Are you an Optimist or Pessimist?

[Darwinsbulldog]

@ owheelj

WTF?

Post #36!

Coxall, H. K., S. D'Hondt, et al. (2006). "Pelagic evolution and environmental recovery after the Cretaceous-Paleogene mass extinction." Geology 34(4): 297-300.
D'Hondt, S., P. Donaghay, et al. (1998). "Organic Carbon Fluxes and Ecological Recovery from the Cretaceous-Tertiary Mass Extinction." Science 282(5387): 276-279.
Jablonski, D. (2002). "Survival without recovery after mass extinctions." Proceedings of the National Academy of Sciences 99(12): 8139-8144.
Payne, J. L., D. J. Lehrmann, et al. (2004). "Large Perturbations of the Carbon Cycle During Recovery from the End-Permian Extinction." Science 305(5683): 506-509.
Sahney, S. and M. J. Benton (2008). "Recovery from the most profound mass extinction of all time." Proceedings of the Royal Society B: Biological Sciences 275(1636): 759-765.
Solé, R. V., J. M. Montoya, et al. (2002). "Recovery after mass extinction: evolutionary assembly in large–scale biosphere dynamics." Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 357(1421): 697-707.
The bolded refs are fully downloadable.

It seems you are not familiar with any of these refs, or have bothered to read them, so I am not going to bother posting them any more. If you don't know some of the basic material there is no point going on with this discussion.

[Centauri]

He does like the sound of his own voice.

[owheelj]

Originally Posted by Darwinsbulldog

@ owheelj

WTF?

Post #36!



It seems you are not familiar with any of these refs, or have bothered to read them, so I am not going to bother posting them any more. If you don't know some of the basic material there is no point going on with this discussion.

Sorry, actually I did have a look at some of them when you posted, but had forgot about them when you talked about "refs" and didn't look past that page. I don't know why you assume I'm not familiar with the "basic material." Nor can I see anything I've said that's contradicted by any of those - I have access to all of them. Again they're indicating that things would be bad, but they're not indicating that humanity would go extinct in a K/T sized extinction.

[owheelj]

Originally Posted by Centauri

He does like the sound of his own voice.

Biological responses to stochastic disturbances is a major component of what I study.

And there's another piece of evidence in favour of human prevalence through a mass extinction. In Tasmania we've experienced a geologically rapid cycle of ice ages. Plants response to these events is loosely broken into two types - "fast evolvers" and "tolerators." Looking at the fossil record over time (I imagine the references are the large series of papers GJ Jordan from Utas, who took us in the third year subject where we covered this relationship), we see that the "fast evolvers" had a very high extinction rate because the speed of change at each glaciation and warming was faster than their rate of evolution. On the other hand, the species that evolved much slower, but could tolerate a much wider range (we could also call them "generalists") survive to today. This supports evidence from other large disturbances - that generalists do far better than specialists. Humans have the broadest environmental range of any terrestrial vertebrate, macrofungi, or plant on Earth (and probably the broadest range of any multicellular organism). We have the broadest diet on the planet. To say that the animal that eats the widest range of foods and survives in the widest range of environments would go extinct, surely implies that all the plants and animals that have a smaller niche would also go extinct, which must mean we're talking about an extinction much larger than the dinosaur extinction.

[Darwinsbulldog]

Originally Posted by owheelj

Sorry, actually I did have a look at some of them when you posted, but had forgot about them when you talked about "refs" and didn't look past that page. I don't know why you assume I'm not familiar with the "basic material." Nor can I see anything I've said that's contradicted by any of those - I have access to all of them. Again they're indicating that things would be bad, but they're not indicating that humanity would go extinct in a K/T sized extinction.

