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Do We Need So Many Other Animals on Earth?


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The Earth is swarming with all kinds of animals. Most of these don't seem to help human survival. Why do we want them hanging around?

 

Recently I found a leaflet in my weekly Science magazine. The leaflet was about the Siberian tiger, or some kind of tiger. These tigers are apparently getting scarce. Only 700 left, or something like that.

 

The leaflet exhorted me to pay some money to "sponsor" one of these things, so they wouldn't die out. Well, frankly I don't really care whether they die out or not. They don't seem to be contributing anything to my life. Or human life in general. Who'd miss them?

 

The only animals we'd miss, are the ones we eat. Like cows, pigs and chickens. If these died out, our diet would suffer. To ensure this doesn't happen, we keep plenty of them on our farms. But most animals outside our farms, are irrelevant to our needs.

 

I wonder then, why some people have this obsession with preserving useless animals. Of course, these people call it "Protecting the Environment", or "Preserving Ecological Diversity", or some similar buzz-phrase.

 

But isn't it a bit irrational really?

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Actually, functioning natural ecosystems are imperative to human survival, as they form the basis of natural systems we rely upon for things like the water cycle, carbon cycle, nutrient cycling etc an

I'm fairly sure i have around a 1,000 species of bacteria in my gut and like number on my skin, so that provides a good starting point.   And to Dekan who, for some peculiar reason thinks humans ar

The problem is your perception of importance and success. Your perception of the importance and success of human beings is based on christian values and not evolutionary fact.     If the total numb

There are a lot of varying reasons. Many of which are not centered on humans of the only worthwhile animal on earth.

But even assuming that everything should only be geared towards human survival (something that I do not subscribe to) then the question is what do we need to conserve the ecosystem or at least maintain it at a level that may sustain human life.

Just keeping foodstock around is clearly insufficient.

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The Earth is swarming with all kinds of animals. Most of these don't seem to help human survival. Why do we want them hanging around?

 

Actually, functioning natural ecosystems are imperative to human survival, as they form the basis of natural systems we rely upon for things like the water cycle, carbon cycle, nutrient cycling etc and so on, all of which are critical to you and I having basics like air to breathe and clean water to drink.

 

So the question, as CharonY put is "what is the minimum species required to keep natural systems functioning?" Given that only ~10% of species on earth are actually known, the answer to that question is an emphatic "We don't know."

 

In addition to a lack of knowledge regarding the minimum number of species required to maintain the basic level of ecosystem functioning, redundancy in the system - i.e. organisms which both perform the same basic task in maintaining ecosystem function allows it to survive fluctuations which may cause the extinction of one but not the other.

 

So there's an exceptionally strong argument from a utilitarian point of view for maximizing biodiversity without any need to invoke the intrinsic value of ofthe forms of life on the planet. You wouldn't build a water treatment plant, power station or hospital without redundant backup systems and you wouldn't build an investment portfolio with no diversity to account for potential failures, so why would you limit the diversity of natural ecosystems that you critically depend on?

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Another point that should be made is or has to do with medicine, a great many bio-active compounds are found in nature, if we had to discover these compounds by simple trail and error it would take millions of years to just find one compound. Life on Earth is a invaluable resource of bio-active compounds, most of which we have yet to even know of much less test. You cannot know or even pretend to be able to predict where the next life saving bio chemical will come from, the cure for almost anything can be waiting in the venom of a tiny rare cuttlefish (actually this little guy is under investigation for it's possible medicinal qualities) or some other rare or odd animal, compounds found in sponges have been found with medicinal qualities, acidians, echinoderms, a great many fish can be health giving just by eating them. We cannot say how small the ecology can be and us still live but we do know that every time something becomes extinct a whole zoo of bio active chemicals goes extinct with it.

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Thanks CharonY, Arete, and Moontanman for your replies, which I've carefully read.

 

This is how I look at it:

 

Human beings are the most valuable animals on Earth. (I know CharonY doesn't subscribe to that, but surely we must be, as no other animals are capable of having discussions like this).

