That kind of mass die-off could spell ecological disaster."
I think it more likely to signal said disaster, than be a cause. You can point to almost any massive loss of biodiversity and rightly say that it's a bad sign, and maybe bad in and of itself. That sort of ignores the problem, while diluting it.
The article presents this as some weird thing due to it being a species not normal for humans. My college biology professor said that where they end up in the body has to do with how you get exposed. If you are exposed through the usual route, they end up in the usual places. If you get exposed some other way, she told us it can be worse, they can end up in places like the brain.
I don't know how to google a citation backing that up (I tried). But I remember my professor specifically mentioning they can end up in the brain.
Tapeworms are a two stage parasite. The adult phase lives in the intestine of predators (like us). The larval phase stays dormant inside cysts embedded inside the meat of herbivores.
The adult tapeworm leeches nutrients from the intestine and lays tons of eggs, which go into the feces. These eggs then contaminate the environment and end up being eaten by herbivores. The eggs hatch inside their stomach and the larva embed themselves in the meat of the herbivore (and can even get in the brain). Finally, when the predator consumes uncooked meat contaminated with tapeworm larva, these larva further develop into adult tapeworms.
Each species of tapeworm is tuned to a specific species of herbivore. Cow tapeworm eggs often go right past us because they expect a tougher stomach than ours but pig tapeworm eggs can get confused because our stomach is similar to a pig's. Their larva can then embed into our meat, which is terrible for us but a dead end for the tapeworm (because we have no natural predators ourselves)
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To protect against intestinal tapeworms only eat well cooked meat. (For raw meats like sushi, deep freezing is also an option if done right)
Preventing tapeworm cysts is more about sanitation. Have clean water for drinking and irrigation and ensure that fruits and veggies are well cleaned. Good personal hygiene helps, in case you are already infected with an adult tapeworm (and therefore at risk of autoinfection).
Cisticercosis is one those poop-transmitted diseases. It can be prevented by giving everyone access to good sanitation and also ensuring that crops aren't irrigated with contaminated water.
I don't buy that parasites are needed to control the population of the species they target.
The predator/prey relationship already ensures that. E.g. if the number of zebras increases the food supply for lions also increases which leads to more lions which leads to less zebras. I see no need for a zebra or lion parasite here to maintain balance.
Back when I was at school we were taught that parasites - unlike all other organisms - have no essential ecological role and this article has not convinced me otherwise.
It's like saying human society needs people on welfare, thieves, and robbers to function.
Nah, neither we nor natural ecological systems need parasites.
I think it’s precisely this level of hubris toward biology and the natural world which has led humanity to the state we are in. You cannot possibly compare such a dynamic, complex system as the earth’s ecosystem to a simple, human scale analogy. Any loss of biodiversity is a tragedy. Once these genetics are lost, they are gone forever.
>I think it’s precisely this level of hubris toward biology and the natural world which has led humanity to the state we are in.
You mean this awesome state where most of our children don't die before reaching adulthood?
You should really read a history book about how horrible life was before the dawn of modern industrial civilization. Our ancestors declared war on nature for a good reason and made our lives unimaginably better this way.
> Any loss of biodiversity is a tragedy.
I bet Africans disagree. Mosquitoes have killed more humans than all wars combined. Bill Gates and company are currently trying to wipe them out to save the lives of countless millions in Africa. I am pretty sure they won't miss the "biodiversity" which keeps killing them and the people they love.
By the way, the US used to have regions plagued by mosquitos and malaria too. The parasites were systematically exterminated through chemical warfare (DDT). Do you think e.g. Florida would be a better place with malaria? With hundreds of thousands of people being killed by it every year? I don't. And I am not ashamed of this "level of hubris".
> Once these genetics are lost, they are gone forever.
Not all genes are worth preserving e.g. the ones for horrible heritable diseases.
Also what you wrote is not really true, all life, all the biodiversity on earth evolved from the same archaic cells. So "gone forever" is too optimistic / pessimistic.
I don't think he disagrees with the fact that parasites cause extreme suffering, nor that ending this suffering is a good thing.
Rather, I think his point is that there's a hidden cost to the loss of biodiversity that ridding the world of parasites entails. Moreover, his point is that ethical analyses (such as the one you present) tend to minimize the extreme complexity of biological systems, and that therefore the conclusions of such analyses should be viewed suspiciously.
Most biological systems are complex adaptive systems and handle changes quite well. Killing off a few species of mosquitoes or parasites that only live in humans, is unlikely to upset any ecosystem in a major way. Plowing up all of the native grass land in the American Mid-West to grow corn or cutting down the Amazon rain forest to grow soybeans; these are the large scale wholesale destruction of the environment that people should be concerned about.
I have a hunch that by shunting blood between different creatures, mosquitos and similar “parasites” may have -once- played a crucial role in the evolution of many species.