I didn'y say that they would go extinct, I simply challenged your claim that humans would very likely survive, and asked you to support it. Humans are a social species, very sophisticated. But you need to consider economic size. It is not just a case of one or two people surviving here and there, but enough to maintain our technology to drive our survival in a major extinction event. An organised society needs the leader, the farmer, the teacher, the doctor and so on. only then can you utilise hot shit technology to drive survival and recovery.
The problem is that you have not demonstrated how such people would survive the holocaust in sufficent numbers for it to work. It is not about raw survival rates, but rather who survives. Doctors, engineers, scientists are not born, but take years to train. You can't just get a random person who survives to dust off a book on heart surgery, read a few chapers, and they will likely perform a sucessful proceedure. Ditto with any other skill. To learn these things not only takes years, but leasure time. There is only so much you can learn "on the job". I submit to you that with so much going wrong, so much equipment destroyed, and so many people with the relevant skills lying dead, the atmosphere barely breathable [if at all], water supplies contamined, there is little confidence in assuming a good outcome. Sure, people in such a situation can and should give it a go, and hope for the best. But that has nothing to do with the probability of sucess. If there is just not enough left to work with, then it will fail.

[owheelj]

Originally Posted by Darwinsbulldog

I didn'y say that they would go extinct, I simply challenged your claim that humans would very likely survive, and asked you to support it. Humans are a social species, very sophisticated. But you need to consider economic size. It is not just a case of one or two people surviving here and there, but enough to maintain our technology to drive our survival in a major extinction event. An organised society needs the leader, the farmer, the teacher, the doctor and so on. only then can you utilise hot shit technology to drive survival and recovery.
The problem is that you have not demonstrated how such people would survive the holocaust in sufficent numbers for it to work. It is not about raw survival rates, but rather who survives. Doctors, engineers, scientists are not born, but take years to train. You can't just get a random person who survives to dust off a book on heart surgery, read a few chapers, and they will likely perform a sucessful proceedure. Ditto with any other skill. To learn these things not only takes years, but leasure time. There is only so much you can learn "on the job". I submit to you that with so much going wrong, so much equipment destroyed, and so many people with the relevant skills lying dead, the atmosphere barely breathable [if at all], water supplies contamined, there is little confidence in assuming a good outcome. Sure, people in such a situation can and should give it a go, and hope for the best. But that has nothing to do with the probability of sucess. If there is just not enough left to work with, then it will fail.

Lets imagine the meteorite hits Mexico. Southern North America, Central America and Asia are devastated, and few survive; but why would people in Europe, South America, Northern North America, Australia or New Zealand die? Only when stores of food ran out would they - which would surely be enough time for at least a few communities to get organised. Why would any equipment be destroyed in those places? Why would water be contaminated with anything other than ash (that can be easily filtered out)?

Now choose somewhere else for the meteorite to hit. Where could it hit where all of humanity would be either in the blast zone or face volcanic activity?

Put it this way - if you're talking about an extinction event where humans do go extinct, what percentage of other animals do you think would also go extinct? At the K/T extinction almost no plants from the Southern Hemisphere (ie. away from both the impact zone and the Deccan Traps) went extinct, almost all mammal groups survived, many bird groups, including large birds survived, and many large marine animals survived.

[Darwinsbulldog]

Originally Posted by owheelj

Lets imagine the meteorite hits Mexico. Southern North America, Central America and Asia are devastated, and few survive; but why would people in Europe, South America, Northern North America, Australia or New Zealand die? Only when stores of food ran out would they - which would surely be enough time for at least a few communities to get organised. Why would any equipment be destroyed in those places? Why would water be contaminated with anything other than ash (that can be easily filtered out)?

Now choose somewhere else for the meteorite to hit. Where could it hit where all of humanity would be either in the blast zone or face volcanic activity?

Put it this way - if you're talking about an extinction event where humans do go extinct, what percentage of other animals do you think would also go extinct? At the K/T extinction almost no plants from the Southern Hemisphere (ie. away from both the impact zone and the Deccan Traps) went extinct, almost all mammal groups survived, many bird groups, including large birds survived, and many large marine animals survived.

The actual meteorite that hit Earth 65 million years ago wiped out every non-avian dinosaur on the planet, if not immediately and directly, then by secondary effects of the general, massive and sustained purturbations of every physical and biological system on the planet.

Yes, groups of mammals survived, but not anything as big as a gorilla. The ancestors of gorillas and us survived. Quite a difference.

