Originally Posted By: ImagingGeek

So calling any organism "higher" or "lower" is naive at best - we've all run the gauntlet of evolution for the same length of time, and all been successful at it. The only difference between "higher" and "lower" is the number of cells we happened to end up with.

Again you are missing my argument .. it will be clarified when I discuss you answer to my last question.

Originally Posted By: ImagingGeek

The plasciticty that evolved early in lifes development is the very key to its success.

Again I will pick this up because I agree it's important.

Originally Posted By: ImagingGeek

Sorry, but that is completely backwards. Selection forces on bacterium are far stronger than that observed in multicellular organisms - indeed, the rates of genetic change, speciation & extinction are orders of magnitude higher in single celled organisms; a clear sign of stronger evolutionary impacts measured over the same period of time. To put it into context, your average bacterial species lasts from tens of thousands to a few hundreds of thousands of years; your average metazoan (animal) species lasts from 2-3 million (mammals) to 16-25 million years (formernera).

I don't buy that they are stronger on the bacterium at all I believe they have less mechanisms with which to adjust to enviroment changes or competition ... hence they die out as a species faster. If you go forward to humans we can even control our enviroment to a high degree.

This was what I was getting at a complex organism has more things to attack and normal science entropy logic says it should be weaker BUT IT ISN'T that means something is important going on here .. so you missed my point.

You need to look at how a complex thing can be more robust than a simple thing because in the real world they never are unless they are engineered ... and no I don't believe in inteligent design smile

Originally Posted By: ImagingGeek

The first thing to keep in mind is the vast majority of organisms - whether measured as total number of individuals, total number of species, or total biomass - are single-celled organisms (on a scale of 100:1 to trillions:1, depending on your choice of measurement). Meaning that multicellularity, as a survival mechanism, is not overly successful. The question isn't so much why it came about, but rather why it is such a rare evolutionary path.

I would have thought that it is obvious why it is rare go back to all your own comments above.

Originally Posted By: ImagingGeek

In terms of why it arose, predation is thought to be the primary driver - unicellular predators like amoebas cannot eat things larger than a few cells in size, so a simple multicellular organism like a sponge, or a pseudo-multicellular organism like choanoflagellates, can avoid a strong selective force simply by "clumping". After that, in-clade competition (i.e. competition between multicellular organisms) appears to have driven much of the rest of the evolutionary processes. Indeed, if you look at most of what has happened since we became multicellular, most of the adaptations have been to compete against other multicellulars.

And I totally agree with the above which when you put your own answers together it tells you why the complex organisms are considered advanced or higher.

Using your own logic statements my argument goes like this

- The simple organisms having only simple attack and defensive abilities could not out compete some complex organisms which developed and forced out a survival niche.

- These early simple organisms had plasticity that was the key to there success but it also put some limits on enviroment which more complex organisms could adapt to with more complex structures, behaviours etc.

- Ultimately more complex organisms tend to survive as a species longer because they have more ways to solve the survival issues.

All of that defines complex organisms as being more advanced because they forced there way into survival against all the odds and now survive longer as a species than simple organisms.

If you take this back to simple cars a Model T ford and the latest ferrari are equally successful they both exist today but trying to deny the Ferrari is not more advanced than the Model T is denying the obvious.

Last edited by Orac; 02/26/13 04:31 PM.

I believe in "Evil, Bad, Ungodly fantasy science and maths", so I am undoubtedly wrong to you.