is darwin's natural selection theory only caused by mutations? Watch

dinosaur711
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does natural selection take place only because of desirable mutations in animals which makes them better adapted and therefore able to survive and go on to breed OR can natural selection take place due to "ACQUIRED characteristics" ?
any help would be really appreciated- and please quote me so i know that you've replied! thank you !
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Hedgehunter
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Its only down to random mutations..those with rubbish mutations die, those with desirable mutations survive to reproduce.
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CommunistHamster
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Acquired characteristics aren't passed on to their offspring, so yes, it's only due to genetic mutations.
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figureeight
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(Original post by dinosaur711)
does natural selection take place only because of desirable mutations in animals which makes them better adapted and therefore able to survive and go on to breed OR can natural selection take place due to "ACQUIRED characteristics" ?
any help would be really appreciated- and please quote me so i know that you've replied! thank you !
I posted this somewhere else, but here:

(Original post by figureeight)
Ok, the premise of his theory is that the creatures (all types of complex organism; flowers, animals, insects, everything) have mutated over time from more simplistic creatures. That is to say that all creatures share a common ancestor, and have diverged from there on. This is down to purely naturalistic descent with modification, ie. we evolved in a random process due to modifications in our genes.

The good modifications are kept because they help us survive (this is called natural selection) and the bad modifications will often lead to the organism being weaker or more vulnerable, thus making it less likely to proliferate (ie. it gets eaten, dies, can't reproduce, etc. therefore we get no more of the same bad gene modification from that organism).

Once the good modificatins are kept, the offspring will also inherit that good gene modification because its parents will have benefited from it, and therefore animals grew wings, because they didn't get eaten so quickly, and then their offspring grew wings because their parents were still alive, whereas the land animals that didn't grow wings were 'granted' with another type of defense like they had shells, and then their offspring survived because of it. The predators grew bigger teeth and stronger jaws and faster legs to counter this, etc. On the other hand, the animals that either didn't evolve or were unlucky and whose skeleton was thinned or who had eyes that pointed upwards and not forwards (yeah, its hypoerbole, but you get the point) were more likely to die.

Over many years, this resulted in humans ... and a whole bunch of other highly evolved and perfected creatures.
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dinosaur711
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thanks everyone
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Formica
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(Original post by dinosaur711)
does natural selection take place only because of desirable mutations in animals which makes them better adapted and therefore able to survive and go on to breed OR can natural selection take place due to "ACQUIRED characteristics" ?
any help would be really appreciated- and please quote me so i know that you've replied! thank you !
Natural selection is due to inherited variation within a population, and the variation is caused by mutations. I think what you mean to ask is if these inherited variations can be from aquired characteristics, to which the answer is no.
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Nehustan
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Natural selection in micro occurs due to mutations which when become expressed at the macro (i.e broad expression within breeding population) may lead to an 'evolution' of the population, but these mutations can happen in a 'non-linear' way, i.e. years/decades/centuries prior to it having environmental relevance. For instance an expression of a gene may seem to be neutral, neither deleterious or advantageous in a particular environmental niche, but may then go on to be 'preadaptive', i.e. its expression in a particular niche proves advantageous.

Sometimes even deleterious gene expression can be advantageous. Look at sickle cell, it gives a very interesting perspective on natural selection.
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dinosaur711
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(Original post by Nehustan)
Natural selection in micro occurs due to mutations which when become expressed at the macro (i.e broad expression within breeding population) may lead to an 'evolution' of the population, but these mutations can happen in a 'non-linear' way, i.e. years/decades/centuries prior to it having environmetal relevance. For instance an expression of a gene may seem to be neutral, neither deleterious or advantageous in a particular environmental niche, but may then go on to be 'preadaptive', i.e. its expression in a particular niche proves advantageous.

Sometimes even deleterious gene expression can be advantageous. Look at sickle cell, it gives a very interesting perspective on natural selection.
you should write for wikipedia hee hee.. in anycase thank you!
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Nehustan
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(Original post by dinosaur711)
you should write for wikipedia hee hee.. in anycase thank you!
Pleasure...what do you want to go on and study???
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dinosaur711
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(Original post by Nehustan)
Pleasure...what do you want to go on and study???
umm something chemi/bio related.. i'm not really sure actually- zoology/pure chemistry/medicine...??? you @ uni?
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Nehustan
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(Original post by dinosaur711)
umm something chemi/bio related.. i'm not really sure actually- zoology/pure chemistry/medicine...??? you @ uni?
Very interesting subjects. I didn't do Biology at school, I took Physics and Chemistry; I even recall during options a mate said 'Are you doing Biology?', to which I replied 'Boy meets girl, that's all the Biology I need to know'. Quite a few years later I find I have just finished a BSc in Anthropology with roughly half of my degree being in biosciences, shows what I knew at 14 I suppose :P

