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Evolution is for survival in different environment. What exactly survives ?
Krushna Mavani
Saturday, 05 July 2008 07:09 UTC
Well, I am not a biologist but I have this question in my mind.
If we evolve, our genes also modify from generation to generation. Then what does remain as such in the same form? For all the generations till now, nothing in our body seems to be remaining in the same state. We have evolved thus far for existence of what? DNA also changes, then what exactly survives? And for the shake of whose existence we are evolving?
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Interesting question, Krushna.
The short answer to your first question – what exactly survives? You are on the right track. Nothing survives “exactly” the same – that is the nature of evolution. Life itself persists, and continues to evolve, for it is dynamic by nature – although there may be periods of very little change in some species, most continue to change.
As for the last question, let me pose a counter: why must we evolve for anyone’s sake? Evolution simply is – as a basic property of life, and doesn’t need any other justification. When you throw an apple up into the air, it falls down towards the earth – does it do so for anyone’s sake? Or simply because that’s what it does?
For a deeper understanding of evolution, I would invite you to take my class on the topic starting next month! Given that you probably won’t be able to attend that, allow me instead to point you to a very accessible alternative, Carl Zimmer’s wonderful popular book Evolution: The Triumph of an Idea.
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Thanks for your answer Madhusudan, for my first question. For second answer, as I am a science student, I knew that evolution is property of life but I am taught that evolution is survival of human-kind (or any kind) and then what survives finally? – Nothing because everything has to change. Except life nothing seems survive, is not it?
I have two more questions.
1) After a child is born, does the child repeat whole evolution process starting from a cell?
2) If so, then in the growing stage, does the child add his/her evolution-patch to the genes?
In fact, reading that book will really take a long time, so if I can get answers for these. I am asking just for my curiosity, I am actually a physicist.
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I am taught that evolution is survival of human-kind (or any kind) and then what survives finally? – Nothing because everything has to change. Except life nothing seems survive, is not it?
In the short term, evolution indeed involves the survival or persistence of species (or kind). In the long run, species evolve and change (gradually for the most part), so yes, no species survives forever. Some of the genes may last a very long time, though, and come to be shared across species. Within genes, the genetic code itself (the translation of sequences of DNA into amino acids which are building blocks for proteins) has remained more or less the same across all living organisms.
1) After a child is born, does the child repeat whole evolution process starting from a cell?
No. It was thought that this was the case – that ontogeny (growth of individual) recapitulates phylogeny (evolution of lineage) – but that is now known not to be the case. Some ancestral characteristics are seen during embryonic growth (e.g., apparent gill slits in mammal embryos), but not all, and there is no repeating of any particular evolutionary sequence during growth.
_ 2) If so, then in the growing stage, does the child add his/her evolution-patch to the genes?_
New mutations may alter the genes of an individual. If they occur in non-reproductive cells they can alter their functioning in that individual, and even cause problems like cancers. If mutations occur in gametes (sperm or egg cells) they get passed on to the offspring. E.g., if a mutation were to cause a new trait to appear in an individual (e.g., sickle cell anemia, or lactose intolerance) it will get passed on to the next generation if it is in the gametes.
The important thing to note is that individuals do not evolve, but populations do! Evolution is defined as a measurable change in allele frequencies – i.e., relative frequency of various genes – at the population level. So, to take one of the mutations I mentioned above, one would say that a population has evolved if the frequency of individuals with sickle cell anemia changes between generations. In a sense, you might consider evolution a statistical property of a population rather than something an individual child undergoes.
Given your level of interest I would still recommend you find the time to read at least an introductory book on evolution. Zimmer’s book is actually very well written and fun to read – and shouldn’t take too long! If you prefer, there are also many websites that offer good explanations. A really good one is the Understanding Evolution website from the University of California at Berkeley.
Meanwhile, I’ll try to answer whatever I can here!
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Hello all, Can I also try to answer these questions and we can start a dialectic here-
If we evolve, our genes also modify from generation to generation. Then what does remain as such in the same form?
Might I say I can begin to see that you are from the physical sciences, by your philosophical partiality towards a hybrid epistemic-ontological reductionism.