 

We should therefore arrange things on Earth, so that the planet can support as many human beings as possible. That means getting rid of all other animals, except ones we need. These would be, at first, a small number of species, needed for food. Later, these can be dispensed with - as soon as we learn how to make synthetic food from basic raw materials. Plants do that all the time, I'm sure we can too.

 

Moontanman's point about the medicinal potential of other species is valid at present. But future science will let us design our own medicines, without relying on serendipitous discoveries in the Amazon rainforest, or weird cuttlefish.

 

In general, we should treat our planet as a "space-station" for humans to live on. We already do that on a small scale - the currently orbiting International Space Station doesn't have all kinds of other animals running around in it. The Earth shouldn't either - it should be a fitting home for humanity.

 

We shouldn't be concerned with preserving Earth's existing primitive, cruel eco-structure - let's use our human powers to design a bright new civilised one!

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We are far from able to create a balanced ecosystem. The space station is not self-sustaining. The Biosphere 2 is an example to recreate a small ecosystem, which ultimately failed.

Also, why would you consider an organism to be worth more than others due to their ability to communicate in a specific manner?

Are you less worth if your abilities are in some way limited?

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The Earth is swarming with all kinds of animals. Most of these don't seem to help human survival. Why do we want them hanging around?

:

:

I wonder then, why some people have this obsession with preserving useless animals. Of course, these people call it "Protecting the Environment", or "Preserving Ecological Diversity", or some similar buzz-phrase.

Ecological pyramids consist of animals at various levels. The highest levels consist of the top predators (eg, tigers, eagles, tuna, etc). A sufficiently large and healthy ecosystem can sustain these top predators. The number and health of these top predators correlates with the size and "health" of the ecosystem that sustains them.

 

Modern science has allowed us to recognize this fact. People in the past only had a vague understanding of it. They considered top predators to be auspicious, that is, good fortune, even though these beasts also posed a danger to humans. For example, if you live near a forest that sustained tigers, we now know that the forest is large enough to contain sufficient numbers of the predator's prey species (eg: deer, elk, goats, wild boar, etc) which, in turn, indicate that the ecosystem also contains enough grasses, bushes, trees, roots, nuts, berries etc to sustain the prey animals.

 

To prehistoric "hunter-gatherers", the presence of top predators signified prosperity: animals to hunt and fruits and vegetables to gather. So, these top predators were considered auspicious. It's no wonder that prehistoric people revered or even worshiped some of these top predators.

 

On the other hand, an endangered top predator is an indicator that its ecosystem is in decline. Nowadays, it's generally assumed/known that humans have wrecked their ecosystem (pollution, deforestation, over hunting, over grazing, etc), so people tend to feel guilty about this. The most natural response would be to restore the damaged ecosystem to its original condition, thus allowing it once again to sustain its top predators. However, this sounds expensive. Efforts to artificially preserve the populations of top predators are more economically feasible.

 

only ~10% of species on earth are actually known

Just out of curiosity, how do we know the other 90% exist if we haven't discovered them already?

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Thanks CharonY, Arete, and Moontanman for your replies, which I've carefully read.

 

This is how I look at it:

 

Human beings are the most valuable animals on Earth. (I know CharonY doesn't subscribe to that, but surely we must be, as no other animals are capable of having discussions like this).

 

We should therefore arrange things on Earth, so that the planet can support as many human beings as possible. That means getting rid of all other animals, except ones we need. These would be, at first, a small number of species, needed for food. Later, these can be dispensed with - as soon as we learn how to make synthetic food from basic raw materials. Plants do that all the time, I'm sure we can too.

 

Moontanman's point about the medicinal potential of other species is valid at present. But future science will let us design our own medicines, without relying on serendipitous discoveries in the Amazon rainforest, or weird cuttlefish.

 

In general, we should treat our planet as a "space-station" for humans to live on. We already do that on a small scale - the currently orbiting International Space Station doesn't have all kinds of other animals running around in it. The Earth shouldn't either - it should be a fitting home for humanity.

 

We shouldn't be concerned with preserving Earth's existing primitive, cruel eco-structure - let's use our human powers to design a bright new civilised one!

 

Then are those who do not have the ability to have discussions such as these less than human? If so why should we not take anyone with sever brain damage and kill them? What makes humans so much more valuable? Because that's what we are?

