned through this thread, only very learned persons say "vulgarization" in English to mean "popularization," so it's safest in Internet writing simply to write "popularization."

Well, learned, or people who speak French: http://fr.wiktionary.org/wiki/vulgariser

EDIT: I see that someone beat me to the punch ...

Unless, of course, your primary goal is to be pretentious, in which case go ahead and use "vulgarisation".

Vulgar has a very negative connotation to it. The main thing I associate with "vulgar" would be swearing, crassness, or uncouth behavior. I haven't seen the word vulgarization used really, but it inherits that contexts from its root word to me.

Likewise in French! But we still use the word "vulgarisation" to describe popular science books, in a good way.

Yes, though you can also be non-edible by being out of the way.

Arm-chair surmisingly best, may be. Scientifically, not.

In fact, healthier ecosystems promote prey more than predators.