What Do Fossils Tell Us ?

[DE&i]

As I continue to use all the resources at my disposal i.e. literature and Thefossilforum.

My discussion question is:

- are we facing the next mass extinction? How rapidly might it occur (Compared to past mass extinctions)? Does it mean the end of the planet (i.e. do we need to "Save the World"), or can the planet take care of itself?

Regards,

Darren.

[tmaier]

My fossil tell me things... horrible things... but I've stopped listening to them.

Sorry, I just saw that opportunity and had to take it.

Really, the earth is an unstable place and you just have to accept that as an interesting fact. Of course we are facing the next extinction, but hopefully it will happen later.

[Troodon]

Fossils tells us that there have there always have been mass extinctions and the world has been on the brink several times and has always bounced back. The end has to happen sometime, so why worry. I would rather enjoy what we have and have fun with my fossils while time permits. Better to be an optimist than a pessimist makes going through life a bit easier.

Edited November 25, 2014 by Troodon

[Auspex]

From the perspective of a human's experience, the current rate at which the planet it losing species is pretty alarming, and not altogether surprising given man's impact on habitat. I am pretty confident, though, that the Earth, and life, will abide, and that 100.000 years from now it will be as amazing as it was 100,000 years ago.

[Taogan]

Whatever we do to the planet, good or bad won't make that much difference if you look at things with a geological time scale, the planet and life will survive. Extinction events happen on a regular basis the last thing I heard was that the next one was already overdue. Maybe it happened and I missed it.

[tmaier]

I'm kind of busy for the next three years, so I have tentatively penciled in mass extinction for late 2018. On a Tuesday...

[Ptychodus04]

According to endangeredspeciesinternational.org, 99.9% of all species that ever existed on Earth are extinct. Homo sapiens will enter that list at some point. We can speed the process but there's nothing we can do to "end the world". Life is a system that pays no mind to our puny species.

[Ptychodus04]

I'm kind of busy for the next three years, so I have tentatively penciled in mass extinction for late 2018. On a Tuesday...

Can we do it December 4th, 2018? That way I don't miss my birthday at the end of November...

[tmaier]

Homo sapiens will enter that list at some point.

Yes, that is why I have given up my citizenship in sapiens and joined the new species called Homo sapientior.

(Hint: Use google translate...)

[tmaier]

Can we do it December 4th, 2018? That way I don't miss my birthday at the end of November...

Yes, but I'm not getting up early, so let's make it about brunch time, OK?

[Ptychodus04]

That's great.

[Ludwigia]

The planet's been here for a long time and I think it'll still be here for at least a few billion years, barring a collision with something very large or the sun suddenly turning into a supernova. As to the human race, it's hard to say how long we survive and how we'll have developed in 100,000 years if we manage to last that long. Depends on how we behave, I guess. Maybe we'll be involved in the next mass extinction, but I wouldn't want to hazard a guess as to when that may be. I'm pretty sure I'll be celebrating my birthdays until my death day anyway.

Edited November 25, 2014 by Ludwigia

[Mediospirifer]

When the next mass extinction comes (there will certainly be one, we may be seeing it now), the Earth will survive. Life may be battered, but something will survive to evolve in the changed environment. Charismatic megafauna are likely to go extinct. That may include us, if we can't use our tool-using abilities and adaptability to mitigate things.

How fast it might occur I can't really address, but the ecological catastrophe caused by the Chicxulub impact at the end of the Cretaceous certainly was quicker. Keep in mind, though, that there were other things going on that may have contributed to that mass extinction (continental drift and massive lava eruptions in what is now India) that were longer in building. It's really hard to tell from the geological record just how long it took for any kind of extinction event to play out.

The kind of event that would be required to sterilize the Earth would be a nearby gamma-ray burst. Even that, deep-ocean and underground life (they've found chemotrophic bacteria 2 miles deep in mines!) might be shielded enough from the radiation to survive.

The one event that will eventually sterilize Earth will be when the Sun gets hotter. It's slowly warming as it ages, and will be 10% hotter in roughly 1 billion years. At some point, Earth will get too hot to sustain liquid water. I'd like to see the critter that can survive that!

What may destroy Earth completely will be when the Sun goes into the red giant phase in another 4-5 billion years. Astronomers have predicted that the Sun may ultimately swell to the size of the Earth's orbit! If it doesn't engulf Earth then, it will certainly burn it to a cinder, which may persist for tens of billions of years.

Of course, that's the long range prediction. I'm more concerned with the short term, and preserving the ecosystem that we currently have.

[tmaier]

You forgot to take into account what man himself is likely to do.

I was in the nuclear air force and on the one base I was at, we had more than 640 megatons of explosives to deliver. And we were just one of many. Termination of the planet was our job, and our motto was "We Deliver".

Those weapons still exist, but people don't talk about them anymore.

[jpc]

I find it amazing that folks on this forum are questioning when the next extinction will come... We are in the middle of it right now. It has been happening since European colonization of everywhere. Especially on islands... species just could not keep up with the change that humans brought... e.g. feasting on dodos. Right now, migratory bird numbers are declining in the western hemisphere, frogs and toads are dying off all over the world and we don't know why, global warming is likely to bring on some extinctions...primarily northern critters that can go no further north and high peak critters that can go no further up. Human population is only slowing down in a few places, mainly Europe, and more and more humans can only mean less and less animals. I am not a pessimist, I am a realist... not burying my head in the sand.