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Just out of curiosity, how do we know the other 90% exist if we haven't discovered them already?

Extrapolation, hence the "~" symbol.

 

Dekan - humans evolved in an environment created by, and populated by other organisms. Our basic survival is entriely dependent on the actions of other organisms. If you wish to optimise the earth for human survival you need to, by definition optimise the function of the naturally occurring systems we rely on. Biodiversity increases the efficacy and resilience of these systems and what you suggest produces a demonstrable negative outcome for the human populous.

 

As for "doing away" with our reliance on these systems - they perform the functions they do many times more efficiently than any artificially devised mechanism, and for free.

 

It's an entirely nonsensical suggestion on all levels. Reducing biodiversity REDUCES the viability of the planet in terms of carrying capacity both temporally and spatially.

Edited by Arete
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Just out of curiosity, how do we know the other 90% exist if we haven't discovered them already?

Extrapolation, hence the "~" symbol.

 

Please explain how we can extrapolate that there's 10 times more species than we know exist. To me, that's like saying there's ten times as many elements in the universe than we know exists.

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Please explain how we can extrapolate that there's 10 times more species than we know exist. To me, that's like saying there's ten times as many elements in the universe than we know exists.

 

Firstly, Linnaean classification is an attempt to place categories on a system of diversification which is effectively continuous, so comparing species to elements is apples to oranges.

 

There's a discrepancy between taxonomic description and other methods of quantifying biological diversity such as rapid morphological typing and genetic barcoding. Therefore we can look at certain groups, see that the current taxonomy accounts for X% of the diversity accounted for by screening and extrapolate that the taxonomically described diversity represents a certain percentage of the species of the group. Extrapolating further, you can make a guesstimate at the current level of taxonomically undescribed biota of the earth.

 

It's back of the envelope but the point is that we currently have a poor understanding of the biodiversity of the planet and the ecological function of its constituent species so it's currently not possible to decide which ones we need and do not.

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Nowadays, it's generally assumed/known that humans have wrecked their ecosystem (pollution, deforestation, over hunting, over grazing, etc), so people tend to feel guilty about this.

 

I don't feel guilty about it. I like what we humans are doing: we're improving the Earth's ecosystem, by getting rid of all the unnecessary organisms.

 

It's like creating a garden. Do you want a mass of rank weeds in it - or pleasant pretty flowers, like roses. If your roses get afflicted by insect pests, like aphids and things, don't you spray insecticide to get rid of the pests? Is it wrong to do that?

 

What humans are doing (maybe unconsciously) is spraying the Earth to get rid of weeds and pests, so that it can become Garden Earth. Probably Gaia has evolved the human species, to fulfil the role of her gardener.

Edited by Dekan
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a) We rely on naturally functioning ecosystems for life supporting services. (e.g. Daily, 1997. http://books.google....=gbs_navlinks_s)

b) Whilst these natural systems function effectively, these services are provided for us effectively free.

c) It is costly to replace these services with artificial replacements which are considerably less efficient (e.g. water treatment can be effectively carried out by wetlands http://www.sciencedi...043135496001145).

d) Reducing the biodiversity of these naturally occurring systems reduces their resilience to change, their effectiveness and can ultimately cause the service to be no longer provided (e.g http://www.sciencema.../5800/787.short)

e) We have no accurate way of determining which, if any organisms are "unnecessary" (Reaka-Kudla, M. L., D. E. Wilson and E. O. Wilson (Eds.) 1997. Biodiversity II. Washington)

 

As such, there are considerably detrimental outcomes from humans as a result of reducing biodiversity. Can you explain how your proposal has positive outcomes which outweigh the negatives?

 

As for your rose garden. Say you spray the bugs but it turns out they were essential for pollination of your roses. What now? Pollinate by hand, when you could have done nothing and had a natural system do it for you?

Edited by Arete
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As for your rose garden. Say you spray the bugs but it turns out they were essential for pollination of your roses. What now? Pollinate by hand, when you could have done nothing and had a natural system do it for you?

