Biodiversity: Is it Important?

[Famine]

I was watching a Schools video the other day (I was recording it onto a DVD+RW) called "The Day of the Rhododendron". It seems that this deceptively simple plant has found a niche in an alien environment (Snowdonia) and is outcompeting everything by virtue of it's near-indestructibility. The Rhododendron is seen as "the enemy" because it's "destroying biodiversity".

Is this seriously a "bad thing"?

We're told how mankind is wiping out various species - we're the dominant species, so it's out problem, apparently - usually of the big or cuddly variety (insect species die too, but they generally get forgotten next to whales and tigers) - so we're also destroying biodiversity, I guess.

Without a wide selection of species, evolution doesn't occur (well, sort of). A speices needs competitors to provide impetus to the evolutionary processes - there's nothing like the threat of being wiped out to make you change your habits. But then one species becomes dominant at the others' expense, leading to a bottleneck in biodiversity - then another alien species is introduced and it all starts all over again. Perhaps that's what the Rhododendron is doing - killing everything else around it until it too has a competitor species to fight with. Plant eugenics?

We're told that plants may provide us with the next penicillin, or a magic bullet - and if we wipe them out then we too may die out (preposterous, but often used by alarmist green activists) - why would that be bad? If we don't survive, another species will become dominant. The loss of biodiversity in the rainforests leads to our demise and a massive gap for whichever species takes it - evolution in action.


I forgot to add, originally, that more than 99% of ALL species that ever existed are extinct today - some due to being out-competed by other species but most through the major cataclysmic extinctions (the last big one was 65 million years ago, but was nothing next to the Devonian Era extinction). What difference does one more or less make?


Anyway, is biodiversity important to you?

 

[ledhed]

I like mushrooms.

 

[Danoff]

Without a wide selection of species, evolution doesn't occur (well, sort of). A speices needs competitors to provide impetus to the evolutionary processes

Human beings are not undergoing evolution anymore. We are no longer subject to natural selection, so evolution does not occur. If anything, we are de-evolving (which I recognize is evolution in some sense, but not the sense people usually think of).

 

[ledhed]

Danoff what makes you believe that humans are incapable of further evolution ? if you look back 50 years ago and compare sports figures from today you find bigger faster stronger atheletes . would you say thats due to evolution or coincedence ?

 

[Danoff]

Danoff what makes you believe that humans are incapable of further evolution ? if you look back 50 years ago and compare sports figures from today you find bigger faster stronger atheletes . would you say thats due to evolution or coincedence ?

Sports is more of a franchise today than it was. People train harder and start younger.... and of course... juicing up helps.

Evolution is ruled by natural selection. The fittest survive and pass on their genes and the unfit do not survive.

Humanity (at least in first world countries) does not face that today. Both the fit and unfit survive and pass on their genes. If almost everyone's genes get passed on, how can natural selection occur?

Humanity is not evolving to become more fit. Instead our gene pool is getting mucked up by all of the biological mutations and disease that are perpetuated from generation to generation. The result is a gradually less fit species. While there will most certainly be exceptions (michael jordans etc.) as a whole we're carying more genetic junk.

Another way in which we're de-evolving is that in general stupid people tend to procreate more often than smart people.


In summary, the only way evolution occurs is if some genes are rejected because the person does not procreate. Almost everyone procreates these days so it isn't happening.

 

[eddieturner2002]

We are no longer subject to natural selection

So are you saying that when the male releases all his 'little-uns', the one who gets to the egg first is totally random; rather that the strongest, most enduring one getting there first.

 

[Famine]

Evolution is ruled by natural selection. The fittest survive and pass on their genes and the unfit do not survive.

Humanity (at least in first world countries) does not face that today. Both the fit and unfit survive and pass on their genes. If almost everyone's genes get passed on, how can natural selection occur?

Humanity is not evolving to become more fit. Instead our gene pool is getting mucked up by all of the biological mutations and disease that are perpetuated from generation to generation. The result is a gradually less fit species. While there will most certainly be exceptions (michael jordans etc.) as a whole we're carying more genetic junk.

You are of course aware that "survival of the fittest" refers not to the most physically fit, but to those most suited to their environment?

Our environment - in first world countries at least - is that of extreme medical technology. All of those that survive to pass on their genes ARE the fittest, as they are best suited to this environment.

