Author Topic: Phenotypic Plasticity & Polyphenism  (Read 2940 times)

ProfessorDavey

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Re: Phenotypic Plasticity & Polyphenism
« Reply #25 on: June 04, 2020, 11:23:55 AM »
With all due respect for your professional knowledge....the fact that you are a professional scientist is probably the problem. The mind is too caught up in details to understand the broader point I am making.
No Sriram - as a professional scientist I am objective and base my understanding on actual evidence - my understanding is evidence based. And frankly some of your comments are so woeful ignorant of a basic understanding of genotype and phenotype to be painful. These are both scientific terms with scientific meanings. If you want to discuss them go away and learn what they mean, and do not patronise a professional scientist who has spent his last 30 years studying this - my first scientific paper on the topic was published in 1989, my most recent (in Nature Materials) came out just a couple of days ago.

Phenotype changes that are generated to fit the environment ...cannot be based on random variations. There has to be an intelligent (responsive) cause for them.
No there doesn't - there just needs to be a mechanism whereby the control of a process is influenced by an environmental cue - and we are well aware (maybe even you learned this in school) that protein function is massively influence by temperature, pH, osmotic conditions etc - in other words key factors that might change in the environment and for function to adapt to.

That's all I have to say...
So 6 words from Sriram over-rules countless studies on the subject performed by researchers too many to count over hundreds of years.

Owlswing

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Re: Phenotypic Plasticity & Polyphenism
« Reply #26 on: June 04, 2020, 01:03:48 PM »

:) Seems to me, having listened through without pausing to take it in, that since the human species evidently already has whatever adaptations are necessary for survival, they are probably and quite naturally taking advantage of them!


It is a shame that this post of yours is the last one that I understood on the thread!

I sometimes wonder if a university degree in some of the sciences should be required as acceptance level for a poster on this Forum!

I know that I am un-educated and reading some posts here proves it beyond doubt!

I ain't quitting because of it though!
The Holy Bible, probably the most diabolical work of fiction ever to be visited upon mankind.

An it harm none, do what you will; an it harm some, do what you must!

ProfessorDavey

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Re: Phenotypic Plasticity & Polyphenism
« Reply #27 on: June 04, 2020, 01:26:51 PM »
It is a shame that this post of yours is the last one that I understood on the thread!

I sometimes wonder if a university degree in some of the sciences should be required as acceptance level for a poster on this Forum!

I know that I am un-educated and reading some posts here proves it beyond doubt!

I ain't quitting because of it though!
Sorry - let me try to explain, perhaps without the use of scientific terms.

Image our DNA is like a piano - our DNA is broken down into little sections called genes. Think of these as individual notes on a piano. When we press the key on a piano 'turn it on' we produce a note. When we turn on a gene we produce a protein (the equivalent of a note). Except a piano has 88 keys and our DNA has about 30,000 genes.

The genotype is just the available genes (all 30,000 of them) a bit like the 88 available keys on the piano. But with a piano, although there are 88 available keys I only make a sound if I play them, and I only make a tune if a play certain ones in a particular order. The phenotype is a bit similar to that - it is based on the genes that are turned on and the tune is the function of those proteins that are produced.

So far so good - hopefully.

But our DNA is a bit more complicated than a piano (apart from having 30,000 genes rather than 88 keys). This is because some genes can be silenced - the equivalent of locking a piano key, so that however much we might want to play that key we cannot. So we may find we can only play certain tunes and not other ones.

But all sorts of environmental cues can act to silence or unsilence the genes - a bit like something being able to lock and unlock the notes on a piano allowing different tunes to be played. So in terms of our phenotype (the tune we can play from the available notes) those tunes can adapt to the environmental conditions as those environmental cues unlock some genes (or piano keys) while locking other ones.

SusanDoris

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Re: Phenotypic Plasticity & Polyphenism
« Reply #28 on: June 04, 2020, 01:37:58 PM »
It is a shame that this post of yours is the last one that I understood on the thread!

I sometimes wonder if a university degree in some of the sciences should be required as acceptance level for a poster on this Forum!

I know that I am un-educated and reading some posts here proves it beyond doubt!

I ain't quitting because of it though!
:D :D I should think not indeed!!  Funnily enough, I just came back to this topic in order to post the following question:

Does anyone have a simple word  (or two) to take the place of the titla of the thread which Synthetic Dave reads every time I have the SuperNova highlighting box on it?
The Most Honourable Sister of Titular Indecision.

Sriram

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Re: Phenotypic Plasticity & Polyphenism
« Reply #29 on: June 05, 2020, 07:31:18 AM »
No Sriram - as a professional scientist I am objective and base my understanding on actual evidence - my understanding is evidence based. And frankly some of your comments are so woeful ignorant of a basic understanding of genotype and phenotype to be painful. These are both scientific terms with scientific meanings. If you want to discuss them go away and learn what they mean, and do not patronise a professional scientist who has spent his last 30 years studying this - my first scientific paper on the topic was published in 1989, my most recent (in Nature Materials) came out just a couple of days ago.
No there doesn't - there just needs to be a mechanism whereby the control of a process is influenced by an environmental cue - and we are well aware (maybe even you learned this in school) that protein function is massively influence by temperature, pH, osmotic conditions etc - in other words key factors that might change in the environment and for function to adapt to.
So 6 words from Sriram over-rules countless studies on the subject performed by researchers too many to count over hundreds of years.