Whether that role is necessary now or not, we cannot know for certain. Of course though, we can and should limit their ability to cause “suffering.”
Imagine us killing all bees to extinction because their stings hurt, then realizing that they were necessary for many plants.
Mosquito's don't shunt blood between different creatures. Mosquito-transmitted diseases are transmitted via the mosquito's anticoagulant saliva or their poop. Mosquito-transmitted parasites must also be able to reproduce inside the mosquito and many go through one or more stages of their life cycle inside it.
This is why you can get malaria from a mosquito but not AIDS.
>I think it’s precisely this level of hubris toward biology and the natural world which has led humanity to the state we are in
Where billions are living longer, healthier, more peaceful, productive, less deceased lives than anybody though possible 100 years ago? Where we are on the tresshold of the possibility of maybe eliminating extreme poverty?
Back when I was at school we were taught that parasites - unlike all other organisms - have no essential ecological role and this article has not convinced me otherwise.
The article has a bunch of scientists talking about recent science that questions this assumption.
I get that we are mostly working with 0 and 1s, but god isn't this a binary vision of the world.
> no essential ecological role
"ecological role" is a purely human concept. Nature doesn't give a shit about lions, zebras, parasites, or humans ; hence it's up to use to decide what we care about. Why should a lion be more important than a tapeworm ? Because it's less ugly ?
"Ecological usefulness" appears to be shorthand for a measure on a species' critical interconnectedness. That is to say, the magnitude of the impact on other species a particular species' removal would have. If you knock out algae, you wipe out many ocean species. If you knock out certain mosquitoes, you may only jinx malaria.
Wrong. Again and again repeating the same wrong idea.
Mosquito larvae are aquatic, and the prey of freshwater fishes, toads, frogs, bats... they are directly or indirectly linked with almost everything around marshes and lakes: bacteria, algae, birds. We can expect a tsunami of unpredictable consequences for freshwater ecosystems and also for men. What if we wipe mosquito only to discover that they are necessary to controlling amoeba proliferation in water, for example?. We don't know.
> It's like saying human society needs people on welfare, thieves, and robbers to function
Malicious agents may actually play a critical game-theoretical role in promoting in-group coöperation [1]. Sort of like how teams can be made stronger with an enemy "them" to be defeated by a now-defined "us".
(That said, I agree that any parasite that preys on humans should be eradicated.)
In many ecological systems parasites really are the "top predator" that keeps a population in check. If you take away the parasites there are no other predator to take that ecological role and keep things in check.
Another important aspect of parasites is that they usually only parasitise a specific species. One place where this makes a big difference is agricultural pest control. Attempts to suppress agricultural pests by introducing predators often backfire because the predator might also eat native species or itself become a pest (like the Cane Toad in Australia). Biocontrol with parasitic wasps, on the other hand, is much more targeted: http://news.nationalgeographic.com/news/2010/07/100719-paras...
Parasites change the time constant of the exponential system, sometimes allowing other controllers to function without underdamping and violent oscillation.
It would come to that, if such an ecological catastrophe wasn't affecting lots of other fuzzier animals for promotion. Some fringers will probably do it "to raise awareness".
I'm not sure they're parasites but let's get rid of mosquitoes altogether.
As far as I am concerned, they make huge territories in the north virtually unlivable (you could still live there but you no longer want to). That's even before malaria comes into account.
This leads to a proposition to a Realm of Fungi. So you wanted to eat our crops, but I have an interesting replacement for ya...
You get used to them, or wear protection. Black flies are my least favorite. I think we may be too far north for malaria to be a real concern. I live just above the 45th, but I go north to play.
No you don't! You get used to limiting your exposure to the nature, which is hardly desirable. Considering that people actually get to enjoy nature in less wet / more sunny regions.
36 comments
[ 2.8 ms ] story [ 97.4 ms ] threadI think it more likely to signal said disaster, than be a cause. You can point to almost any massive loss of biodiversity and rightly say that it's a bad sign, and maybe bad in and of itself. That sort of ignores the problem, while diluting it.
A few more of those things vanishing is fine by me. Maybe they could DNA sequence them first.
The article presents this as some weird thing due to it being a species not normal for humans. My college biology professor said that where they end up in the body has to do with how you get exposed. If you are exposed through the usual route, they end up in the usual places. If you get exposed some other way, she told us it can be worse, they can end up in places like the brain.
I don't know how to google a citation backing that up (I tried). But I remember my professor specifically mentioning they can end up in the brain.
The adult tapeworm leeches nutrients from the intestine and lays tons of eggs, which go into the feces. These eggs then contaminate the environment and end up being eaten by herbivores. The eggs hatch inside their stomach and the larva embed themselves in the meat of the herbivore (and can even get in the brain). Finally, when the predator consumes uncooked meat contaminated with tapeworm larva, these larva further develop into adult tapeworms.