Many of the biological mutations (which of course is the very foundation of evolution) and disease to which you refer convey sterility. By far the most common autosomal genetic disorder is cystic fibrosis, and nearly all cystic fibrosis sufferers are sterile. Haemophilia does not cause sterility, but female haemophiliac embryos are almost always automatically aborted by the body during very early pregnancy. Polyploidy disorders - Down's Syndrome, Kleinfelter's Syndrome, Turner's Syndrome - all cause sterility (except some unusal Kleinfelter's cases). Genetic diseases rarely survive one generation to the next - however the number of carriers is staggering.

Sickle cell anaemia is a genetic disorder - however carriers of the disease show resistance to malaria. Sickle cell carriers form nearly 85% of the population in regions where mosquitoes are prevalent - in this case both "normal" and sickle cell sufferers are the least fit for their environment, because they'll either die from lack of oxygen transport or malaria, but the carriers are the most fit for their environment because, although they have a slightly compromised ability to transport oxygen, they are resistant to the major killer of the region. Genetic junk? I think not.


Also remember that evolution is not only ruled by natural selection, but also by artificial selection. Have a close look at your dog, cat, hamster or horse - all have been artificially selected for desirable characteristics and show distinct differences from ancestors only 100 years ago (or 80 in the case of hamsters).

 

[daan]

How can spoon be in the lead when there isn't one?

 

[Danoff]

Our environment - in first world countries at least - is that of extreme medical technology. All of those that survive to pass on their genes ARE the fittest, as they are best suited to this environment.

Meaning no evolution. Because nobody is weeded out.

Genetic diseases rarely survive one generation to the next - however the number of carriers is staggering.

If they're genetic and they don't get passed on, how does anyone get them?

I'm not talking about extreme cases here, I'm talking about the population at large. People have genetic eye problems, flat feet, or weak hearts. All of these are passed on genetically... all of which would be removed from the gene pool if natural selection were still at work today - and that would include me getting removed.

Sure some diseases will cause sterility and some people will not reproduce. But in large part, human (first world country) reproduction is not a function of fitness or suitability to environment.

Also remember that evolution is not only ruled by natural selection, but also by artificial selection.

so the application to humans is?


This one only pertains to people in China.
because they don't like to have baby girls


-------------------------

So are you saying that when the male releases all his 'little-uns', the one who gets to the egg first is totally random; rather that the strongest, most enduring one getting there first.

Um... NO! Not at all what I'm talking about.

 

[Danoff]

Anyway, is biodiversity important to you?

I don't think we should go out of our way to save other species. At the same time, I don't think we should be wiping them out without a care either. There is a balance in between "save the almost extinct salimander" and "kill all the whales".

 

[Arwin]

Physical evolution is slow, very slow. In 100.000 years, there is hardly a noticeable change. We're hardly even different from apes. Our true evolution lies in our social development. Like ants, we have discovered that we can be more powerful if we work together, only we took it to a whole new level. The incredible speed of this evolution made us unstable at times, but also incredibly powerful.

Since evolution takes such a long time to evolve, species are more valuable than diamonds. They tell us how the world came to be what it is today, and how we came to be what we are today. We are not like the previous dominant species, the dinosaurs. We can see the meteorite coming. I believe life is a special and valuable thing, and even if it is not unique in time or this universe, I feel it is something rare and special. I think we have a duty to protect it and let it develop, even beyond the boundaries of our earth. It's very easy to say hey, if we don't make it then the next species will do better, but considering how long it has taken even for our species to come around, a meteor might come and squash all life on this planet, maybe even take out the planet altogether.

We know that this planet will one day become uninhabitable. If our species dies, that knowledge dies, and before and if ever it revives, it may well be too late. We don't just hold our own lives in our own hands, but life itself.

The history and development of life has proven to be very valuable knowlegde. Had humans killed off all other species, we might not even have figured out the whole concept of evolution yet, and would certainly have known a lot less about it. I say a little respect for life doesn't hurt, and I wouldn't willingly throw anything away until we know the value of it. Once we do, we can determine if it's worth keeping. If we don't, we just simply don't know what we're missing. I'm not saying protect all species at all costs - yes, species get extinct all the time. That too is part of evolution. But if we have the power and means to keep a species, it's worth considering. Everyone who's watched something like Animal Planet for a few hours knows that there's so much to learn.

 

[Famine]

Meaning no evolution. Because nobody is weeded out.

Or meaning more effective evolution, because the gene pool is much, much larger?

See "sickle cell anaemia".

However, plenty of people are still "weeded out", despite medicine's best efforts - and many because of their genetic make-up.

If they're genetic and they don't get passed on, how does anyone get them?