That said much of the biology I have taken during my course has been helped by my Chemistry. When we looked at DNA and its chemical basis, it really helped me get a grasp on how it was structured and how recombination physically worked.
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SmellyCat16
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survival of the fittest ----> survive then go on to reproduce because they are best adapted
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dinosaur711
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(Original post by Nehustan)
Very interesting subjects. I didn't do biology at school, I took Physics and Chemistry; I even recall during options a mate said 'Are you doing Biology?', to which I replied 'Boy meets girl, that's all the biology I need to know'. Quite a few years later I find I have just finished a BSc in Anthropology with roughly half of my degree being in biosciences, shows what I knew at 14 I suppose :P

That said much of the biology I have taken during my course has been helped by my Chemistry. When we looked at DNA and its chemical basis, it really helped me get a grasp on how it was structured and how recombination physically worked.
cool lol
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Nehustan
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(Original post by SmellyCat16)
survival of the fittest ----> survive then go on to reproduce because they are best adapted
I can't recall which species it is (but have a feeling it may be Gorillas..perhaps some type of chimp) where the alpha male is 'outwitted' by a male lower down the hierarchy. If there are any 'geeks' reading, always recall in the context of H. sapiens, when confronted by 'jocks', survival of the sneakiest/smartest may also apply
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dinosaur711
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(Original post by Nehustan)
I can't recall which species it is (but have a feeling it may be Gorillas..perhaps some type of chimp) where the alpha male is 'outwitted' by a male lower down the hierarchy. If there are any 'geeks' reading, always recall in the context of H. sapiens, when confronted by 'jocks', survival of the sneakiest/smartest may also apply
heyy sorry to bug you with another stupid question it's just i'm having to teach my biology gcse to myself which is tomorrow do you know ho fossils are made in terms of "minerals replacing harder parts in an animal" huh? me=stupid
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Nehustan
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(Original post by dinosaur711)
heyy to bug you with another stupid question it's just i'm having to teach my biology gcse to myself which is tomorrow do you know ho fossils are made in terms of "minerals replacing harder parts in an animal" huh? me=stupid
I think the correct term for fossilisation is 'calcification', where the organic matter is replaced by calcium through time. Check on that tho'.
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Nehustan
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(Original post by Nehustan)
(Original post by dinosaur711)
heyy sorry to bug you with another stupid question it's just i'm having to teach my biology gcse to myself which is tomorrow do you know ho fossils are made in terms of "minerals replacing harder parts in an animal" huh? me=stupid
I think the correct term for fossilisation is 'calcification', where the organic matter is replaced by calcium through time. Check on that tho'.
Found this, should be of some help...
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dinosaur711
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(Original post by Nehustan)
I think the correct term for fossilisation is 'calcification', where the organic matter is replaced by calcium through time. Check on that tho'.
thl:pizza: here have a pizza for all your help.
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ixivxivi
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(Original post by CommunistHamster)
Acquired characteristics aren't passed on to their offspring, so yes, it's only due to genetic mutations.
ACTUALLY, something fabulously cool called epigenetics might have evidence against that . This is all about how genes can be differently expressed, regardless of the genetic material present (so clones can be different. This is what is behind the fact that if you were to clone a tortoise shell, it's clone would NOT be identical in apperance! I'll get onto that later). There's incredibly interesting stuff saying that the diet of a mother (mouse) while can effect the way in which her offspring's DNA is packaged (generally, the more tightly packaged and harder to access a gene is, the less likely it'll be active, and vice versa) which can alter their characteristics such as coat colour.

And epigenetic effects are often conserved from generation to generation (although I'm still ignorant of the mechanism of this - epigenetic effects are usually centred around modifications of the histones (proteins that the DNA in eukaryotes' nuclei is wound around) to make them have more or less affinity for DNA (e.g. so that they are more negatively charged, so more likely to repel the negatively charged DNA, making the DNA less tightly bound and so more likely to be accessably by the cell's transcription machinery and more likely to have genes on it be expressed) and of the DNA, and I'm ignorant of how these are propagated during DNA replication, although I am assured that they are). Hence the granddaughter's of the original mouse mother that ate a particular diet might be phenotypically effected by that very fact. Hence all passed on characteristics are not nessecarily coded in the DNA sequence. This is all pretty cool because it gives a direct example of enviroment affecting genetics.
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ixivxivi
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As for tortoise shell cats, the reasoning behind them is that they are female. And hence have two X chromosomes. If both of these were allowed to express the proteins they code, the females would have an excess of these proteins, compared to the males (Y chromosomes are kinda just crappy, messed up versions of the X :p:). Hence in all female cells (except from gametes), one of the 2 X chromosomes is inactivated (and called the Barr body). Since this is done at random, if you have two different alleles of a gene in your X chromosomes, you get a mosaic expression of this gene (the inactivation of a X chromosome is at random to either of them). Tortoise shell cats have a different coat colour allele on its two X chromosomes, hence the colour pattern of their coat is determined by the random inactivation of X chromosomes. However, clones (I think you need to remove all the epigenetic inactivation of chromos etc away for a successful cloning. I do not know how this is done) would have a different random distribution of inactivated X chromos and so a different coat pattern.

Not entirely relevant to the Q asked, but interesting nontheless (although possibly not that well explained )
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