h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

inbetween ofcourse. but that goes for everybody .1 day your alive .1 day less to live .

The virus, not the person. Is the virus alive?

yeah its a living organism why ?

But it's not alive. That's the thing.

Biologists accept that viruses are not alive because they do not have their own metabolism, and they are just way too simple. They hijack cells replication machinery to reproduce. A minority disagree.

Are Transposable Elements alive? These are stretches of DNA that like to replicate themselves around the genome. 'Jumping Genes' they're called. These can be seen as the precursors to viruses, but no-one thinks these guys are alive. The only difference between TEs and viruses is that a viruses' tiny genome (4 or so genes) contains a gene that encodes for a protective protein coat that goes around the DNA.

As I said, life is hard to pin down.

Ste

<>

Nice one ~jwf~ I like that concept too.

As well as Ictoans statement about fire, I also like the one about mountains, in that we can't percieve mountains as being 'alive' as such because we are in such a limited time frame.

how do they hijack cells without being alive? its imposible

Yes a definition of life is hard to pin down, ste but isn't it fun trying... yays

There is no baboon There is no baboon There is no baboon There is no baboon There is no baboon There is no baboon There is no baboon There is no baboon

leave off

Yeah, it is vixen

Baboon, with the use of enzymes. All they need is an enzyme or two that'll copy it's DNA, one or two to make it's protein coat, and there you go. These are encoded in it's genes.

Why is it impossible? There are many scientific experiments that use enzymes to do tasks. They're not alive are they?

Ste

im not into all this stuff as you can guess .my thinking is simple when something is alive its alive when its dead its dead .

Fair enough, I'm a biologist and I am into it. What I'm trying to say is that when you get down to it, the differences between life and non-life get pretty blurry. It's not as simple as what common sense dictates...

Ste

ok agreed but how significant is it then?

I'm sorry, how significant is what?

i was chatting about human life about ending when you die. then you say life aint so black and white .does this have any significance.

<>



My point of view is that life is, a succession of energy-producing electro-chemical processes by a naturally occurring,
(simple or complex) organism composed of a combination of molecules, each consisting of carbon, hydrogen, and oxygen atoms, and a few other elements, forming cells, but not exclusivly.!
which consume 'food' and produce 'waste' in the process called metabolism;

The organism is capable of living within the environment without dependency on any other organism,energy use is manifest by growth with size limits for the most.self-healing, possibly movement, self-replication with each offspring slightly different,capable of modifying their living environment, both beneficially and detrimentally, with eventual termination of energy production,

Exceptions beeing egg, sperm, spore, seed, which do not consume food and produce waste;
and are replication structures,

Baboon,

I was more talking about the original question posed, but to answer your question I would say a human life has ended when its metabolism (a fancy way of saying biochemical reactions that support the functions of life) has shut down. We tend to think of a human life as the person and the personality that are somehow contained within the brain. Something most cultures would agree upon. So, when the brain's metabolism ceases then that person has died.

That's my take on things anyway.


A Dent,

'... life is a succession of energy-producing electro-chemical processes by a naturally occurring, (simple or complex) organism composed of a combination of molecules, each consisting of carbon, hydrogen, and oxygen atoms, and a few other elements'

But not all life's reactions produce energy. Not all of them are *electro*-chemical. One day soon it's concievable that biology might make an artificial life-form, doesnt have to be natural. Life can also be silicon-based, theoretically...

'The organism is capable of living within the environment without dependency on any other organism...'

That doesn't happen, we're all intertwined in ecosystems. What of parasites?

'energy use is manifest by growth with size limits for the most... self-replication with each offspring slightly different...'

Bacteria remain pretty much the same size, and are clonal and asexual in nature. Descent with modification is very important in evolution though.

This is fun

Ste

hi Ste,

I forgot you asked me about some interesting threads - I should have known you'd like this one.

<>

Does this mean that there is no final and clear definition?

az

Life [Na na na, na na] Life is Life [Na na na, na na]

[Well, according to some German electropop lot from the 80's]

I knew someone would post that song! guess what I will be singing for the rest of the day?

"The organism is capable of living within the environment without dependency on any other organism"
That's us humans stuffed then, we couldn;t survive without the thousands of organisms (bacteria and stuff) we use to break down our food and so forth.

I do find it interesting that nearly everyone includes the ability to replicate, beit through cloning, being it through partnered sex or whatever, as a requirement for life. But this, as shown earlier, is not the case. Things can be alive and yet unable to replicate. Interesting we place so much emphasis and value on our ability to produce off spring.