Evolution in action?

In response to the cAMP distress call, up to one hundred thousand of the amoebas assemble. They first form a tower, which eventually topples over into an oblong blob about two millimeters long. The identical amoebas within this pseudoplasmodium– or slug– begin to differentiate and take on specialized roles.

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Once their food source is depleted, these single celled animals coalesce into a multicellular entity, which even includes an immunity system

The slug begins to seek out light, leaving a slimy trail behind. Some of the amoebas take on the difficult role of sentinel, or immune-like functions. They circulate through the slug, hunting for pathogens. If they find any, they will engulf them in a process similar to the feeding behavior they once displayed when in solitary form. The pseudoplasmodium periodically sloughs off the sentinels– and any pathogens they have engulfed– and abandons them in the trail of slime. More cells will then be tapped to fill their place.

The beginnings of a complex body of cells working collectively towards a common cause. Is this evolution in action?

reply to post by shanti23


Interesting, then could you please explain the steps for the selection of epithelial cells? For example cuboidal epithelia in the kidney, skin epithelia, endothelial cells around capillaries, ciliated epithelia in the trachea......

Yes you have an interesting model but there are too many steps missed out at present to make such a big claim.

Hi Heronumber0, thank you for your reply.

It wasn't a claim as such, you have misunderstood my post; that is why I placed a question mark after the title: Evolution in action?

I would preferably not make such a bold assumption as to know how the universe is structured.

However, it is interesting to see individual cellular animals assuming the separate and specialized tasks required for a multicellular entity.

Especially the way some amoebas assume the role of an immune system for the 'body'. Logic would assume they do this from necessity.

The question then is, how the hell do they know to do that?

Originally posted by shanti23
The question then is, how the hell do they know to do that?

I'm gonna go with MAGIC, jk its prolly basic instinct. Thats really interesting though, the whole ditch the disease idea is genius though, I doubt it would work in a large being like humans though

Welcome Damien.

Originally posted by Damien_Hell
I doubt it would work in a large being like humans though

That is exactly how neutrophil cells work in the human body. They fight invaders by 'eating' the bacteria or other foreign matter. The neutrophil membrane wraps around the invader, which it then effectively digests using enzymes. This process is known as phagocytosis.

So the amoebas that are performing this task inside the collective are demonstrating the early stages of this behavior.

Perhaps with time and environmental necessity, this collective 'organism' would evolve to be more complex.