Thread: Biological life and death ?

Hi guys, I hope I'm correct in saying biology deals with those things that 'live' ? If so, then does biology also deal with everything that dies ?

I ask the question because I was wondering why in fact living things die ? Why don't living things just carry on living ?

BARCUD

Originally Posted by BARCUD

Hi guys, I hope I'm correct in saying biology deals with those things that 'live' ? If so, then does biology also deal with everything that dies ?

I ask the question because I was wondering why in fact living things die ? Why don't living things just carry on living ?

BARCUD

Organisms die for a number of reasons. You can see death as a function of evolution. without a cycle of reproduction and death, there is no way life can sufficiently adapt to changing environments. Our genes do not die, they change bodies (and thus change the genes they travel with) over generations and that ensures their long term survival. Death also limits the extent of organisms' competition for resources with their own offspring. Organisms could be effectively immortal but overpopulation would result in their mass deaths if they were also capable of reproduction. Take away reproduction and you take away variation.

That's a question that a lot of people have asked, Barcud. The answers are still not completely clear, but in my opinion the reasons are generally tied to this: at some point, the cost of maintaining your body becomes greater than any benefit you would gain in further reproduction. At that point you stop investing energy in self maintenance, and you die.

Researchers have done work with fruit flies, prevented females from mating until an advanced age. After several generations of this, the lifespans of the fruit flies were several times longer than they were in the first generation. So at least in the case of fruit flies, their bodies make sure to maintain themselves until the time that they can expect to reproduce.

Hi guys, I was surprised to read that death is something to do with evolution !? It's like saying if nobody died then the planet would be overun with humans and consequently humankind would cease to exist. SO, somehow our biological genes are aware of this and so the human life is cut accordingly. Have I got that correct ?

I guess just plain old wear and tear exhausts our genes to a point where they can no longer operate at their optimum level is another option, if I read your posts accurately.

This might be totally irrelevent BUT, let's say biological life on this planet does cease to exist, then the planet would still be here. Just like most of the other planets. Is there a name for this other life ? the non biological life of the solar system ?

Hope that doesn't take us too far from my original thread.

BARCUD

Hi guys, I was surprised to read that death is something to do with evolution !? It's like saying if nobody died then the planet would be overun with humans and consequently humankind would cease to exist. SO, somehow our biological genes are aware of this and so the human life is cut accordingly. Have I got that correct ?

I guess just plain old wear and tear exhausts our genes to a point where they can no longer operate at their optimum level is another option, if I read your posts accurately.

This might be totally irrelevent BUT, let's say biological life on this planet does cease to exist, then the planet would still be here. Just like most of the other planets. Is there a name for this other life ? the non biological life of the solar system ?

Hope that doesn't take us too far from my original thread.

BARCUD

Originally Posted by BARCUD

Hi guys, I was surprised to read that death is something to do with evolution !? It's like saying if nobody died then the planet would be overun with humans and consequently humankind would cease to exist. SO, somehow our biological genes are aware of this and so the human life is cut accordingly. Have I got that correct ?

I guess just plain old wear and tear exhausts our genes to a point where they can no longer operate at their optimum level is another option, if I read your posts accurately.

This might be totally irrelevent BUT, let's say biological life on this planet does cease to exist, then the planet would still be here. Just like most of the other planets. Is there a name for this other life ? the non biological life of the solar system ?

Hope that doesn't take us too far from my original thread.

BARCUD

Here's where the so-called gene's-eye-view can help.

From the point of view of an individual organism, death cannot be of any evolutionary assistance since it means the death of the organism.

From a species point of view too, death cannot help because invariably, through genetic drift and otherwise, the species dies.

From a gene's point of view, however, reproduction ensures (or increases the probability of) the survival of the gene (or the information it encodes), and it will be to the gene's advantage to associate only with other genes that do not assist in survival of the phenotype (the organism) indefinitely, and therefore in competition with fresher phenotypes less beset by parasites and injury.

