Evolution Theory

Great Debates
181

I assume you mean genetically passed on! I’m sure you don’t dispute that an acquired trait like making stone spears or beaching oneself to hunt seals can be passed on.

And yes, acquired traits can be passed on. However the mechanism is a little unusual.

( http://www.hhmi.org/news/lindquist.html )

Mutations for various traits occur in sections of the DNA that aren’t normally expressed. These areas have essentially been locked away. When an organism is subjected to stressors protein conformational changes allow these areas to suddenly become expressed.

As a result we see situations where a fly that is starved as a maggot develops into an adult with a phenotype that’s totally incompatible with the parents according to clasic Mendelian genetics. The phenotype has been acquired in this generation. However the fly is not genetcally any different to what it would have been had it not been starved. The traits are just as acquired as if the embryo had been surgicallly altered.

However in these situations the fly’s offspring will also have the same ‘deformities’.

There is evidence coming to light now that specific stresses may trigger variability in specific regions of the genome. Potentially this could be saying that starvation will lead to variability within the digestive tract for example.

Of couse there’s no evidence of that degree of specifcity yet. However a plausible mechanism for Lamarckian evolution exists. Because of this it’s no longer the ‘flat earth’ explanation that it was 10 years ago.

Interestingly it seems that the acquired changes are beneficial in the new environment far more often than simple reading of previously ignored random mutations should allow. About 25% of the changes seem to be beneficial, whereas simply reading over random mutaions should only produce novel advantageous changes in a very small monority of cases.

It’s still early days in investigating these mechanisms, and the investigators are still inducing gross changes by applying massive stressors. It’s kind of like investigating how well a city’s fire fighting systems work by firebombing 10 downtown blocks. Yeah it tells you what the fire department and the National Guard can do, but it doesn’t allow you to investigate the subtle effects of sprinkler systems and people with fire extinguishers, which are equally vital in controlling fires.

Maybe small stresses on neck muscles can induce minor variability in the giraffes neck. Or maybe it will turn out to be largely irrelevant. But while we have a proven potential mechanism Lamarkism is back on the table in at least as a possibility.

So to make a long answer short, yeah it’s possible for an induced variation to be inherited.

182

Thanks, Blake, that’s interesting. What I remember of Lamarkism is the old cutting-the-tails-off rats thing from high school (20 years ago). I didn’t realize it had changed so much. I stand corrected.

183

That’s the great thing about evolutionary science: it is a science and not a religion. If they discover incontrovertible proof of Lamarkism next week then there’s no problem with accepting it. As it is we have minor instances of Lamrkian mechanisms at work, and that’s also incorporated.

As others have pointed out the ‘cutting tils off mice’ idea is a bit of a straw man. It requires a false dichotomy between Lamarkism and natural selection. Of course this doesn’t exists. What Lamark proposed was that a giraffe that had to put stress on its neck to survive would have a giraffelet with a slightly longer neck as a result, and that that girffelet would have more young than would giraffes with shorter necks.

Given the state of knowledge of the mechanisms behind genetics at the time it made perfect sense. Darwin himself was a firm believer in such Lamarkian mechanisms and invoked them numerous times to explain the beginnings of traits. The difference with Darwin was that he could see that once a trait was initiated by Lamarkian mechanisms, it could then continue to develop without need for more input simply by culling those without that trait. Lamark never quite embraced that idea fully.

The tailless mouse experiment never allowed for natural selection, and so of course is a straw man.

It’s also flawed in another respect. Since some mice presumably died or got ill as a result of the amputations we could equally say that it disproves mutation-driven evolution couldn’t we? Since within that population being born with a tail reduced reproductive fitness, then we should have see the mutation into tailless forms shouldn’t we?

184

Fossils of humans, birds, and large mammals are never, repeat never, found with or below those of dinosaurs.

Fossils of dinosaurs are never, repeat never, found with or below those of early amphibians.

Fossils of early amphibians are never, repeat never, found with or below those of early plants.

It is incontrovertible that these different types of creatures lived in different ages separated by millions of years.

