# Evolving To Hunt In Packs?



## enlightenment (Dec 14, 2006)

As a rule, spiders are solitary creatures, and lone hunters. There are some examples of spiders which live in a colony, but these tend to be rare.

The spider is a very efficient hunter, of course, whether it relies on it's web, or an ambush attack.

I was watching an episode of 'Life' in which it showed how some animals had gravitated toward hunting in packs, rather than alone, since by doing so they could take down _larger _pray.

There are pack hunters in the invert world, as well.

Assassin bugs will hunt as a group, taking on prey larger than each individual, for they have 'learned' that in doing so, it is more beneficial than the lone hunt, and there is the added bonus of there being less chance of being _preyed upon_!

I wonder, if evolution _is_ a very slow yet ongoing process, if we one day might see spiders, T's and others, which evolve to hunt in that same manner?

A single T might not be able to take down (for example), a rabbit, yet a group could.

You get the idea.

Is this plausible, from an evolutionary perspective?


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## khaostim666 (Apr 29, 2009)

:O mabey lol

The thought of 30 turantulas jumping on a rabit made me laugh


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## enlightenment (Dec 14, 2006)

khaostim666 said:


> :O mabey lol
> 
> The thought of 30 turantulas jumping on a rabit made me laugh


Or 100 devouring a man.

For example.


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## joeyboy (Jul 19, 2008)

enlightenment said:


> Or 100 devouring a man.
> 
> For example.


meh you already get little kids(usually babies or ones that can just about crawl) being attacked by roaming armies of fire ants in America, sometimes it's fatal.

Also while reading up on fire ants I actually found this, I didn't realise changes could happen so damn quickly, 70 years is nothing! If you can get longer legs in 70 yrs, no wonder you can get completely new forms of life in millions of years.

"In just 70 years, according to a new study, lizards in parts of United States have developed longer legs and new behaviors to escape the ants, which can kill the lizard in under a minute."


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## [email protected] (Jan 9, 2009)

enlightenment said:


> As a rule, spiders are solitary creatures, and lone hunters. There are some examples of spiders which live in a colony, but these tend to be rare.
> 
> The spider is a very efficient hunter, of course, whether it relies on it's web, or an ambush attack.
> 
> ...


 
:no1::no1::no1::2thumb::2thumb::2thumb:


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## Mutley.100 (Nov 3, 2008)

I think it's possible but not really likely until such a time that it has a clear advantage over solo hunting . Predators and prey are both in an arms race to see who's better . Until such time that prey needs more than an individual to take it down I can't see tarantula's evolving into pack hunters apart from the odd species or 2 . At the moment , if food becomes scarce a single healthy individual could cope better than a group of hungry predators that would just as happily chew on each other as on a passing morsel .

This leads me to an interesting point , if lions saliva evolved into a venom or toxin would the pride mentality break down due to the ability to take down large prey single-clawedly (handedly) ?


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## Harbinger (Dec 20, 2008)

Cat sized jumping spiders hunting in packs, both cute and cuddly and deadly :gasp:


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## enlightenment (Dec 14, 2006)

[email protected] said:


> :no1::no1::no1::2thumb::2thumb::2thumb:


Did you_ like_ this idea then, Matt?

: victory:


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## Danhalen (Jun 6, 2008)

The thing is, I think it could be argued that tarantulas are pretty much an evolutionary dead end - They really are the cavemen of the spider world. 

Plus there's not really any biological need for it - they thrive on invert prey, and not so much on vertebrate. Tarantulas will experience health issues if fed regularly on most vertebrate prey.

It's much more plausable in true spiders.


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## _TiMiSdRuNk_ (Aug 27, 2008)

I wish that would happen now, i'd certainly save some tank space :2thumb:


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## GRB (Jan 24, 2008)

There is a decent book that goes into this sort of thing, by Chloe and Crespi (1997). The Evolution of Social Behavior in Insects and Arachnids

I can't remember all the details, but there are examples of sub-sociality in spiders already. They don't so much hunt in packs as web share and tackle prey together - some share prey and others don't. There's a few model genera that all seem to show social interactions of some sort, and most of them are from within the Theridiidae. 