I'm not sure you've totally understood the nature of the diseases I mentioned.

The nature of having the disease will include sterility. However since most of the diseases are recessive (you must have two copies of the "faulty" gene to suffer with the disease) the disease allele can persist in populations without causing disease in the majority of children.

And of course, as I mentioned with sickle cell anaemia, the effect of carrying the disease can confer a higher chance of survival. Stick a sickle cell carrier in a US school and he might not be able to keep up for a full basketball game. Stick Michael Jordan in a mud hut on the banks of the Ganges and he might not live the year.

Thus the "defective" allele persists throughout the ages.

I'm not talking about extreme cases here, I'm talking about the population at large. People have genetic eye problems, flat feet, or weak hearts. All of these are passed on genetically... all of which would be removed from the gene pool if natural selection were still at work today - and that would include me getting removed.

None of those problems would prevent, in the majority of cases, an animal or human reaching breeding age - which is the ONLY criterion in natural selection. Interesting note - sabre toothed tigers (sometimes referred to as "sabre-toothed cats") lived in a co-operative community, helping out those animals which were weaker than the rest.

so the application to humans is?

See "Beta Thalassaemia in Cyprus". And possibly "The Third Reich". Or "The Royal Families of Europe, 18th/19th Century". And, at a less extreme level, "ICSI" or "SUZI" (which turns cystic fibrosis's effect on sterility into a mere hurdle).

 

[Arwin]

And of course, as I mentioned with sickle cell anaemia, the effect of carrying the disease can confer a higher chance of survival. Stick a sickle cell carrier in a US school and he might not be able to keep up for a full basketball game. Stick Michael Jordan in a mud hut on the banks of the Ganges and he might not live the year.

Thus the "defective" allele persists throughout the ages.[/color][/b]

None of those problems would prevent, in the majority of cases, an animal or human reaching breeding age - which is the ONLY criterion in natural selection.

It is not. You still have to produce the offspring. And how about the fact that our eyesight is rapidly deteriorating. But I know what you are saying. Evolution is chaotic, and things that may appear weaknesses can suddenly turn out to be a great strength under changing circumstances. The power of our brain combined with our cultural memory means that we can adapt to a great many different circumstances without having to adjust our DNA. By becoming less and less dependent on our bodies, the priority of our fitness in evolution becomes lower, and we can to a certain extent afford some physical 'devolution', in the sense that we don't need perfect eyesight anymore in our self-shaped society because we can put contact lenses in, and eyes carrying those lenses will (pretty soon actually) become superior to eyes not carrying those lenses, at least in the society as it is shaped today. If a meteorite or war could hit us and block out the sun, then provided life is still possible at all, those with better night vision or hearing will have a greater chance of survival. Diversity is key. Evolution is an interesting process, that doesn't necessarily favor the fittest, but the fittest given the current circumstances. And circumstances tend to change a lot.

 

[Danoff]

I'm not sure you've totally understood the nature of the diseases I mentioned.

I do not want to limit this discussion to the diseases you mentioned.

However, plenty of people are still "weeded out", despite medicine's best efforts - and many because of their genetic make-up.

You just said medicine's efforts were to prevent natural selection - which is my point.

None of those problems would prevent, in the majority of cases, an animal or human reaching breeding age - which is the ONLY criterion in natural selection

Even though Arwin points out that this is not completely true, I know what you mean here and I agree. Reproduction is the ONLY criterion for natural selection. Which is my point.

See "Beta Thalassaemia in Cyprus". And possibly "The Third Reich". Or "The Royal Families of Europe, 18th/19th Century". And, at a less extreme level, "ICSI" or "SUZI" (which turns cystic fibrosis's effect on sterility into a mere hurdle).

I thought my comment about China would tell you that I knew there were small instances (small in the role they have played for our species so far). However, for humanity at large there is no artificial selection.


I don't know why you're dodging the conclusions here Famine. I expected you of all people to agree with me here. In places where medicine is available relatively (percentage wise) few people die before generating offspring. The result is that natural selection is playing almost no role for humanity and that human beings are no longer adapting themselves (in the big picture) to our environment.

Examples:
Evolution won't take care of cancer because most people reproduce before they get cancer. Ditto for heart disease (I think these are the number 1 and number 2 killers of Americans). For the very same reason, human beings aren't going to lose their body hair, or evolve into having 6 fingers, or a larger brain... not without some sort of reproductive engineering.

The reason for this is (and this is my point) having 6 fingers, or less body hair, or a larger brain, does not increase chances of procreation.