This is not an assumption, this is a fact as sure as the world is round. Questioning it is as reasonable as questioning whether or not you can fly by flapping your arms.

185

Nothing is repeatable, nothing ever happens the same way with the same circumstances. Each individual is unique, one is certainly not a replacement for another. Physical things like houses, and land change also with each passing second. Everything is akin to energy and nothing “dies” by our definition of dying. You will always be you for eternity. But you will grow spiritually and become brighter, holding more wisdom. In the spirit world all events are simultaneous, there is no time or space. What could be simpler.

186

Yes, Leroy, nothing ever happens the same way with…

You know, if that were true, there’d be no such thing as the scientific method, and cars wouldn’t work.

But within the limits of living beings, that’s an okay approximation. And the point of the discussion.

Let’s take a herd of deer. Over time, some of them get old, and die. Or at least their physical bodies do. And new deer are born. And they’re different deer. Some of them are really, really good at being deer and they mate a lot and have more babies. Then they grow older and die, and their babies grow up. And some of those are really, really good at being deer. And so on. Eventually, all the deer in the herd will be descended from that one deer who was really good at being a deer.

Nothing to do with the spirit world, Leroy. In the spirit world, this may have all happened at once, but we can’t see that, can we?

So, with our poor mortal senses, we see evolution. That’s all it is.

This spirit world concept of yours… I’d like to see some cite of it, and how it’s relevant to the discussion. Because it sure sounds like you’re talking all silly.

187

I’d be quite interested to hear how this works:

Everything happening all at once? A baby is born at the same instant it’s being conceived, at the same time he’s dying, all whilst both all the ancestors are also simultaneously being conceived, born, growing up and dying? Really? Either time must still pass in this ‘spirit’ world of yours (things must occur with some form of linear progression) or those ‘souls’ are just existing completely insensate without any form of interaction or movement along any given time-line. All events occurring simultaneously would even imply we are all there already.

The rest of your post sounds a little like Heraclitus’s famous dictum “You can never step into the same river twice,”, except you state that people can’t change in the same way inanimate objects can. Is that your conjecture? It’s quite interesting for me to try and grasp what it is you truly believe. Can you please clarify?

188

Warning: lekatt’s idea of clarification (see especially pages 21-32).

189

It seems silly until you add the dimensions of time and space. These dimensions are also part of the physical and must be considered in all calculations. In my readings, I have noted that some scientists are beginning to understand the experimenters effect on the experiment. Things like expectations, organization, and so-forth taint all experiments. We are learning all the time.

190

Lekatt, you need to understand your limitations a bit more and quit blowing your horn so much.

191

I can try.

Eternity is sometimes called the eternal now, try to remember when you were so involved with some project that time seemed to stand still, yet, hours had passed. Eternity is something like that, there is no linear progression in spirit. Actually, we young ones come into the physical to learn in a time oriented world because it is easier. Things move slower, thoughts to creation take a lot of time, etc.

If you want to experiment, try bringing your thoughts back into the moment when you noticed them wandering away. Be gentle, it is not easy. We are here to learn control of thought patterns, focusing them into positive events.

I hope this helps some.

Love
Leroy

192

Which, Leroy, is irrelevant to my point. If you choose to organize things by location on a timeline, as so many people do… it helps making sandwiches, for example. Always make sure you have bread before you spread the peanut butter… Yes, the essential timelessness of all things means that eventually the bread will be there, but you’re still going to wind up with peanut butter on your counters if you try it the wrong way round…

IF you choose to organize things on a timeline from the past to the future, living creatures die and other living creatures take their place.

Am I right, Leroy? Elvis is dead. Or he just went home. Either way, N’sync took over the top of the charts.

193

Well, that kills the idea of survival of the fittest.

194

Now, now, Tom, evolution doesn’t always mean a higher form of life, does it? I chose that example on purpose. :wink:

195

So we may not wind up as luminous beings of energy some million years hence? Back to tails and flippers for the lot of us!

196

That’s precisely why amateurs shouldn’t mess around with the philosophical implications of atemporality. Those perspectives take practice.