Comments on: Evolution on the fly: Look, Ma! No genes!

By: david lloyd thomas

david lloyd thomas — Mon, 25 Jul 2011 12:50:42 +0000

I am more than confused that this example of co-existent benefit is considered an evolutionary change.

1. The nematode was harming the fly’s reproduction.
2. The bacteria’s introduction harmed the nematode’s reproduction.
3. That second introduction allowed the fly to reproduce according to design.
4. There is no evolution here.

This “fly/nematode/bacteria” interaction is not even the same as the Fig Tree/ Fig Wasp relationship that has apparently existed as necessary for their interdependant existence.

If a virus came along and interferred with the bacteria, then the nematode would be back at work making its home in the fly. The fly would be idential to the fly before bacteria versus after bacteria. That is, there would be no change in the fly. No evolution has taken place.

In fact, this is not even an example of micro-evolution.

By: Manu Ganji

Manu Ganji — Thu, 22 Jul 2010 06:53:22 +0000

“Testing preserved flies from the early 1980s, Jaenike found that the helpful bacteria were present in only about 10 percent of flies in the eastern United States. By 2008, the frequency of Spiroplasma infection had jumped to about 80 percent.” <–what does that mean?

Does it mean… they preserved these files all along from 1980s – 2010 in isolation and they found the proportion of bacteria infected flies to increase? Please help. Thanks in advance.

By: Roy Niles

Roy Niles — Tue, 20 Jul 2010 09:14:23 +0000

Darwin’s theory allowed for the heritability of learned behaviors, but largely because of the Weismann Barrier hypothesis, the neo-Darwinians held that such experiences were not to be considered as effecting the selection process – hence the belief that the organism’s purposes could play no part in its evolution – with the further belief that organisms had no purposes of their own to begin with. This belief is now changing as it is recognized that organisms act.in anticipation of results, and learn from their mistakes in a trial and error fashion. These experiences, to the extent that they are successful, eventually become instinctive. And heritable.
Instincts are purposeful, even though the organism won’t know their ultimate goal when acting as the instincts direct it to. There is a form of intentional choice involved here based on short term expectations – which if successful lead to further choices as the instinctive process directs. Not all parasites will attain the results their instincts ultimately were after. Those that do will be rewarded by their replication. Instincts will be enhanced by experiences over time as well. That’s the short version. These ideas are part of the curriculum in most universities, and much as been written on this by the modern evolutionary biologists, such as Shapiro, Margulis, Lamb, Jablonka, Adduter, Rose, Ayala, and numerous others – including Varela, as I first mentioned. That paper will explain autopoiesis much better than I can. This doesn’t invalidate microevolution, it just puts purpose back in the equation.

By: David

David — Tue, 20 Jul 2010 07:33:01 +0000

Aaron – You’re quite welcome. I didn’t mean to be condescending, and I certainly hope I wasn’t.

Social evolution is quite an interesting phenomenon. Until recently, biologists believed that culture had actually stopped human evolution, and so we’d be stuck in a Homo Sapiens state until the end of, well, at the very least, the end of all culture.

However, the newest research (and if you think about it a little bit, I think you might agree) suggests that culture has exactly the opposite effect: It accelerates evolutionary change.

On the other hand, I do agree with enirdlinger: I think this concerns more the physical inheritance of Spiroplasma and the increase of fly-Spiroplasma symbiosis frequency than it does to evolution unrelated to genes. I have never heard of other examples though…. for some reason, I just don’t think of mitochondria —-> eukaryotic cells evolution path as the same, but that’s just me.

And at the risk of kicking a dead horse:
Roy, I thought the concept of an autopoeitic system was that it was a system (usually living) that has a network of operations and or processes that is able to respond, to some degree, to perturbations in the system. This STILL falls within the theory of Microevolutionary Theory, which is, as you will undoubtedly know, just the microscopic extention of Darwin’s theory of Evolution.

By: enirdlinger

enirdlinger — Mon, 19 Jul 2010 13:34:36 +0000

WJV’s comment concerns social evolution and is an interesting concept. The difference between that and what is discussed in this article is that a material change occurred within the individual’s body and is now transmitted through sexual reproduction. I think that current thinking is that our miochondria evolved in a similar manner from a symbiotic relationship between two organisms (our DNA comes through our mother) , but can think of no other similar inheritance.

By: wjv

wjv — Mon, 19 Jul 2010 06:18:50 +0000

So are these researchers are claiming this is the first instance of evolution via a mechanism that isn’t caused by genetic mutation? Because I can think of many examples of evolution in humans not caused by genetic mutations… they all involve technology.

Think about it: if obtaining a bacterial symbiont equates to selective force, then it’s analogous to say that knowledge of agriculture was selective, so would be powered transportation, computing etc. Vast majorities of our human population are “colonized” by these technologies so can these researchers look at that phenomenon the same way?

By: Roy Niles

Roy Niles — Mon, 19 Jul 2010 04:35:34 +0000

How wonderfully bright and interesting of you. Care to tell us what you learned that makes you smarter than Francisco Varela?

By: JTK

JTK — Mon, 19 Jul 2010 03:17:01 +0000

Bugger off, woo-troll.

By: Roy Niles

Roy Niles — Sun, 18 Jul 2010 21:30:08 +0000

If you can, why don’t you?

By: enirdlinger

enirdlinger — Sun, 18 Jul 2010 15:05:28 +0000

Roy, like many bores, has hijacked the conversation on a really interesting article. Can we ignore him and redirect the discussion in a way interesting to a larger group of people?