Let me try to answer your question as simply as possible:
What remains exactly in the same form are follows:
1. The basic molecules – units of biological structure- the amino acids, simple carbohydrates, nucleotides (which are again simple organic compounds constituting our DNA (and RNA) and the basic molecules which go on to form our paunches and cell membranes- the fatty acids and glycerol.2. Next what remains the same are some basic moduli of structural organization. For instance, a cell remains a cell in the sense, for all organisms bacteria to human it constitutes various bits and pieces organized within a protein-lipid envelope.
3. The physics of biological matter remains the same. It has the same “mesoscale properties” (I think that is a condensed matter physics term). It exhibits similar visco-elastic properties- the laws that biological matter has obeyed in its physical and chemical properties has remained the very same over time. It is also an excitable media.
There are other patterns to be found but these three should suffice for now. I will answer your other questions a bit later.
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We have evolved thus far for existence of what?
Isn’t that a philosophical question? The answer to this is not in the realm of contemporary biology. Camus,Dostoyevsky or Aurobindo have approached this question in different ways.
And for the sake of whose existence we are evolving?
Nice answer Prof Katti.
Havent read Zimmer although I think Dr John Maynard Smith would also be an excellent, deep albeit lucid read on the basics of evolution!
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Maynard Smith is great – and likely to appeal to physicists as well. Zimmer is more recent, however, and more up-to-date in terms of current research. Of course, the basic theory of evolution (the modern synthesis) hasn’t changed since Maynard-Smith wrote about it. But we know a great deal more in terms of details now.
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I was away for sometime, so could not reply here.
Thank you for your answers Madhusudan and Ramray. Well, certainly I need a verbal discussion on these with some experts, I feel. Anyway, if not I should try for this book which is suggested by Katti.
The answers given by Ramray seems to be frammed for “physicists vs. biologists” in biological research or for youngsters in schools. Never mind it but I did not mean to offend any paritucal area of science while asking these questions.
Well, yes, the question “We have evolved thus far for existence of what?” is philosophical but looking at the advancement in science, I thought, some might have already gotten answer from scientific point of view. So, the ‘motive of evolution of life’ remains still unknown to us.
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I didnt quite get what you meant when you said my answers seemed to be framed for a “physicists Vs biologists” in biological research. Coming from a physical biology (or biological physics) field, those that I mentioned seem to me the common features which get passed down through generations. There are other “higher order” features like pattern languages for multicellular development or genetic toolkits but I deliberately didn’t mention them as because that would entail lengthy elaborations.
But let me put the spotlight on you Dr Mavani, (for your other comment) in a sense and take the opportunity to learn from you – Is there a motive for the evolution of the universe ?Or rather let us pull back further and question the question- Should there be a motive for the evolution of life? If we treat life-form as simply an error-prone (treat in biology, as heritable but occasionally throwing up variations) replicating open thermodynamic system, which is far from equilibrium, should there be a motive for it to evolve ?
Dr Katti, any insights, corrections, additions?
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Evolution in an universal sense (encompassing living replicating open thermodynamic systems and non living systems) also means increasing complexity in structural organizations in Time.
Time in this specific context can however be observed only as a linear phenomenon, even when it may contain within itself cyclic Time, i.e., perfectly stable thermodynamic states (or to express it in biological terms, like Ramray, as the basic moduli of biological structural organizations) and as such, so the classical theory, inevitably and remorselessly destined to a final death in an universal cosmic entropy! No big bang, like the birth of the universe or for that matter of a human child with a primal scream, but a slow fading away of everything in a warm nothingness or for that matter the silently witnessed natural death of a grand parent.Mind you the modern physics won’t deny you the possible existence of other universes where these laws do not apply! Or the fact that quantum physics will give the blessing of doubt within a microcosmic universe.
The fact is we understand actually less than before, because behind the apparent complexity of the observable universe there resides still more complexity. Einstein probably thought the universe as big as a Galaxy. And Hubble did not know of the new universes imagined by modern mathematicians, physicist and cosmologists to extend well beyond our 4 (space time) dimensions in some unobserved 7 (mathematical) dimensions. And quantum and modern physics think strings and the new particles with their flavors are the basic structures of our universe, because they can not at present go deeper than that. Once another Hubble uses a new nano-telescope you may find a cosmos within a gluon!
