Human-generated extinctions

[DMB]

When I am feeling gloomy, I foresee us wiping out ourselves and a huge number of multi-cellular species by the unintended consequences of our burgeoning numbers and use of the planet's resources within a relatively short time.

It is already clear that many of the large mammal species are probably doomed.

But suppose that we don't manage to control global warming, how far down would the extinctions be likely to go? All the mammals? All the birds? What about the insects?

I find it hard to believe that anything we did could wipe out a significant number of bacterial species.

So what might the emergent evolutionary possibilities look like? Could intelligent life eventually reappear before larger forces finally zap the Earth?

[nygreenguy]

Heres a couple things to consider. Wetlands contains appx. ~50% of federally endangered animals and 35% of plants are located on wetlands which now only make up ~3.5% of the land. So, a large chunk of endangered wildlife is in an ecosystem which we are ,frankly, awful at managing and we simply wipe out without any thoughts.


Also, invasive species. Invasive species all around are taking over habitat critical for many plants (and some animals). Their lack of any natural predators or diseases allow them to drive out native species and they often create a homogeneous landscape.

the outlook is very very grim, HOWEVER, with good management it is still reversible.

As for bacteria, who knows. We know MAYBE 1% of the bacterial species out there. We simply lack the ability to gather and culture most kinds of bacteria to be able to study them.

[lpetrich]

So the only way they'll survive is if we treat their habitats as big zoos and aquariums.

Which is what is already happening, even if what we are doing is inadequate in some ways, and even if it is not called that.

[nygreenguy]

So the only way they'll survive is if we treat their habitats as big zoos and aquariums.Nope

Which is what is already happening,No its not
even if what we are doing is inadequate in some ways, and even if it is not called that.

Management =/= isolation.

[Coragyps]

DMB, if you can find After Man: A Zoology of the Future by Dougal Dixon, have a read. It's a fantasy of life 50,000,000 years after we kill ourselves off - and the rat lineage has come to prominence. The illustrations are great!

But it seems to be out of print...

[nygreenguy]

Wanted to add a few things. Firstly, extinction of charismatic mega fauna wont really have a large ecological effect. We need to keep an eye out on what are called "keystone" species. These are species which the local ecosystem strongly relies on. Take for example sphagnum moss. The destruction of this can eliminate a wetland ecosystem and everything in it. Same can go with muskrats. The elimination of them will drastically alter the plant comminity structure and all the shade intolorant species will be wiped out by the growth of typha (cattails) and phragmities (common reed).

[DMB]

I'm not suggesting that the extinction of large animals has the most ecological effect, but we look like flooding/desertifying large chunks of the planet just with climate change. As our numbers continue to go up in the short to medium term we shall be destroying all sorts of habitats just by taking them over.

I'm not so sure about rats. They have thrived in concert with humans. Whether they would do so well without us seems a bit doubtful.

I would have thought that with so many species of arthropods it would be hard to wipe out the lot, but in the end, I suppose bacteria/archaea are the only really certain survivors.

[Puck]

Many years ago, I thought that if we humans didn't exist, the rest of life would be so much better off. Seems like everything evolved in harmony, except humans. Somehow, when we took the leap of intelligence, we left being a natural part of the world, and ultimately, became not a parasite, but a cancer on the earth. The worst part is that we'll take all the parrots and fishes with us.

I think that if we wipe ourselves out, as opposed to an outside force, then there will be enough species left that it won't take too terribly long for new species to evolve to fill the gaps, and I think it will be the gaps that will be filled by newly evolved species. I hope nothing as 'intelligent' as we are would ever evolve again. Because we're pretty damned stupid in the big picture.

[nygreenguy]

Many years ago, I thought that if we humans didn't exist, the rest of life would be so much better off. Seems like everything evolved in harmony, except humans. Somehow, when we took the leap of intelligence, we left being a natural part of the world, and ultimately, became not a parasite, but a cancer on the earth. The worst part is that we'll take all the parrots and fishes with us.

