Evolution of single celled organisms

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  • #26
damgo
You know, I haven't seen any valleys carved out by glaciers recently. Or fertile islands rising out of the sea by volcanic eruption. Those theories must be bunk too!

Those volcanic islands that get bigger from eruptions, well that's micro-volcanic-island-formation, not macro-volcanic-island-formation. Volcanic-island-formationists are just deluding themselves because they can't let themselves believe the clear fact that God created all those islands fully formed!
 
  • #27
I guess the answer is "no".

I guess a simple "no" would have sufficed. :smile:
 
  • #28
damgo
^^^ Why don't you define criteria for exactly what you mean by 'evolution,' if the examples above do not suffice? There are examples of speciation, as well as examples of dramatic phenotypic change -- compare a Dalmation, Chihuahua, and a wolf, for example.

If you expect to see a big evolutionary change that takes ~1,000,000 years done within the last 100 or so, it's obviously not gonna happen...
 
  • #29
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M.E. Boraas, D.B. Seale, and J.E. Boxhorn. (1998) "Phagotrophy by a flagellate selects for colonial prey: A possible origin of multicellularity." Evolutionary Ecology. 12(2): 153-164.

Abstract:
Predation was a powerful selective force promoting increased morphological complexity in a unicellular prey held in constant environmental conditions. The green alga,Chlorella vulgaris, is a well-studied eukaryote, which has retained its normal unicellular form in cultures in our laboratories for thousands of generations. For the experiments reported here, steady-state unicellular C. vulgaris continuous cultures were inoculated with the predator Ochromonas vallescia, a phagotrophic flagellated protist (’flagellate‘). Within less than 100 generations of the prey, a multicellular Chlorella growth form became dominant in the culture (subsequently repeated in other cultures). The prey Chlorella first formed globose clusters of tens to hundreds of cells. After about 10–20 generations in the presence of the phagotroph, eight-celled colonies predominated. These colonies retained the eight-celled form indefinitely in continuous culture and when plated onto agar. These self-replicating, stable colonies were virtually immune to predation by the flagellate, but small enough that each Chlorella cell was exposed directly to the nutrient medium.
Hmm...a unicellular organism suddenly forming a multicellular system upon a change in its condition (introduction of a predatory species).

Let us not forget differentiation in one of my favorite organisms, cyanobacteria, where certain bacteria will differentiate from the rest of the colony to carry out nitrogen fixation. Seems like something a multicellular organism might do (selecting certain cells to carry out specific tasks).
 
  • #30
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Originally posted by damgo
^^^ Why don't you define criteria for exactly what you mean by 'evolution,' if the examples above do not suffice? There are examples of speciation, as well as examples of dramatic phenotypic change -- compare a Dalmation, Chihuahua, and a wolf, for example.

If you expect to see a big evolutionary change that takes ~1,000,000 years done within the last 100 or so, it's obviously not gonna happen...
Yes, OGO, it will be difficult to claim that the process of natural selection doesn't work or that instances of it cannot be found. By it's very definition it must work given our laws of physics. But I will agree that this does not necessarily mean that it is the "full" explanation for the variation we see. Just because A leads to B doesn't mean that all instances of B came from A.

So I think there is room to challenge but I don't think your current approach is the right one.
 
  • #31
Phobos
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Originally posted by O Great One
I guess a simple "no" would have sufficed. :smile:
Did you check out those links I provided? The answer was yes.
 
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