[Nils Cordes]

Nils Cordes  asked the Naked Scientists:
   
I recently listened to your interview with John Jaenike. I was impressed by the research they did on Drosophila symbionts, and after having read their article, I followed up on your report by posting a short summary of that research on a blog on evolution that I'm running.

Anyway, readers have been enraged by me suggesting that this adaptation of Drosophila populations to the nematode threats was evolution. Most of them disagreed. Ben, you suggested it was a novel mechanism, with which I tend to disagree because the mechanism is quite old. But I'm wondering, can you really call this type of adaptation "evolution"? I discussed this with colleagues, who were split down the middle. But some argued that without genetic alterations, there can be no evolution. (Like, if I introduce a fox into a chicken pen, the remaining chickens that have not been eaten, have not evolved.) I can see their point, but I still think that there's a mechanism of evolution at work here (in Drosophila) that does not require gene alteration. At least not for now.

So, my question is (one that might be worth putting up for question of the week): Can evolution act on something other than genes? I read about prions, but know too little about that. What about physiological changes caused by pathogens? If they, like in this case here, establish themselves ion the population, do we really need genetic changes to be allowed to call it evolution?

Your help would be much appreciated. But I'm also quite interested in this subject matter, so feel free to discuss it with the rest of the group.

I'm not participating in your survey this year, but let me tell you that The Naked Scientists is by far the greatest science podcast out there, internationally. Don't change a thing. ;-)

Cheers,

Nils
What do you think?

[chris]

The heritable material transmitted between cells is DNA, which is organised into functional units called genes. The information encoded within the gene sequence, or associated with the gene sequence (such as epigenetic marks), is therefore the main means by which the process of evolution is achieved.

However, you could argue that knowledge, which doesn't need DNA, can also make an individual "fitter" and can also be passed between individuals or shared around a population. This sort of information is dubbed a "meme" and is an example of the sort of inheritance to which you refer.

[RD]

This is not biological,  but uses evolution ... https://wikipedia.org/wiki/Evolutionary_computation

[evan_au]

Evolution can also act at the level of species and ecosystems.

Ecosystems can occur at various levels, such as planets, oceans, continents, islands, microbiomes, cancer masses and biofilms.

[Kryptid]

The original definition of evolution was "descent with modification". This was before we knew about genes. The current definition is "changes in allele frequencies in a population over time." However, epigenetic changes over time could also be considered a form of evolution. Epigenetic markers change the way that genes are expressed and these can be passed on to offspring from their parents.

[Colin2B]

.....if I introduce a fox into a chicken pen, the remaining chickens that have not been eaten, have not evolved.

Nils
What do you think?

I think that if the surviving chickens had a gene that allowed them to fly to the top of the chicken coop, or run faster, then that gene would be passed on to their offspring.

[puppypower]

.....if I introduce a fox into a chicken pen, the remaining chickens that have not been eaten, have not evolved.

Nils
What do you think?

I think that if the surviving chickens had a gene that allowed them to fly to the top of the chicken coop, or run faster, then that gene would be passed on to their offspring.

This would work in a natural environment, but in an artificial environment such as controlled by humans, humans will replace natural selection with artificial selection. They would tend to choose the less mobile chickens, for breeding, that make the best oven roaster.

The same is true of the human species. Modern medicine creates an artificial environment, that does not evolve humans based on the best heath characteristics. Medicine creates an artificial selection environment, which is evolving humans toward a lower natural health denominator, in terms of genes. I am not sure if getting less advanced is called evolution or de-evolution. One can see this in the rise of allergies.

When I was young, I never heard of peanut butter allergies nor did I ever know anyone who could not eat it. Today, many bodies can't process this. This could be epigenetic, where gene expression is modify based on signals from the brain; market conditioning and concerned parents.

Water is continuous in the body. The equilibrium shape of the DNA is defined by an equilibrium within the water. The same is true of the brain and neurons, with nervous wiring everywhere in the body. This wiring can transmit and conduct aqueous equilibrium; mind over matter.

[Colin2B]

One can see this in the rise of allergies.

When I was young, I never heard of peanut butter allergies nor did I ever know anyone who could not eat it. Today, many bodies can't process this. This could be epigenetic, where gene expression is modify based on signals from the brain; market conditioning and concerned parents.

Some allergies eg nuts appear to be due to a lack of early exposure - before age of 3 is often quoted.
http://www.nhs.uk/news/2016/03March/Pages/Early-exposure-to-peanuts-cuts-allergy-risk-in-children.aspx