I think that if we wipe ourselves out, as opposed to an outside force, then there will be enough species left that it won't take too terribly long for new species to evolve to fill the gaps, and I think it will be the gaps that will be filled by newly evolved species. I hope nothing as 'intelligent' as we are would ever evolve again. Because we're pretty damned stupid in the big picture.
Evolved in harmony? No way. How many species have naturally gone extinct? Yes, our intelligence gave us a HUGE advantage, but we never left the natural world, we simply found ways to manipulate it. We are not doing anything that anything else wouldnt do in our shoes. We are doing whats best for us. You talk about how great the world would be if we were not around, but how can something really be that great if no one is around to appreciate it?

[Puck]

Evolved in harmony? No way.

Yes, way. There's a pretty good balance in nature without us in the equation. I'm not making some fanciful claim that it wouldn't be brutal, ya know.


We are doing whats best for us.

Are you really sure about that? Wiping ourselves out doesn't seem very good for us. We have nukes capable of it, ya know. Changing the climate could be a little less than what's best for us. And there's that messy war shit we are so fond of.


You talk about how great the world would be if we were not around, but how can something really be that great if no one is around to appreciate it?

Oh, I think the other critters would like it just fine, and in many cases, more so, if we weren't here. I don't think there's a real need for human appreciation to make it good. It would be beautiful whether we were here, or not. Mind you, I'm happy to be here while I am, and I'll find pleasure gazing on the beauty until the day I die, but the world does not need me here.

[nygreenguy]

Yes, way. There's a pretty good balance in nature without us in the equation. I'm not making some fanciful claim that it wouldn't be brutal, ya know. There is no such thing as balance. If there was, we wouldnt have extinctions and speciation. Ecosystems are almost constantly in flux, disturbance occurs everywhere. Many species rely on a lack of this balance in order to thrive.



Are you really sure about that? Wiping ourselves out doesn't seem very good for us. We have nukes capable of it, ya know. Changing the climate could be a little less than what's best for us. And there's that messy war shit we are so fond of. Sure, but were no where NEAR wiping ourselves out. Screwing ourselves a bit yes, but not wiping out.



Oh, I think the other critters would like it just fine, and in many cases, more so, if we weren't here. I don't think there's a real need for human appreciation to make it good. It would be beautiful whether we were here, or not. Mind you, I'm happy to be here while I am, and I'll find pleasure gazing on the beauty until the day I die, but the world does not need me here. The world doesnt need you simply because it cant have such experiences. You are anthropomorphizing the planet/ecosystem.

If we dont kill the critters, then their predators will do the job for us. All organisms try to live, but that doesnt mean they "like" it.

[DMB]

There is no such thing as balance. If there was, we wouldnt have extinctions and speciation. Ecosystems are almost constantly in flux, disturbance occurs everywhere. Many species rely on a lack of this balance in order to thrive.
I'd agree with that. And the Earth has already seen some major extinction events, most of them providing opportunities for new species.

Sure, but we're no where NEAR wiping ourselves out. Screwing ourselves a bit yes, but not wiping out.
I don't see how you can be so sure. We could be quite easily progressing to a scenario where civilisation is lost and there is a huge collapse in human numbers. If the numbers get small enough we could be wiped out like any other marginal species.

[nygreenguy]

I don't see how you can be so sure. We could be quite easily progressing to a scenario where civilisation is lost and there is a huge collapse in human numbers. If the numbers get small enough we could be wiped out like any other marginal species.

We, unlike other species, dont need to rely only on our coat of fur to stay warm, or our legs to run fast. We are different than the other marginal species in our intelligence and our ability to adapt.

I simply dont see your scenario having much of a chance to come true (outside of massive meteor strike.)

[VoxRat]

... I simply dont see your scenario having much of a chance to come true (outside of massive meteor strike.)
I'm not sure if we're all talking about exactly the same scenario.
I agree it seems unlikely that the human population will go from 6,600,000,000 to zero in less than many thousands of years. But I don't think the probability of an order of magnitude collapse over the course of a few centuries is all that remote.