Each species of tapeworm is tuned to a specific species of herbivore. Cow tapeworm eggs often go right past us because they expect a tougher stomach than ours but pig tapeworm eggs can get confused because our stomach is similar to a pig's. Their larva can then embed into our meat, which is terrible for us but a dead end for the tapeworm (because we have no natural predators ourselves)
-----
To protect against intestinal tapeworms only eat well cooked meat. (For raw meats like sushi, deep freezing is also an option if done right)
Preventing tapeworm cysts is more about sanitation. Have clean water for drinking and irrigation and ensure that fruits and veggies are well cleaned. Good personal hygiene helps, in case you are already infected with an adult tapeworm (and therefore at risk of autoinfection).
The predator/prey relationship already ensures that. E.g. if the number of zebras increases the food supply for lions also increases which leads to more lions which leads to less zebras. I see no need for a zebra or lion parasite here to maintain balance.
Back when I was at school we were taught that parasites - unlike all other organisms - have no essential ecological role and this article has not convinced me otherwise.
It's like saying human society needs people on welfare, thieves, and robbers to function.
Nah, neither we nor natural ecological systems need parasites.
You mean this awesome state where most of our children don't die before reaching adulthood?
You should really read a history book about how horrible life was before the dawn of modern industrial civilization. Our ancestors declared war on nature for a good reason and made our lives unimaginably better this way.
> Any loss of biodiversity is a tragedy.
I bet Africans disagree. Mosquitoes have killed more humans than all wars combined. Bill Gates and company are currently trying to wipe them out to save the lives of countless millions in Africa. I am pretty sure they won't miss the "biodiversity" which keeps killing them and the people they love.
By the way, the US used to have regions plagued by mosquitos and malaria too. The parasites were systematically exterminated through chemical warfare (DDT). Do you think e.g. Florida would be a better place with malaria? With hundreds of thousands of people being killed by it every year? I don't. And I am not ashamed of this "level of hubris".
> Once these genetics are lost, they are gone forever.
Not all genes are worth preserving e.g. the ones for horrible heritable diseases.
Also what you wrote is not really true, all life, all the biodiversity on earth evolved from the same archaic cells. So "gone forever" is too optimistic / pessimistic.
Rather, I think his point is that there's a hidden cost to the loss of biodiversity that ridding the world of parasites entails. Moreover, his point is that ethical analyses (such as the one you present) tend to minimize the extreme complexity of biological systems, and that therefore the conclusions of such analyses should be viewed suspiciously.
Whether that role is necessary now or not, we cannot know for certain. Of course though, we can and should limit their ability to cause “suffering.”
Imagine us killing all bees to extinction because their stings hurt, then realizing that they were necessary for many plants.
This is why you can get malaria from a mosquito but not AIDS.
Where billions are living longer, healthier, more peaceful, productive, less deceased lives than anybody though possible 100 years ago? Where we are on the tresshold of the possibility of maybe eliminating extreme poverty?
Yeah, lets try to save a few strains of DNA.
The article has a bunch of scientists talking about recent science that questions this assumption.
> no essential ecological role
"ecological role" is a purely human concept. Nature doesn't give a shit about lions, zebras, parasites, or humans ; hence it's up to use to decide what we care about. Why should a lion be more important than a tapeworm ? Because it's less ugly ?
Mosquito larvae are aquatic, and the prey of freshwater fishes, toads, frogs, bats... they are directly or indirectly linked with almost everything around marshes and lakes: bacteria, algae, birds. We can expect a tsunami of unpredictable consequences for freshwater ecosystems and also for men. What if we wipe mosquito only to discover that they are necessary to controlling amoeba proliferation in water, for example?. We don't know.
Malicious agents may actually play a critical game-theoretical role in promoting in-group coöperation [1]. Sort of like how teams can be made stronger with an enemy "them" to be defeated by a now-defined "us".
(That said, I agree that any parasite that preys on humans should be eradicated.)
[1] http://deim.urv.cat/~alexandre.arenas/publicacions/pdf/joker...
Another important aspect of parasites is that they usually only parasitise a specific species. One place where this makes a big difference is agricultural pest control. Attempts to suppress agricultural pests by introducing predators often backfire because the predator might also eat native species or itself become a pest (like the Cane Toad in Australia). Biocontrol with parasitic wasps, on the other hand, is much more targeted: http://news.nationalgeographic.com/news/2010/07/100719-paras...
As far as I am concerned, they make huge territories in the north virtually unlivable (you could still live there but you no longer want to). That's even before malaria comes into account.
This leads to a proposition to a Realm of Fungi. So you wanted to eat our crops, but I have an interesting replacement for ya...
No you don't! You get used to limiting your exposure to the nature, which is hardly desirable. Considering that people actually get to enjoy nature in less wet / more sunny regions.
Ditch black flies too, surely.