I've tried to be succinct here, but if there's anything regarding which you'd like further explanation or explication, feel free to ask.

cheer

shanks

PS. We define life (as we know it) as cellular. If life ceased to exist, therefore (and from a Weak Anthropic Pinciple point of view, if we ceased to exist in particular) then there would be no point talking about the universe as another 'form' of life: it's just stretching the meaning of the word too far from its normal use.

Originally Posted by BARCUD

This might be totally irrelevent BUT, let's say biological life on this planet does cease to exist, then the planet would still be here. Just like most of the other planets. Is there a name for this other life ? the non biological life of the solar system ?

Hope that doesn't take us too far from my original thread.

BARCUD

We define life by some pretty strict criteria. The line is drawn somewhere before viruses. Chemical reactions are not life and the mere stability of matter, though they are its basis. "Survival of the fittest" in terms of genes is in fact just an extension of what I think of as "persistence of the stable" in non-life matter.

When life started, the forms that replicated had a better chance of survival. That is because they rapidly could adapt to the environment.

Anything that doesn't replicate just has to sit any environmental change or stress out.

Naturally this gave the fast replicators an advantage over forms that hardly ever replicated.

And that is why we die.

We descent from an ancient line of life that specialized in death. So that there will be life.

Hi guys, thanks for the input. Could I now answer the question 'why do living things die' ? erm, nope ! I have great difficulty with understanding technical words and terms. My brain for some reason only works in pictures and diagrams. It seems without these I'm bloody hopeless ! And of course I am seeing a heck of a lot of words I have never seen before that hampers my understanding too.

BUT, don't give up guys, some of it does make sense

BARCUD

the reason why living things die is the same reason that your car ultimately has to go to the scrap heap : it wears out until it becomes cheaper to buy a new car rather than to keep on repairing the old one

Ah ha, that sometimes works ! Replacing the picture of confusion in my head with a picture I am more familiar with.

We have classic cars that have been kept alive for well past their normal life.

SO, is there anyway that genes can be regenerated OR kept alive longer than they normally would ?

BARCUD

those classic cars have been kept alive by treating them ever so gently, but also by not placing many demands on them - don't expect them to go from 0 to 60 in 5 seconds flat or drive around the world in 80 days

in fact that's what often happens with living creatures : the ones that protect themselves from predation AND live in the slow lane live longest - tortoises are the living proof of that (until man came along an thought they would make wonderful soup)

Originally Posted by BARCUD

Hi guys, thanks for the input. Could I now answer the question 'why do living things die' ? erm, nope ! I have great difficulty with understanding technical words and terms. My brain for some reason only works in pictures and diagrams. It seems without these I'm bloody hopeless ! And of course I am seeing a heck of a lot of words I have never seen before that hampers my understanding too.

BUT, don't give up guys, some of it does make sense

BARCUD

That's why they invented dictionaries. You look up words you don't understand and expand your language skills in this manner.

With modern technology this has become even easier. You just copy paste the word and add it to the search box of an online dictionary.

such as:

http://dictionary.reference.com/search?q=gobbledegook

Originally Posted by BARCUD

Hi guys, thanks for the input. Could I now answer the question 'why do living things die' ? erm, nope ! I have great difficulty with understanding technical words and terms. My brain for some reason only works in pictures and diagrams. It seems without these I'm bloody hopeless ! And of course I am seeing a heck of a lot of words I have never seen before that hampers my understanding too.

BUT, don't give up guys, some of it does make sense

BARCUD

You're asking for an answer in terms of biology. We've given you several. They're not written in very technical language.

The summary of my argument was that you can have eternal life or reproduction, but not both. If you have both, you get massive overcrowding and resource competition. If you just have eternal life, you have no means to change relative to your environment. So we have death and reproduction which allows us to change from generation to generation as well as maintaining our numbers at a reasonable level.