It would appear that small generalist animals did have a slight edge over others. But I don't know how useful this rule is, as groups of Foraminifera were hit real hard. This implies that the impact altered sea chemistry not to their liking. And while we are on the subject of fresh water, a significant concentration of iridium at the C-P boundary suggests to me that freshwater sources would have to be purified at a greater level of sophistication than simply straining out mud and leaves. Mass extinctions mean lots of dead and rotting animals and plants, so high levels of pathogens would also be present. That leaves wells. Many would have to be dug, because most are left open to the air, and particles, some radioactive, toxic or pathogenic, would get into open wells.

Reasons for equipment destroyed even if not in close proximity to the impact site:-

1. Ejecta falling world-wide.
2. Widespread and serious volcanic and siemic activity.
3. Powerful tsunamis.
4. High winds and storms, floods
5. Widespread fires ignited by hot ejecta
6. Riots and civil disturbances due to lack of food, general hysteria due to the psychological trauma of losing friends, jobs, home, etc, etc.
probably more but those occurred to me within one second.
Oh, and forgot contamination of many areas with radioactivity from reactors damaged by some of the above.

[owheelj]

The metabolic requirements of small mammals is greater per weight than big mammals. Thus 80kg of mouse requires more food than 80kg of human. Therefore, for small mammals to survive, there must have been enough food available. Most people attribute the survival of the vertebrates that did survive to their ability to seek shelter - something that humans not only also have, but the majority of us are in our shelters most of the time.

Your statements about water quality aren't supported by fact. Amphibians are the class of vertebrates that was least effected by the event. Even in Southern USA, studies have shown 100% survival rates of amphibian species.

Your comment about gorilla sized mammals seems to be a bit of a red-herring. Which gorilla sized mammals went extinct, and how did their global distribution, generalist diet, and intelligence compare with modern day humans?

Of course lets not forget that humans survive and sometimes thrive without any modern technology, or scientific knowledge. And it doesn't follow that all necessary equipment would be destroyed. I'm not really sure which equipment you think are crucial to the survival of the human race anyway. I'm not denying that some would be destroyed, but how much? Do you think that every city in the world would be razed to the ground? If not, then wouldn't the majority of equipment in the cities that aren't survive intact? Would every library be destroyed? If not then couldn't the people around the surviving ones regain any lost knowledge? Would every city riot and destroy everything they needed for survival?

On the question of disease - when you look at places around the world that do suffer enormous local catastrophes there has never been a case where the entire population was wiped out by disease following that catastrophe. In fact I can't even find a case where the majority of people were wiped out by disease following a catastrophe. There are many parts of life that would be difficult after a K/T scale catastrophe, and many people would die and mortality rates would be huge for generations after the event, but none of that implies that humanity would go extinct, or that we'd be likely to go extinct. In fact we are one of the best placed animals to survive, and the only other specific species that I'd predict surviving are the ones that we've spread around the globe.

[Darwinsbulldog]

owheelj wrote:

The metabolic requirements of small mammals is greater per weight than big mammals. Thus 80kg of mouse requires more food than 80kg of human. Therefore, for small mammals to survive, there must have been enough food available.

In relative terms yes, not absolute terms. Smaller mammals have higher relative energy expenditure relative to larger ones because of their high surface area to mass ratio. Say an 80 gram mouse needs to eat it's own body weight per day to maintain. That is 80 gram per mouse per day. True, humans don't use anywhere near that ratio. But there are more small bits of food than large bits, and mice can find them better and use less energy to get to them. For example An 80 gram piece of bread, scattered into many pieces in the crevaces of a couch is easy meat to collect for Mickey, but not for Bart the Human. He needs slices of bread, wheras the mouse can utilise both crumbs and slice.

Most people attribute the survival of the vertebrates that did survive to their ability to seek shelter - something that humans not only also have, but the majority of us are in our shelters most of the time.

Tell that to the Japanese tsunami victims.

Your statements about water quality aren't supported by fact. Amphibians are the class of vertebrates that was least effected by the event. Even in Southern USA, studies have shown 100% survival rates of amphibian species.