 

If that happened, Arete, I would give it up as a bad job, and put artificial plastic flowers in the garden. The latest artificial flowers look extremely realistic. They only lack scent. However, I'm sure it won't be long before scent-impregnated plastic becomes available. Then I'll be able to enjoy a nice garden, without all the muck and bugs.

 

Thanks for the links you kindly supplied. I want to give proper consideration to these, but am getting a bit tired now, as it's quarter past ten, so I'll come back to you tomorrow, if I may. Cheers.

 

 

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In general, we should treat our planet as a "space-station" for humans to live on. We already do that on a small scale - the currently orbiting International Space Station doesn't have all kinds of other animals running around in it. The Earth shouldn't either - it should be a fitting home for humanity.

The ISS doesn't come anywhere close to being run as an isolated ecosystem. It requires constant resupply from earth to sustain a few individuals. Bad example.

 

 

Saying "should" compels me to ask: Is this a statement of science or philosophy/religion?

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If that happened, Arete, I would give it up as a bad job, and put artificial plastic flowers in the garden. The latest artificial flowers look extremely realistic. They only lack scent. However, I'm sure it won't be long before scent-impregnated plastic becomes available. Then I'll be able to enjoy a nice garden, without all the muck and bugs.

 

Taking your previous extrapolation to a "global garden", if your artificial roses do not transpire or photosynthesize, you lose essential ecological functions that support human life. We have real plants/forests/ecosystems that do this and many other essential sevices with zero resource and effort required.

 

You're saying that we should remove these systems and at extremely large expense and effort, replace them with some as yet undetermined artificial alternative, for some as yet undetermined benefit. What I'm saying is you can maximize these free services by simply leaving the system alone, thus improving human quality of life and not unnecessarily expending extremely large quantities of resources which could be used for other purposes. Based on these observations I'm asserting there is NO utilitarian gain from reducing the efficacy or removing ecosystem services and that contrary to your claim, reducing global biodiversity is detrimental to human carrying capacity and quality of life.

Edited by Arete
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a) We rely on naturally functioning ecosystems for life supporting services. (e.g. Daily, 1997. http://books.google....=gbs_navlinks_s)

b) Whilst these natural systems function effectively, these services are provided for us effectively free.

c) It is costly to replace these services with artificial replacements which are considerably less efficient (e.g. water treatment can be effectively carried out by wetlands http://www.sciencedi...043135496001145).

d) Reducing the biodiversity of these naturally occurring systems reduces their resilience to change, their effectiveness and can ultimately cause the service to be no longer provided (e.g http://www.sciencema.../5800/787.short)

e) We have no accurate way of determining which, if any organisms are "unnecessary" (Reaka-Kudla, M. L., D. E. Wilson and E. O. Wilson (Eds.) 1997. Biodiversity II. Washington)

 

As such, there are considerably detrimental outcomes from humans as a result of reducing biodiversity. Can you explain how your proposal has positive outcomes which outweigh the negatives?

 

As for your rose garden. Say you spray the bugs but it turns out they were essential for pollination of your roses. What now? Pollinate by hand, when you could have done nothing and had a natural system do it for you?

Arete, just to let you know that I tried to read the text in the links you courteously provided. However I gave up. They seem to be written not in clear English, but in some kind of opaque Scientologese. May I quote a sentence from one of the links:

 

" We analyzed local experiments, long-term regional time series, and global fisheries data to test how biodiversity loss affects marine ecosystem services across temporal and spatial scales. "

After struggling through that 5 times, I've got a dim idea of what it means. But what a linguistic atrocity it is! Redolent of "management-speak" at its worst. Surely, if an idea can't be put across in plain English, then the idea probably isn't worth anything. (QT and Relativity may be exceptions) .

 

Your posts are much more lucid. I'll stick to reading them from now on.

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Surely, if an idea can't be put across in plain English, then the idea probably isn't worth anything.

 

Just so we're clear - you're rejecting the content of a peer reviewed article in the journal Science because it's written in technical language you find difficult to read?

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Here is an interesting take on this.

 

http://www.scientifi...AT_EVO_20110627

 

Thanks Moontanman for the interesting Scientific American link. The plan to repopulate the US with elephants may get support from a certain political party.