Hi, dictionaries? I've been reading quite a bit, all biology based books, and some of the books have a glossary in the back, great ? erm, not so great sometimes. A lot of the glossary definitions still take it for granted you have a certain grounding in the subject and it's still not clear. The other day I was in a big book shop and I thought I would get a biology dictionary. When I looked through them, some definitions were still unclear to me, AND some definitions didn't quite say what the glossary's say ! As a consequence I get even more confused :?

To tell you my background, I'm not exactly dim, I have a degree/certificates in theology, child psychology, sociology, philosophy and a B.ed teaching degree, so I'm familiar with tackling words and technical terms. BUT, when it comes to maths/numbers, sciences, I go completely blank. I remember getting clobbered across the head by the science teacher because he thought I was taking the piss, when really it just wasn't sinking in ! Many have tried and failed with me. And let's face it, at 50 yrs old it gets incresingly difficult to learn. What's the saying, 'you can't teach an old dog new tricks' !?

quote :
The summary of my argument was that you can have eternal life or reproduction, but not both. If you have both, you get massive overcrowding and resource competition. If you just have eternal life, you have no means to change relative to your environment. So we have death and reproduction which allows us to change from generation to generation as well as maintaining our numbers at a reasonable level.

Thanks, now that tells me the way it is. BUT, how do our genes know that ? (another saying for you, 'patience is a virtue', and I'm hoping you are virtuous)

BARCUD

Thanks, now that tells me the way it is. BUT, how do our genes know that ?

Not sure if this point has been made already, but the death and reproduction cycle probably evolved pretty early on, with the effect that all multi-cellular and most uni-cellular life using this strategy (AFAIK). Early forms that were immortal, with or without reproduction, inevitably died out as has been explained. So while it might look like "our genes know that", it is merely another consequence of evolution.


Edit: Found a good site (at least at first glance)

http://www.senescence.info/nature.html

Edit 2: After reading the link, it does not seem as simple as I had thought. Longevity and viable reproduction is still dependant on environment though, in that a balance is achieved pretty quickly when a new nich is exploited. There are many animals that easily outlive us.

Our genes don't know shit.

But they evolved in a system where rapid replication was succesful.

Anything that didn't die never evolved.

They went extinctomento.

dead.

as a dodo.

We are the product of our evolutionary history. You cannot change what was essential to the system: replication and modification with each round of replication.

It made us what we are.

Death is birth, birth is death.

Originally Posted by BARCUD

quote :
The summary of my argument was that you can have eternal life or reproduction, but not both. If you have both, you get massive overcrowding and resource competition. If you just have eternal life, you have no means to change relative to your environment. So we have death and reproduction which allows us to change from generation to generation as well as maintaining our numbers at a reasonable level.

Thanks, now that tells me the way it is. BUT, how do our genes know that ? (another saying for you, 'patience is a virtue', and I'm hoping you are virtuous)

BARCUD

When we talk about genes knowing things or doing things, we are merely anthropomorphising for convenience. Genes have no thoughts, no intentions, no knowledge. Ditto evolution and death. They're just processes, chemical reactions on a grand scale. As well to ask how fire knows when to die when its fuel runs out. It does not, it simply ceases to be.

Organisms that attempted to live forever with reproduction died out due to overcrowding/ lack of food etc. Those that attempted to live forever without reproduction, did not change when their environments changed and also died out. So any time such characteristics emerged, those genes were selected against by evolution. Again, this is not an active process, they simply failed to survive long enough to reproduce. So today we have no organisms descended from those guys.

BIOLOGISTA, could you please explain this sentence ?

'we are merely anthropomorphising for convenience'

thanks, BARCUD

Originally Posted by BARCUD

BIOLOGISTA, could you please explain this sentence ?

'we are merely anthropomorphising for convenience'

thanks, BARCUD

This means that we pretend that genes behave as if alive or conscious when they are in fact mindless. Anthropomorphism is the act of giving human characteristics to something which is not human. In this case, we are doing so knowing that it is not technically correct, but makes explaining some of the behaviour of genes easier for people to understand. Mind you, the cost of that is that some may come to take that literally.