[Worldtraveller]

I don't think we'll kill off everything larger than us, necessarily. But there would probably be a trend towards smaller fauna for a while, based on the limited resources available.

Think about some of the larger species that are quite successful now, though, like coyotes, and a lot of birds that actually do better around human populations (pigeons, crows). They will probably be extremely successful in the short term, assuming a large human population decrease (or complete destruction of homo sapiens, even).

The loss of h. sapiens will probably have minimal impact on a large portion of the current existing species of insects and similar small critters like small birds and rats, mice, etc.

The warming of the oceans will have unpredictable impacts on large mammals, and I can see some cetaceans potentially doing better without humans hunting them.

But suppose that we don't manage to control global warming[.]
Some recent reports indicate that we've already passed the tipping point, and even if we stopped producing greenhouse gasses and did everything we currently know how to reduce them, we are looking at at least a century of effects and continued warming.

I agree with nygg in that I don't see h. sapiens as being completely wiped out. I think at the very least, there are some aboriginal populations in a few remote parts of the world that will barely notice the rest of us are gone.

[Puck]

There is no such thing as balance. If there was, we wouldnt have extinctions and speciation. Ecosystems are almost constantly in flux, disturbance occurs everywhere. Many species rely on a lack of this balance in order to thrive.

I think we are looking at it from different angles. I understand what you are saying and I don't disagree. I'm speaking more on a year to year scale, not taking into consideration large changes that impact life. In a year that is productive for rabbits, wolves will have more pups that survive to eat the extra rabbits. More insects, and you'll get more birds. They keep each other in balance that way. All life but human life tends to work this way. We have the brain power and opposable thumbs to alter the landscape artificially.

Sure, but were no where NEAR wiping ourselves out. Screwing ourselves a bit yes, but not wiping out.

I'm afraid I don't share your confidence. Honestly though, I think some humans will survive whatever befalls us, unless it's something like nukes or a comet.



The world doesnt need you simply because it cant have such experiences. You are anthropomorphizing the planet/ecosystem.

If we dont kill the critters, then their predators will do the job for us. All organisms try to live, but that doesnt mean they "like" it.

No, I am not anthropomorphizing the planet/ecosystem, nor the life upon it. But it is humans who disrupt migration routes and breeding grounds by building on it. It's humans who kill off the apex predators and then complain about so many deer that they move into people's yards and eat their plants. We've shoved the other animals off to the corners and into pockets, so they are isolated and become genetically too much alike. Of course they aren't going to have a critter party if we disappeared and do happy dances. But, they would be better off without us fucking about with the land, polluting the air and causing mayhem in general.

[Berthold]

Humans are euryphagous, and were already quite eurytopic with rather basic technology (Mousterian).

On the other hand, they are large, and have a slow generation turnover.

[Ray Moscow]

When I am feeling gloomy, I foresee us wiping out ourselves and a huge number of multi-cellular species by the unintended consequences of our burgeoning numbers and use of the planet's resources within a relatively short time.

It is already clear that many of the large mammal species are probably doomed.

But suppose that we don't manage to control global warming, how far down would the extinctions be likely to go? All the mammals? All the birds? What about the insects?

I find it hard to believe that anything we did could wipe out a significant number of bacterial species.

So what might the emergent evolutionary possibilities look like? Could intelligent life eventually reappear before larger forces finally zap the Earth?

Basically all the large mammals are toast. The main problem with that is that we are large mammals, also, and could easily go the way of the wooly mammoth or Neanderthals.

I don't think anything we do is going to wipe out all the invertebrates, though. The roach will look down upon our remains and laugh, or rather would if it had much of a brain.

[premjan]

Tuataras have the highest rate of molecular evolution - maybe they will fill the gap.

[David M]

Look on the bright side, at least no single human family has been solely responsible for the extinction of a species.