 

Here in Britain, there are similar proposals to reintroduce wolves into Scotland. That seems to me, a retrograde step. Wolves were exterminated here, in (I think) the 17th or 18th century. For a good reason - because they're fierce wild animals, and sometimes attack people. Our ancestors knew that. As witness the fear conveyed in folk-tales like "Little Red Riding-Hood".

 

Now we're in the 21st century, we've forgotten the fear, and have a "cuddly" view of the animals.

 

But if they were put back into Scotland, sooner or later a pack of them would attack and eat someone. Then the lawyers would have a field day.

 

Just so we're clear - you're rejecting the content of a peer reviewed article in the journal Science because it's written in technical language you find difficult to read?

 

I'm not rejecting the content of the article. I'm deploring the obfuscatory way in which it's written.

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Is it just me who read this

"But if they were put back into Scotland, sooner or later a pack of them would attack and eat someone. Then the lawyers would have a field day."

and was reminded of one of the fairly early scenes from Jurassic Park?

 

 

Anyway, a reason, if not a particularly good reason, for keeping the animals is that if we get rid of them we cannot bring them back. It's seldom a good idea to make big changes that you cannot undo.

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Thanks Moontanman for the interesting Scientific American link. The plan to repopulate the US with elephants may get support from a certain political party.

 

Here in Britain, there are similar proposals to reintroduce wolves into Scotland. That seems to me, a retrograde step. Wolves were exterminated here, in (I think) the 17th or 18th century. For a good reason - because they're fierce wild animals, and sometimes attack people. Our ancestors knew that. As witness the fear conveyed in folk-tales like "Little Red Riding-Hood".

 

Now we're in the 21st century, we've forgotten the fear, and have a "cuddly" view of the animals.

 

But if they were put back into Scotland, sooner or later a pack of them would attack and eat someone. Then the lawyers would have a field day.

 

1) Demonstrable benefits to wolf reintroduction: http://rspb.royalsoc.../1612/995.short

2) Actual risk of being attacked by a wolf: http://en.wikipedia....acks_on_humans. 11 Known attacks on humans in the previous decade. One in a zoo. Your chances of being struck by lightning are considerably better than being killed by a wolf. http://www.lightning...gov/medical.htm

 

I'm not rejecting the content of the article. I'm deploring the obfuscatory way in which it's written.

 

The sentence is clear to me - they conducted meta-analysis of the effects of biodiversity loss on various spatial and time scales. I would expect it to be clear to an undergraduate biology student. Similar to all professional publications, scientific journals are written by scientists for scientists and assume a certain level of basic knowledge. They have to in order to convey adequate information in a concise manner. Similarly I would have trouble reading a legal journal. That's not a failure of the journal itself, but a failure of my own basic knowledge of the field.

Edited by Arete
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Let's reframe the question. Say that life isn't common in the universe, but that it's extremely rare. Now let's say that we find an Earth like planet orbiting within the habitablezone of a Sun like star and it's completely lifeless. That for whatever reason, life never developed on it. How many species would be required to create a bare bones ecosystem capable of supporting Human life? Could it be done with 1,000 species? 2,000? 5,000?

Edited by Vagabond1066
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How many species would be required to create a bare bones ecosystem capable of supporting Human life?

 

1) I'd deem the question unanswerable due to the lack of data regarding the species diversity in functioning ecosystems. (see http://www.cbd.int/gti for summary and links)

2) As you remove diversity from a system, you incrementally lose function (http://onlinelibrary.wiley.com/doi/10.1111/j.1523-1739.2005.00106.x/full) So the question needs to be framed by how many humans you want to support and how effectively.

3) Functional diversity creates resilience to environmental fluctuation (http://www.sciencemag.org/content/277/5330/1300.short). So you'd also need to asses how robust to change you want that ecosystem to be - or define exactly what environmental parameters you expect it to function under.

 

Finally, while the OP has stated that reducing species diversity is desirable (despite the outcomes being demonstratively negative), they haven't explained how. I'd turn the question back around and ask, given the demonstrated benefits, what reason is there for not preserving/maximizing biological diversity?

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