 

[Danoff]

The power of our brain combined with our cultural memory means that we can adapt to a great many different circumstances without having to adjust our DNA. By becoming less and less dependent on our bodies, the priority of our fitness in evolution becomes lower, and we can to a certain extent afford some physical 'devolution', in the sense that we don't need perfect eyesight anymore in our self-shaped society because we can put contact lenses in, and eyes carrying those lenses will (pretty soon actually) become superior to eyes not carrying those lenses, at least in the society as it is shaped today.

This is all claiming that our evolution up until now has been so effective that we are prepared as a species to take on just about anything. That doesn't mean that natural selection is at work. In the general application of the word evolution our species is evolving - hell - people evolve when they go to college in the general application of the word. However, in the biological definition of the word evolution, none of this technological augmentation or cultural change counts as evolution - not until you start changing our genetic code.

 

[Famine]

Examples:
Evolution won't take care of cancer because most people reproduce before they get cancer.

Actually, almost everyone who suffers from an inherited cancer will be affected before they start to exhibit - except for inherited breast cancers which tend to be "encouraged" by oestrogen released at puberty. The majority of inherited cancers are extremely aggressive and tend not to be survivable.

Most cancers are simply a result of age or tissue damage through exposure to teratogens (mainly ultra-violet).


However, this doesn't invalidate your point. It's just an FYI.

While I agree that evolution is no longer as important to humanity as a species, it does still occur. Circumstantially, you can review the evidence of average heights over the last 150 years - on average we're nearly a foot taller. This is genetic - but what increased height has to do with "fitness" to reproduce escapes me.


Anyway, back on to biodiversity...

It appears that humanity is not always wiping out species, but also causing evolution in them too. Notwithstanding the common rat, which thrives as a result of human population, an interesting example reminded itself to me earlier today.

Bird populations in the UK - specifically hedge-dwelling birds - seem to have adopted an unusual characteristic which directly confers survival. Before the advent of the car, this was rarely seen but seems to have forced it's way into hedge-birds' genetic memory. Almost all hedge-birds now, upon flying from a dense environment (trees, hedges) into a clear environment bank sharply upwards. Birds which "stoop" do not fly into passing cars. Birds which do not stoop, die. They have evolved to "stoop" as a direct result of the car - a trait which can only have arisen during the last 120 years...

 

[Firebird]

Biodiversity is important, but most people have a twisted enviromentalist interpretation of biodiversity. Most people believe biodiversity means maintaining the status quo. That simply isn't going to happen, due to both the 'natural' progress of evolution and the interference of the dominant species of the planet. The dominant species being homo sapiens, of course. New species evolve, old ones die off. Biodiversity will always be maintained no matter how badly we **** up Earth.

 

[Arwin]

[While I agree that evolution is no longer as important to humanity as a species, it does still occur. Circumstantially, you can review the evidence of average heights over the last 150 years - on average we're nearly a foot taller. This is genetic - but what increased height has to do with "fitness" to reproduce escapes me.

Very circumstantial indeed. There's however a tonne of research data showing that better food is a very big part of it. We read quite a bit about that here being the tallest people in the west and all. Interestingly enough, this increase in length through food exposed differences between the Norwegians and the Dutch. The Norwegians have a certain 'upper limit' in their genes, while the Dutch appear not to. Which is why more and more get anti-growth hormones - the body can't handle it.

The important thing to remember is that while people are growing taller, the DNA hasn't really been changing these last 100.000 years apparently. We still see a lot of change, because especially mammals seem to be rife with adaptability features.

Anyway, back on to biodiversity...

Bird populations in the UK - specifically hedge-dwelling birds - seem to have adopted an unusual characteristic which directly confers survival. Before the advent of the car, this was rarely seen but seems to have forced it's way into hedge-birds' genetic memory. Almost all hedge-birds now, upon flying from a dense environment (trees, hedges) into a clear environment bank sharply upwards. Birds which "stoop" do not fly into passing cars. Birds which do not stoop, die. They have evolved to "stoop" as a direct result of the car - a trait which can only have arisen during the last 120 years...[/color][/b]

Maybe, but it also seems to me a very natural response in reaction to most natural predators. Any other direction than up is very likely to be unsafe; for instance, cats can lie in wait for 24 hours near the exit of any animal dwelling.

Now that DNA technology has evolved so much and the human genome is getting charted completely, we'll learn a lot about evolution in the last 100.000 years. I think we'll have an interesting decade in evolutionary science ahead of us.