Source? But in the meantime, different taxa can handle different contaminants differently. Rats can stand 10 times the dose of radiation that will kill humans, they are also better at detecting sick rats than humans are at detecting sick people. [Without medical expertise or equipment]

Your comment about gorilla sized mammals seems to be a bit of a red-herring. Which gorilla sized mammals went extinct, and how did their global distribution, generalist diet, and intelligence compare with modern day humans?

From memory, the palaeontological literature suggests an upper limit of 60 kgs. for survival past the K-P boundary, with very few outliers. Can you give me literature that contradicts this? In fact, there were NO mammals much larger than a rat before the K-P boundary, and for millions of years after.

Of course lets not forget that humans survive and sometimes thrive without any modern technology, or scientific knowledge

Yes, they do, but of the 7 billion humans now alive, how many of those are tough hunter-gatherers and how many are urban office workers?

If not, then wouldn't the majority of equipment in the cities that aren't survive intact? Would every library be destroyed? If not then couldn't the people around the surviving ones regain any lost knowledge? Would every city riot and destroy everything they needed for survival?

I didn't say all equipment would be destroyed, but much of it would. And is it the same equipment needed for post-impact survival? Fax machines and competers are great for communications, but you can't eat them or use them directly for producing your hydroponic foods. Setting up all this kit takes TIME, and if you have not got experts on tap, then you have to take more TIME to learn.

On the question of disease - when you look at places around the world that do suffer enormous local catastrophes there has never been a case where the entire population was wiped out by disease following that catastrophe. In fact I can't even find a case where the majority of people were wiped out by disease following a catastrophe. There are many parts of life that would be difficult after a K/T scale catastrophe, and many people would die and mortality rates would be huge for generations after the event, but none of that implies that humanity would go extinct, or that we'd be likely to go extinct. In fact we are one of the best placed animals to survive, and the only other specific species that I'd predict surviving are the ones that we've spread around the globe.

More wheeling in circles.
Just because something has not happened in the past is no guarrantee it won't happen in the future. There were NO people at the K-P extinction event, so historical data does not exist to guide us of what might happen to humans.
Humans, particularly modern, urban humans are not strong for their size. Can you imagine a city where there is moderate damage to highways an railways? No problem if you have plenty of working front end loaders, cranes and fuel to remove debris. But the city cannot survive for a day without imports of food and clean water, exports of waste and garbage, and so on.

Whay if it takes a week to dig out a front-end loader, then more days as you find fuel to power it and parts to repair it, and find mechanics to service it? Whaty if you need a 100 to clear the main raods? And only then can you get trucks in, assuming you have also spent a lot of time to dig them out, repair them, and stock them with food....from where? Crops ruined by tsunamis, earthquakes and lava blocking roads to the farms or your hydroponic plants [which you have not built yet, by the way]. You don't seem to realise the sheer SCALE of likely damage.

None of this guarrantees extinction, nor does it make survival very likely. There are too many unknowns to make a firm call either way.

[owheelj]

Originally Posted by Darwinsbulldog

owheelj wrote:

In relative terms yes, not absolute terms. Smaller mammals have higher relative energy expenditure relative to larger ones because of their high surface area to mass ratio. Say an 80 gram mouse needs to eat it's own body weight per day to maintain. That is 80 gram per mouse per day. True, humans don't use anywhere near that ratio. But there are more small bits of food than large bits, and mice can find them better and use less energy to get to them. For example An 80 gram piece of bread, scattered into many pieces in the crevaces of a couch is easy meat to collect for Mickey, but not for Bart the Human. He needs slices of bread, wheras the mouse can utilise both crumbs and slice.

I'm not sure you read what I said. What requires more energy 80kg of mouse, or 80kg of human. Haven't you merely repeated what I said through your attempt at explaining the same concept? It's probably unnecessary for you to keep repeating me. The point I was making is that size doesn't explain why small and large dinosaurs went extinct, but mammals, birds, amphibians, fish, and reptiles did not. To say that only small mammals survived isn't an argument for why humans would go extinct. Why did small dinosaurs go extinct? Why did large flightless birds survive? The reason is behaviour, and humans can demonstrate the same behaviour as the surviving animals.

