Thread: THE END ?

Hi, I would just like to try and clarify something with the help of you people. I'm 50 years old now and in my time I've thought about lots of so called threats to the world i.e. NUCLEAR WAR - ASTEROID COLLISION - GLOBAL WARMING - GLOBAL COOLING - OVER POPULATION - have I left any out ? But am I correct in saying that these things will only preclude the exit of human life on this planet and not life itself ?

I'm asking because when I hear people say we must save the planet, they really must be saying lets save humankind on this planet. Am I correct ?

AND, a question if I may, if human life was wiped out by one of the above, could evolution repeat itself and produce the human all over again ?

BARCUD

Originally Posted by BARCUD

NUCLEAR WAR - ASTEROID COLLISION - GLOBAL WARMING - GLOBAL COOLING - OVER POPULATION -

You could add in a supernovae within twenty or thirty light years. A gamma ray burster directed at the planet. Unanticipated long term fluctuations in stellar output. Unanticipated short term solar output i.e. megaflares. Alien invasion (remember the Vogon constructor fleet. :wink: ) Destruction of biodiversity by human expansion - I suppose that could be a subset of overpopulation.

We could readily add a few more.

But am I correct in saying that these things will only preclude the exit of human life on this planet and not life itself ?

Not entirely. You are correct that it would take a much larger event to wipe out all life, but some of the above would be sufficient.
Supernovae, gamma ray bursters and a sufficiently large collision with another body could all eliminate all life. (Well, some deeply buried extremophiles could survive the last two, but a molten planet would sure eliminate even them.) Runaway greenhouse effect could turn the Earth into a close twin of Venus.

if human life was wiped out by one of the above, could evolution repeat itself and produce the human all over again ?

S.J.Gould, the noted palaeontologist, famously spoke of replaying the tape of life and coming up with a different result each time. In contrast Simon Conway Morris at Oxford believes that human like entities are the natural consequence of evolution on any Earthlike planet.

Personally, I don't think we have enough data yet to decide one way or another.

Ward and Brownlee have recenty proposed that biodiversity - with or without human intervention - has already peaked and that the Earth's biosphere is about to enter a long term decline into less and less biological complexity. (I don't want to reviwew their argument here, but it relates to the established increase in solar output and the carbon cycle on the Earth.) While this idea is provisional and unproven it suggests that if humanity were destroyed there is insufficient time for a comparable species to emerge before the decline in complexity sets in.

People want to save the planet so that their offspring will have a decent place to live, because they want to save their own families who are an extension of themselves, so really it all relates back to the individual and less to the human race as a whole, let alone all life on Earth.

But many individuals care little about doing the daily actions that will help to preserve the planet, precisely because as long it's ok while they themselves are living here, then why would they bother about generations in the far future?

Folk are contradictory, they are theoretically in favour of supporting ecological issues, but in practice they don't want to deprive themselves of comforts such as a car, or electronic equipment and gadgets, despite knowledge that they're polluting the atmosphere. Each says they're just one and therefore don't weigh much in the balance, but mass together all these 'just one' persons and you get the majority of people carrying on polluting day after day, yet denying responsibility. The delicate balance of Nature is regularly upset, often with no other aim than to line someone's pocket and fill up their bank account to the detriment of whoever or whatever - they care nothing for that.

Something drastic and unpredicted could happen at any time, but why waste time in speculation and why worry about it? What will that change? We can only do something about the dangers we know about in advance and nothing whatever about a worldwide catastrophe that strikes without warning.

If the human race were to be wiped out it would only matter to those humans alive at the time and only if they knew it was coming.

As for the atmosphere heating up to such temperatures that all major life forms would perish, it seems the one familiar creature with a very good chance of surviving is the cockroach. Just imagine that!

In response to the question whether evolution would reproduce a whole new set of humans - would we deserve another chance?