Science is a grand story of the humans, how can it be otherwise? And similarly your question concerning the where-to of evolution is also a grand question of the humans? In a way both are philosophical and it is less a question of physics versus biology, but something more substantial but constrained by the trends, paradigms, fashions, instruments, technologies and hopes of the times!
Have you ever wondered at this one crazy thing?
Why were the brains of the Homo sapiens already endowed with an hardware that could produce an Euclid, an Einstein and a Riemann long before there was any actual need for it? They only needed 5% of that primate asset if you consider the selective pressures imposed by the times! Or were the other primates already so advanced that a capability to construct the Euclidean geometry or our religion and poetry was a prerequisite for survival?
I am absolutely not hinting at anything. I personally think it may have been an accident, in fact life itself and the universe may be an accident or the dream of a Brahma! But the most enlightened of modern physicist will probably claim that life and subsequently Intelligence is an inherent property of Matter! This is not the place to talk about our concepts of matter as such.
But we do come to this unavoidable conclusion, that intelligence in its most higher abstract form is also the ability, perhaps an unavoidable one to ask that very question that Mavani has raised. And as such represents a legitimate field of honest scientific enquiry?
Physics has no answer and will probably never have one.
Biology? Not when evolution is perceived only as a measurable change in allele frequencies within populations! This however does not preclude us from attributing intelligence and purposeful functionality to a highly organized state of ants or to a kingdom of the bees!The answer to Mavani’s question can not lie within measurable Quantifying Sciences.
No doubt philosophers like William James, psychologists and sociologists have tried to answer such questions, especially those with an rather imperfect understanding of Darwinism in 19th Century Europe. Most of the latter have tried to explain (rather explain away!) the need for such questions through cultural relativism!What Biology and Physics do not understand is vastly more than what they do.
Just wait 20 years more!
And the answer under the present paradigm to Mavani’s is of course: there is no teleological factor in evolution, but nevertheless the evolution has blessed us with a structure (brain) that does ask such questions, actively seek answers to such questions… and strangely feel disappointed when it does not find the answer?
I have of course my own explanation for this phenomenon. But that won’t answer Mavani’s question in the way he seeks the answer. It too can be considered as explaining it away and to be associated with the predominant paradigm of our epoch.
Willed purposeful acts associated with awareness have been recently attributed to certain species of singing birds, many members of the primates, canines, whales and what not!
Add to such purposefulness some rudimentary language, one time or another you will have word for purpose. This word initially associated with concrete physical acts (violations) meant to serve some physical bodily purposes for primary existence is transposed onto certain abstract categories. Life, Evolution, Universe…
I claim any species that does not indulge in an aware purposeful manipulation of the outside world would never ever ask a question concerning purpose of life!
The question in intimately connected with the ability to handle purposefully and to conceptualize it by means of an inherited language.
Your question is human. Nature may not be aware of it, operating as Nature does on an nonverbal plane. You may however project your purposefulness on it, and it may or may not reflect it. When it does reflect it you can consider yourself lucky! If it does not, you can just accuse the science of wallowing in a primitive stage or not possessing the rightful instruments.Or better still, seek your own answer, based on what life teaches you everyday, with and without instruments .. and may be help develop our knowledge of the universe in more than one dimension.
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Thank you Mushtaq, for writing your ideas, specially for giving time to think and to elaborate.
Your terminolgy reflects your knowledge/readings in a variety of fields. It was nice to know certain things about math.
You wrote :
“You may however project your purposefulness on it, and it may or may not reflect it. When it does reflect it you can consider yourself lucky! If it does not, you can just accuse the science of wallowing in a primitive stage or not possessing the rightful instruments.”
I feel to add:
When we seek answers by science, we get partial answers sometimes. When we do not find answers, there are limitations of our instruments,or of our knowledge and also sometimes there are limitations of our human brains. Perhaps sometimes we need to evolve our brains/thoughts further to find the answers of some questions. So, let our quest for knowledge continue with our evolution.
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