Monday, August 18, 2008

Extinctions R US

Kaloula sp., a microhylid found on campus
I found a specimen of the Painted toad and photographed it. Last of the four amphibians I am certain are on campus. There should be more but I don't know for sure. (Older post for context)

And then I was treated to these two stories based on research from this supplement of PNAS. Leakey and Lewin have said before that we have been responsible for extinctions in the past. I think the setting for their scenario was in Africa. A paper from the PNAS issue has a similar theory based on new evidence implicating humans in the extinction of Tasmanian megafauna. Giant sloths, giant kangaroos, marsupial rhinos, leopards, that no longer walk this earth at least partially due to our ancestors.

And then another paper, that implicates us in an ongoing one, that of the amphibians. Where we exacerbate the effects of the fungus that is affecting them through global warming. These animals that have survived four mass extinctions, are too fragile for human messes.

One can only wonder when it's going to be our turn.

8 comments:

Anonymous said...

If you appreciate the evolution of species, then in the chain, the most evolved/adopted will be surviving. There is no reason for the evolved species to be concerned for the other species unless there is a benefit to the former.... Considering the evolution analysis what would be your stand....

~ram

Natasha said...

That is a slightly naive understanding of both evolution and adaptation. There is no such thing as most evolved. There is no ladder or chain of ascent to humans. Even the merest bacteria present today are as evolved as us! Their lineage is in fact much longer than ours, so in some terms they are in fact more evolved. Do read more on this. This is a fairly common misconception people have and its worthwhile to be rid of it.

As for adaptation, adaptation is very local, in both time and space. What is optimally adapted now and here will not be somewhere else or later on. So maybe you are adapted to your current environment but maybe in a short while/ distance you won't be. Hence the concept of having as many species as possible, so at least some survive a drastic change in the world. Now think of crops, as you can see it might be good to have as many different kinds of crops as possible so at least a few manage in new conditions in case global warming happens!

Ok, finally about direct benefits, versus indirect benefits from species, versus species as indicators. Well, off course, one reason to conserve species is when they benefit us directly. But even those that don't do have effects on our life indirectly. For instance the disappearance of bees in the US and UK which is going on currently. Bees seem like a nuisance right? We can make do without honey. Most of them don't even make honey. Yet bees pollinate all our crops, all of them. Their collapse would lead to massive food shortages because our crops wouldn't bear fruit. Bats eat mosquitoes, snakes eats rats. Its all connected somewhere.

Yet others act as indicators, frogs in particular are very sensitive to many environmental disturbances. Which will eventually affect us. And so watching them is like an early warning system and when they are doing badly, they are telling us something about the state of our planet.

Anyway, thats the very quick primer on evolution/adaptation and conservation.

I will try and come up with some kind of reading list if you like.

Rahul Siddharthan said...

My answer to anonymous would be: if the majority of humanity thinks like that (or a sufficiently influential minority does), Darwin will have the last laugh. We can't survive without other species, but many other species will survive us. We may drive ourselves to extinction, together with hundreds or thousands of other species, but life on the planet will go on. "Fitness to survive", as you point out, has nothing to do with intelligence.

Natasha said...

Well, true. The trouble is a large number of people do not at all appreciate just how the loss of some species actually is any indicator that we're all going the same way.

Somewhere along the way, us ecologist types just took on the onus of explaining this to as many people as possible. In order to at least try and influence the course of events. So, I suppose I will keep plugging at it.

I think ram is probably just being provocative. Or so I hope.

Anonymous said...

Oops.. I am sorry! May be I could not convey what I want to!@#

Anyhow, the remarks are excellent. I totally agree with both of your argument that there is an fine twine connecting everything.

I feel that the problem becomes alarming only when humans tend to be separated from nature.

When the rest of the world is grouped and seen as a different entity.

When humans start to influence and manipulate the nature.

When we egoistically claim that we have conquered nature....

It is like seeing the light with light..Killing yourself and claiming the victory..

Humans have reached the state where this world is meant only for them.. They don't bother for others.. Very complicated.. ("words are ambiguous and am not able to write what I want. my sincere apology and I don't have any ego to admit this")

But what I wanted to clearly know whether the following statements are true or not ?

1. Species evolve naturally and as the same way some become extinct..

2. When any species is found to be extinct it is very often exagerated so that the news become more sensational (I am sorry, but I am very frank)

3. If some species could become naturally then why do you want humans to be forever, let them be extinct. let the nature be natural...

Probably you can write a separate blog/post. I would like to add a final note: There is always a fight between resources and utilisation.

When the resources become scarce, then problem comes out. Resources became scarce because of over population of one species, we the humans. all the ecological problem may be solved if the population is checked...

~ram

Rahul Siddharthan said...

Ram: I agree with your point 1. Many mass extinctions occurred long before humans appeared on the scene. So did many drastic changes in global climate. As to your point 3, I think it is natural for humans to want to preserve their own species. No ecologist that I know would advocate extinction of humans to save the planet (but they would want to save the planet to prevent extinction of humans, among other things).

I don't know about point 2. Extinctions may happen in the natural course, but human-aided extinctions still seem avoidable and unnecessary. The worry is of a tipping-point -- if we end up depleting a sufficient number of species or destroying a sufficient quantity of natural habitat, it could cause drastic changes to the ecosystem. (Being from a physics background I view the thing as a dynamical system. It may be robust to small perturbations, but slightly larger perturbations could cause huge and unforeseeable changes.) So I don't think the media fuss over human-related extinctions is in any way unjustified. It is true we can't do anything about what occurred at the hands of ancient humans in Australia thousands of years ago, but it may still hold lessons for us in the future. Australia is today largely desert and brush, and at one time it seems to have been largely tropical forest. We don't want that to happen elsewhere.

About overpopulation: I am optimistic, population growth has slowed sharply over the world and population is actually falling in many developed countries.

Aprameya said...

I ended up here searching for "Red Munia" on google. My compliments to Natasha on some of the truly stunning photographs on flickr that I have seen. I think I will be coming back here often (for someone who has been thinking of buying a DSLR for a long time now, photos like these make me want to buy one right away)

Cheers

Anonymous said...

Nats, I agree with you and i think it is a wonderful and also a simple way to put the message across. Just one more thing that i would like to add ( as if the earlier arguments by u and rahul were not enough) that if really some of us do think that we are the " mighty humans" "the epitome of evolution" ( which i understand is not what ram thinks but might so imply) then we must also remember that, if indeed anthropogenic activities cause extinction of species, we humans have something as a conscious... can we justify something like pushing other species to the brink of extinction?

mj