Prof D

Just a quick final comment...

Evidence is not something absolute. It is what you are able to observe and put together at any point of time. There are lots of things for which the evidence is not yet apparent which would get uncovered by and by. Sometimes we merely have to make up our mind to see the evidence. It depends on basic assumptions and perspectives.

You talk of control processes induced by environmental cues and also of .... random variations.... in the same breath. Obviously they don't go together.

Not all internal processes are like temp changes. Take a chameleon for example. It changes colour within minutes of stepping on to a different surface. Sometimes it is even half brown and half green at the same time as it moves, very slowly, from one coloured surface to the other. There is obviously some internal process (I am not interested in details of this process...pl note) that communicates the outside colour and some mechanism that makes the changes take place suitably.

It is this sort of a specific responsive process that I call Intelligence. While all animals and plants may not be as immediately responsive as a chameleon, they all must have other processes by which such changes happen over time.  All these are intelligent responses and not random variations that just happen to coincide with the environment.

Survival is clearly an objective of life (this is a philosophical point...not a scientific point) and organisms are clearly meant to survive and develop. Suitable mechanisms will naturally be present to enable these objectives to be met.

Cheers.

Sriram

ProfessorDavey

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Re: Phenotypic Plasticity & Polyphenism
« Reply #30 on: June 05, 2020, 09:43:44 AM »
Evidence is not something absolute. It is what you are able to observe and put together at any point of time. There are lots of things for which the evidence is not yet apparent which would get uncovered by and by.
That is true and we develop theories which represent the best explanation for phenomena based on the evidence available at that time. And of course we need to continue to strive to get more evidence - often the new evidence cements the solid of the theory, but sometimes new evidence radically changes our understanding.

Sometimes we merely have to make up our mind to see the evidence. It depends on basic assumptions and perspectives.
Which is, of course, what science and scientists are all about - we are ablated to take account of all the evidence, and trust me if you don't one of your peers will pull you up over your failure to see the evidence.

You on the other hand seem serially to actively choose to ignore evidence, where it doesn't fit with you prejudged view - that is exactly the opposite of make up our mind to see the evidence, you seem to have made up your mind to ignore the evidence (see below as an example).

You talk of control processes induced by environmental cues and also of .... random variations.... in the same breath. Obviously they don't go together.
Yes they do - did you even bother to read what I have written in earlier posts?

The random variation (e.g. gene mutation that results in a slight change in the configuration of a protein, meaning its active site becomes hidden and inactive under certain osmotic conditions) leads to a situation where the activity of that protein becomes under the control of an environmental cue (in this case osmotic conditions, which relate to hydration state). Prior to that random gene mutation that protein would not change configuration in response to osmotic change in a manner that altered its activity.

Not all internal processes are like temp changes.
True, but you would be surprised at the number of biological processes that are mediated by a very small number of elements of fundamental chemistry - specifically temperature, water content (osmotic), concentration of ions, pH and of course these are all interlinked.

Take a chameleon for example. It changes colour within minutes of stepping on to a different surface. Sometimes it is even half brown and half green at the same time as it moves, very slowly, from one coloured surface to the other.
Really poor example to choose as the colour change in chameleons is linked to both thermal processes and osmosis - their dual layered skin and pigmentation is a common adaptation for thermal regulation in lizards, however, of course most lizard do not demonstrate the ability to change colour in the manner of the chameleon. That process is controlled osmotically, in a layer of the skin that contains nano-crystals - a change in the osmotic environment (see above) alters the spacing of the crystals resulting in changes in light scattering and reflection - producing the perceived colour change. The chameleon controls this through sensor/control/feedback systems involving their own detection of surrounding colour patterns.

There is obviously some internal process (I am not interested in details of this process...pl note) that communicates the outside colour and some mechanism that makes the changes take place suitably.
Yes there is some internal process - I've explained it.

You claim not to be interested in details of this process which effectively means you aren't interested in the evidence - you are clearly doing the reverse of make up our mind to see the evidence you have made up your mind to ignore the evidence (as you don't even want to hear it). And of course you need to understand the evidence and the process - otherwise it is the equivalent of discussing thunder and lightning without understanding how they occur (down that route lies Thor and the evidence tells us thunder and lightning are purely natural processes).

It is this sort of a specific responsive process that I call Intelligence. While all animals and plants may not be as immediately responsive as a chameleon, they all must have other processes by which such changes happen over time.  All these are intelligent responses and not random variations that just happen to coincide with the environment.

Survival is clearly an objective of life (this is a philosophical point...not a scientific point) and organisms are clearly meant to survive and develop. Suitable mechanisms will naturally be present to enable these objectives to be met.
No you have it entirely the wrong way around.

The oak tree in my garden doesn't have survival as an objective, it is clearly not meant to survive. It is simply well adapted to its environment so will survive - so survival is an outcome not an objective. Some species and individual organisms will be better adapted to survive in a particular environment - those will be more likely to serve and reproduce and therefore will be selected for. Others which are poorly adapted to the environment will not survive and will disappear from that environment.

And there are countless traits that may enhance or reduce the likelihood of survival (e.g. resistance to drought or other environmental extremes etc etc). I fully accept that in higher conscious animals a 'survival instinct' may also be a trait that develops which enhances the likelihood of survival, but that is merely another evolutionary trait seen in a small number of species rather than a global unifying objective.

« Last Edit: June 05, 2020, 09:53:47 AM by ProfessorDavey »