The Stephens Island wren (Xenicus lyalli) was both discovered and exterminated by a single pregnant cat and its offspring that escaped onto the island in early 1894, 1 year later no trace of the species could be found.

[Berthold]

Look on the bright side, at least no single human family has been solely responsible for the extinction of a species.
It may have happened, however; settlers of certain islands may have consisted of one clan.

[Sodong]

Here's my candidate (http://images.google.ca/imgres?imgurl=http://www.biology-blog.com/images/blogs/7-2006/desert-rodent-551.jpg&imgrefurl=http://www.biology-blog.com/blogs/permalinks/7-2006/coexistence-among-desert-rodents.html&usg=__EE8UTg6dcmQhdwULpQ_HxFF2EB4=&h=207&w=312&sz=12&hl=en&start=1&tbnid=zc9kZ6nZGi0bXM:&tbnh=78&tbnw=117&prev=/images%3Fq%3Ddesert%2Brodents%26gbv%3D2%26hl%3Den) for surviving any environmental/economic/social collapse that might cause human depopulation on a large scale.

[SteveF]

I think we are looking at it from different angles. I understand what you are saying and I don't disagree. I'm speaking more on a year to year scale, not taking into consideration large changes that impact life. In a year that is productive for rabbits, wolves will have more pups that survive to eat the extra rabbits. More insects, and you'll get more birds. They keep each other in balance that way. All life but human life tends to work this way.

When NYGG talks of disturbance, this isn't something that just occurs on long timescales, it's a vital part of ecosystem functioning on pretty much all scales, short and long, small and big. By way of example, check out the Intermediate Disturbance Hypothesis:

http://en.wikipedia.org/wiki/Intermediate_Disturbance_Hypothesis

This hypothesis is far from flawless and can't be generalised everywhere, but it does speak to the importance of disturbance.

[4321lynx]

There is a difference between disturbance of any magnitude & the absolute fuckup caused by humans.

[nygreenguy]

There is a difference between disturbance of any magnitude & the absolute fuckup caused by humans.

So you are saying the comet that hit and wiped out 90% of all life isnt as bad as what we have done??!

[Ray Moscow]

There is a difference between disturbance of any magnitude & the absolute fuckup caused by humans.

So you are saying the comet that hit and wiped out 90% of all life isnt as bad as what we have done??!

As far as species diversity is concerned, we're pretty much just a slow-acting giant meteor.

[nygreenguy]

There is a difference between disturbance of any magnitude & the absolute fuckup caused by humans.

So you are saying the comet that hit and wiped out 90% of all life isnt as bad as what we have done??!

As far as species diversity is concerned, we're pretty much just a slow-acting giant meteor.

Oh no. Meteors are GREAT for diversity. Sure, they wipe everything out, but that frees up countless niches which drive evolution. For us, its more of the opposite. When we destroy habitat (excluding fires) it tends to become more homogeneous.

[TheBear]

So what might the emergent evolutionary possibilities look like? Could intelligent life eventually reappear before larger forces finally zap the Earth?
Given that the sun is about half-way through it's life cycle, we're talking about that possibility occurring within the next 5 billion years. It happened at least once within that same time span, so, we know it's possible.

[Berthold]

Given that the sun is about half-way through it's life cycle, we're talking about that possibility occurring within the next 5 billion years.
More likely, the time remaining is considerably less.

These new theories of stellar development are relatively recent (came after what Carl Sagan based his Cosmos series on): Stellar luminosity increases slowly already while a star is on the main sequence. Hospitability of Earth is estimated to last for only another 500 million years. I don't know the original publications, but Ward and Brownlee ("The Life and Death of Planet Earth") take this estimate as current knowledge.

[epepke]

When I am feeling gloomy, I foresee us wiping out ourselves and a huge number of multi-cellular species by the unintended consequences of our burgeoning numbers and use of the planet's resources within a relatively short time.

Yeah. That thought always cheers me up, too.