What does the fossil record tell us about mass extinctions? They do happen, and we have a hard time understanding why. We are watching one right now and have a hard time even seeing it.

[Carcharodontosaurus]

In 600 million years, the Sun will have gotten large enough to heat Earth to the point that 99% of plant species die out due to a decrease in CO2. 800 million years from now, all plant species will die off due to further decrease. In a billion or so years, the Sun will have expanded to the point that Earth's oceans will evaporate, though some water may remain in high-altitude areas and at the poles where microbes could survive. And there will definitely be life in caves and underground areas where it is cooler. A recent study (http://news.nationalgeographic.com/news/2013/10/131028-earth-biosignature-doomsday-space-science/) has given 2.8 billion years maximum for life to survive, at which point it will be so hot that DNA breaks down. In 5 billion years, the Sun will become a red giant and begin expanding rapidly, destroying Earth by 7.5 billion years.

Such topics are very interesting. I predict that tardigrades and fungi will be the last multicellular lifeforms. The Holocene extinction will be a tea party compared to the above.

Edited November 25, 2014 by Carcharodontosaurus

[jpc]

... yes, the Anthropocene Extinction.

[tmaier]

People only will only become wiser when they reach the brink of destruction. Until that time, things will proceed as normal. So... there is no use worrying about it because a priority is to have a good life while you can.

[tmaier]

A recent study (http://news.nationalgeographic.com/news/2013/10/131028-earth-biosignature-doomsday-space-science/) has given 2.8 billion years maximum for life to survive, at which point it will be so hot that DNA breaks down. In 5 billion years, the Sun will become a red giant and begin expanding rapidly, destroying Earth by 7.5 billion years.

The time from warning to detonation is 20 minutes.

Most people will not even hear the warning.

[Troodon]

Hey the world may last longer and be a better place if we become extinct

[painshill]

It’s a really big question they’ve given you – especially since some of the answers are to be found well outside the remit of palaeontology or even biology. You may have already found this website which is collating the evidence in support of the view that we are currently in an extinction event.

http://www.mysterium.com/extinction.html

I think it’s important to keep the frame of reference in mind… an extinction event is generally regarded as the loss of species at a rate which significantly exceeds the background level of extinction. Persistent and progressive but “gradual” loss that has no specific triggers isn’t quite the same thing… even if it’s large enough to qualify numerically as a mass extinction.

In the most general of terms, large extinctions have usually been the consequence of a short-term shock to a biosphere that’s already under long-term stress. If we look at past events, the triggers have variously been (in no particular order) supernovae, meteoritic/bolide impacts of various kinds, orbital tilt or magnetic reversals, volcanic activity and flood basalts, tsunamis, sea level changes, ocean anoxia, glaciations, climate change and overhunting. And usually it’s from a combination of two or more of those things.

Not only does that list represent a mixture of direct and indirect (consequential) causes, but it also represents (with our current level of technology) things which have varying degrees of predictability and mitigation. Whether or not extinctions are truly (or even approximately) periodic is still an uncertainty but there are nevertheless potentially things which we may see coming and be able to do something about. In addition, there are now other factors which may be self-inflicted. The possibility of a nuclear exchange between those who wield the power would not exist if everyone disarmed (although that’s pretty unlikely). Whether you believe in man-made “global warming” (more accurately “climate change”) or not – the effects are reversible up to an undetermined point of no return.

If an extinction event is coming our way then one thing we have to face up to (and haven’t yet) is that it’s likely to be unfair. Organisms occupying biological niches have traditionally suffered the worst, but humans as a species effectively no longer all occupy their environments on anything that resembles equality.

The thing that we haven’t faced up to is that a catastrophic event might be good for some areas (and people) but bad for others. There will be jealousies. There will be technological and financial differences in respective abilities to cope. How sympathetic might Russia, China or the Middle East be about the selective devastation of large parts of America by a megatsunami arriving from La Palma or the Yellowstone caldera blowing? What jealousies might be created if say the interior of Australia or Africa became lush verdant rainforest while Europe became a frozen mass or a dustbowl? How willing would countries with the ability to grow their food in test-tubes, desalinate their water or build domes/shelters with their own oxygen supply be to share what they have if they were hard-squeezed?

I think the ability of the planet to take care of itself is rather higher than it is given credit for by the “scaremongers”, but every bit of help we can give is probably not wasted effort. Man’s ability to take care of himself seems to be rather lower. It’s therefore worth bearing in mind that if we contribute to our own downfall then the history of extinctions is again that they aren’t fair. Removal of species is a contributor to evolution and advancement of those waiting in the wings to fill the gaps.

Edited November 25, 2014 by painshill

[tmaier]

Even though another global natural environmental catastrophe is an absolute certainty, the odds that we will destroy ourselves before that ever happens is more likely.

[tmaier]

I was thinking that maybe the reason SETI can't find any extraterrestrial signals is because it might be a normal path of civilization for technological creatures to destroy themselves shortly after their technology becomes advanced enough to allow it.

[Missourian]

I was thinking that maybe the reason SETI can't find any extraterrestrial signals is because it might be a normal path of civilization for technological creatures to destroy themselves shortly after their technology becomes advanced enough to allow it.

Or probably because they don't want to broadcast "hey, here we are!" to any potential galactic empires. More likely, ETs would have more deliberate means of communication.

[tmaier]

That's another possibility, we might be doing it in a very inefficient way.

Anyway, 30 years and not a peep out there.

Hello? Is this thing on?