Tell that to the Japanese tsunami victims.

The majority of people living in the coastal towns hit by the Japanese tsunami survived. 500,000 people were made homeless and 10,000 were killed. There was no chance of this event killing even a majority of people in the area.

Source? But in the meantime, different taxa can handle different contaminants differently. Rats can stand 10 times the dose of radiation that will kill humans, they are also better at detecting sick rats than humans are at detecting sick people. [Without medical expertise or equipment]

Well my source was studying this topic in geology at university, but here's the top result of a google search.

http://en.wikipedia.org/wiki/Cretace...ent#Amphibians

As I'm sure you're aware, amphibians tend to be fairly sensitive to water quality changes.

From memory, the palaeontological literature suggests an upper limit of 60 kgs. for survival past the K-P boundary, with very few outliers. Can you give me literature that contradicts this? In fact, there were NO mammals much larger than a rat before the K-P boundary, and for millions of years after.

You seem to have misunderstood my point, which can be the only explanation for you repeating it. Because there were no gorilla sized mammals at the extinction, it's not convincing for you to tell me that none survived - hence a red-herring.

Yes, they do, but of the 7 billion humans now alive, how many of those are tough hunter-gatherers and how many are urban office workers?

We're not talking about how many people would survive, we're talking about whether humanity would go extinct or not. There's a global "survivalist" movement, there are hundreds of published books on "survivalism". We only need a single community of 5000 people to survive the catastrophe for humanity to have a greater than 90% chance of surviving into the indefinite future (note that I see we need to them to survive, so if you bring up the same retort as last time - that they might not survive, that's not addressing what I've said needs to happen). If 99.99% of humans are killed by the catastrophe, that's not enough for us to go extinct (and especially if the deaths aren't distributed evenly, which you wouldn't expect them to be).

I didn't say all equipment would be destroyed, but much of it would. And is it the same equipment needed for post-impact survival? Fax machines and competers are great for communications, but you can't eat them or use them directly for producing your hydroponic foods. Setting up all this kit takes TIME, and if you have not got experts on tap, then you have to take more TIME to learn.

I don't follow why you think fax machines or computers are necessary for preventing human extinction. Hydroponic food production is already set up. There are already massive stockpiles of food, including preserved canned food. And, of course, the amount of expertise needed to set these things up isn't even particularly high. I know a number of people with hydroponic and/or aquaponic setups, and at least one of those people has no relevant qualifications.

More wheeling in circles.
Just because something has not happened in the past is no guarrantee it won't happen in the future. There were NO people at the K-P extinction event, so historical data does not exist to guide us of what might happen to humans.
Humans, particularly modern, urban humans are not strong for their size. Can you imagine a city where there is moderate damage to highways an railways? No problem if you have plenty of working front end loaders, cranes and fuel to remove debris. But the city cannot survive for a day without imports of food and clean water, exports of waste and garbage, and so on.


Whay if it takes a week to dig out a front-end loader, then more days as you find fuel to power it and parts to repair it, and find mechanics to service it? Whaty if you need a 100 to clear the main raods? And only then can you get trucks in, assuming you have also spent a lot of time to dig them out, repair them, and stock them with food....from where? Crops ruined by tsunamis, earthquakes and lava blocking roads to the farms or your hydroponic plants [which you have not built yet, by the way]. You don't seem to realise the sheer SCALE of likely damage.

Again, you're not demonstrating any risk of extinction. Do you really think humanity would go extinct if we couldn't fix highways? You do realise that many people survive outside of cities and grow their own food. I'm not talking about humanity just brushing off the catastrophe and a few years later being in the same position as before, I'm talking about small, isolated, communities banding together to produce food and survive through the catastrophe. You don't seem to understand what extinction is. Extinction means every community on the planet would not find solutions to the changed environment.

Originally Posted by Darwinsbulldog

None of this guarrantees extinction, nor does it make survival very likely. There are too many unknowns to make a firm call either way.

Originally Posted by Darwinsbulldog

I am not saying it would be impossible for humans to survive, just very unlikly.

Which is it? Unlikely, or unknown?