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I'd like to start first by saying that I don't believe in creationism at all, nor any non-Darwinian-evolution explanation of the diversity of life on Earth. The theory, the fossil record, and the genetic, morphologic, and biochemical evidence are more than overwhelming in support of it.

Also, I understand that the term 'macro-evolution' is a "weasel word" invented by creationists to make a bogus distinction of two supposed kinds of evolution.

But for this question, I think the term is useful. I'm happy to take any corrections or qualifications in comments or answers.

I wonder if there has been any long-term experiment performed to attempt to induce 'macro' changes in a species-- something that would make this lab-based population considered to be a subspecies, or even a different species, if it were found in the wild.

I'm aware of the long-term E. Coli experiment that resulted in bacteria that developed mutations that allowed them to completely metabolize citric acid. I understand that's a change of a few genes (amongst other recorded changes).

What I'm looking for is something a little larger, more than a new protein. I was thinking something like 1. a new organelle, 2. a new type of cell or tissue, 3. a new organ, or 4. a new type of limb or radically different limb use (something like reptilian jawbones re-purposed in mammalian ears_.

I understand there are numerous incidents of organisms losing useless features, such as eyeballs in dark caves, flight ability, etc. For this experiment I don't think it's enough to show the loss of something-- genes turning off, but novel characteristics must arise. To rebut creationists, I think it's necessary to show 'new' information, not just loss of information (I'm speaking of the genes responsible for morphology).

With my laypersons' imagination, I was thinking of a species with a relatively fast reproductive cycle, put in an environment that had some selective pressures. Perhaps one without much room to fly, not enough food, but plenty of food in a water area where they couldn't normally get to it. Something that might encourage them to adapt to taking to water to exploit a new food resource.

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  • $\begingroup$ The timescales over which your suggested changes could happen makes them infeasible to directly observe. Of course, there is plenty of indirect evidence to support the idea that such processes have already occurred. Also, science isn't concerned with rebutting creationists. We make observations and develop theories to explain them; that's it. $\endgroup$ – canadianer Oct 17 '15 at 20:53
  • $\begingroup$ @canadianer If you know, what is a rough estimate for the time of any of these features to develop? I know there's not a (meaningful) average, and that no example would be representative, but any that you know of offhand would be informative to me. $\endgroup$ – user151841 Oct 17 '15 at 21:01
  • $\begingroup$ @user151841 We could calculate an average (if if it would carry little info) if we could accurately define the evolution of a specific trait. But the question does not so there's really no way to answer it. I just tried to give a few examples that are of eventual interest. For more, we will need a more accurate question. $\endgroup$ – Remi.b Oct 17 '15 at 23:34
  • $\begingroup$ Would you accept Humanized mice that can be infected with the HIV or with Kuru or Creutzfeldt - Jakob brain homogenates and develop human prion disease? Wild type mice could not be infected with either the HIV virion or the misfolded human prion protein. $\endgroup$ – AMR Oct 18 '15 at 0:11
  • $\begingroup$ @Remi.b That is why I say there's not really a (meaningful) average. To take an example, we could say that, since it took ~ 10 million years from pakicetus to Mysticetes, two clearly different species, macroevolution can take about 10 million years (evolution.berkeley.edu/evolibrary/article/evograms_03) . Of course, tough, we want to find a shorter example in the interests of this experiment. But since the distinction between 'species' get fuzzier the more closely related populations are (subspecies, etc), finding the 'shortest' timeframe becomes more difficult. $\endgroup$ – user151841 Oct 18 '15 at 16:14
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Issue with the question

The question of what is an evolved phenotype that is "seemingly significant enough to the layman to be called macro-evolution" is very unclear and it makes it hard to answer.

Most experimental evolution are performed on lineages that have very short generation time (for obvious reasons) and on these lineages it is hard to even imagine the evolution of something that a layman would consider to be "significant enough to be called macro-evolution".

The whole issue is that one will probably consider a change in phenotype to be "seemingly significant enough to the layman to be called macro-evolution" if it occurs on lineages that have long generation time and therefore cannot be observed within a lifetime.

The question interesting. However, I think the best one can do is to look at the wiki article for experimental evolution who already offer quite an interesting list of examples. I tried below to highlight a few cases of eventual interest


Long term artificial selection on "large living things"

If one wants to consider artificial on "large living things", then probably artificial selection on crops and cattle will be a good place to look at. I think I don't need to list and make extensive description of how artificial selection has changed their phenotypes (and genotypes). Consider the pigs, banana and corn as examples.

A few evolved features that has evolved in labs in small organisms

We have observed evolution of multicellularity form unicellular organisms, observed new metabolic pathways and change in ploidy level just to cite a few major things that we evolved.

Lenski experiments

The Lenski long term experiments is the longest in lab evolution experiment performed today. They made a lot of different observations and not only the case of citric acid metabolization that you mention. Note that being able to metabolize a new compound is a pretty considerable evolved feature that only those who can't go further than considering evolution of extra legs as something significant would fail to appreciate.

Drosophila and Waddington's experiment

If one must restrict I suppose that looking at experimental evolution on Drosophila would be our best bet.

Change in allele frequency through selection is a relatively fast process. Creation of beneficial variants through mutations is often the limiting process. Cases where very different phenotypes exist in natural population and selection over these phenotypes (change in frequency only) will probably not be considered to be "impressive enough". However, one can consider Waddington's experiments (and further experiments inspired by Waddington's work) as an example of experimental evolution where standing genetic variance existed before the experiment started but was hidden in the environment they experimented (the exact process here might well be too advanced for a layman). Waddington in his experiments showed one can evolve Drosophila to have a double thorax or lose their halteres in only 20 generations.

Other Drosophila experiments

We evolved Drosophila to live in hypoxic conditions. It took about 200 generations that is more than 4 years. We have also selected Drosophila for cognitive abilities and food preference (and many other things).

Note on the term "macro-evolution"

The term "macro-evolution" hasn't been invented by creationists. It has been invented a long time ago, in 1927 by a russian entomologist. T. Dobzhanski and E. Mayr (two famous evolutionary biologist) have used this term without ever quite defining it. Because the term was never correctly defined, the vast majority of evolutionary biologist have either criticized the term.

It is true that the term is now sometimes used by creationist as any poorly defined term is one of the finest solution to build questions that can't be properly addressed due its lack of clarity.

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