I don't think there is any strong need (at present) for spiders to evolve social hunting however. There is a good paper by Igni Agndersson (http://theridiidae.com/pdf/Agnarssonetal2006.pdf)which highlights how sociality in spiders is likely to have arisen multiple times, and subsequently died out. Another interesting one is on Delena crassipes:

http://eligreenbaum.iss.utep.edu/Spider%20Cannibalism.pdf

http://eebweb.arizona.edu/faculty/aviles/lab/reprints/Rowell-Aviles_InsSoc_1995.pdf

The thing with sociality however is that it is costly. It's costly in terms of time and evolutionary "energy" to evolve kin recognition, to evolve sharing or communal hunting behaviours and to evolve group based defence. In fact, social spiders seem to face more parasitism than non social spiders and that may represent a possible reason why social behaviour "never caught on". Other problems come from aggregation - lots of spiders together means lots of prey for a mongoose or such. 

These costs would have to outweigh the costs of being solitary, which only seems to occur in extreme environments, either from extreme climatic conditions, or extreme competition pressures. 

Survival benefits select for group living in a soc... [J Evol Biol. 2007] - PubMed result


Even hunstman sociality hasn't caught on much, and there are only a few species with sub social interactions. I have to admit I haven't read much on social huntsman (except _Delena_) so there might be additional reasons why these are uncommon.


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## enlightenment (Dec 14, 2006)

Danhalen said:


> The thing is, I think it could be argued that tarantulas are pretty much an evolutionary dead end - They really are the cavemen of the spider world.
> 
> Plus there's not really any biological need for it - they thrive on invert prey, and not so much on vertebrate. *Tarantulas will experience health issues if fed regularly on most vertebrate prey*.
> 
> It's much more plausable in true spiders.


Unless, of course, their 'system' also evolved so that weren't so.

Just a thought.


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## Muze (Jun 20, 2007)

Vilosella are communal and do hunt together in a way.

Our slings will ambush and take down larger prey in a group and then feed together.


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## Poxicator (Nov 14, 2007)

ooh, the infamous Pamphobetues "chicken spider" comes to mind.
but I agree with Dan, dead end and no need.
However, the Indian Social spiders (Stegodyphus sp.) do attack as a group. I had a group of these which grow no larger than a small finger nail in a community candy floss web. Chuck a locust in there and they descend, small and large, grabbing a leg or other body part and pulling it to its extreme position, until the locust becomes immobile. What's also interesting about this genus is not only will members of different sacs and ages live communally but also different species. Its been noted that within 5 minutes of a new member being introduced to a community they participate in construction & cleaning of the web and attacking any potential prey.


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## enlightenment (Dec 14, 2006)

Poxicator said:


> ooh, the infamous Pamphobetues "chicken spider" comes to mind.
> but I agree with Dan, dead end and no need.
> However,* the Indian Social spiders (Stegodyphus sp.) do attack as a group*. I had a group of these which grow no larger than a small finger nail in a community candy floss web. Chuck a locust in there and they descend, small and large, grabbing a leg or other body part and pulling it to its extreme position, until the locust becomes immobile. What's also interesting about this genus is not only will members of different sacs and ages live communally but also different species. Its been noted that within 5 minutes of a new member being introduced to a community they participate in construction & cleaning of the web and attacking any potential prey.


I have read a little about these.

In the end though, if it is a 'dead end' for T's to evolve into pack hunters, why would_ this_ species benefit from doing so?

Surely if it benefits them, it would benefit T's?

Not just in hunting.

_In defence_.

T's are eaten by centipedes.

Yet, I wonder if a pede would be as keen to tackle a whole colony of T's?

I don't think they would.

Not unless the pedes themselves evolved into pack hunters!

:no1:


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## GRB (Jan 24, 2008)

Whilst centipedes do eat tarantulas, I was under the impression that the most significant source of mortality was parasitoid wasps and fungal infection. 

Regardless, "social tarantulas" would still face the same problems of any social arthropod - increased disease and parasitism, as well as the notion that big clumps of spider represent an attractive food source to tarantula predators. 

From what I understand of the "chicken spider", it is just a simple motherffspring sub social relation. It would be interesting to see if the spiderlings from previous years stay when the mother or siblings become mated and gravid. 

I think the way to think about it is that tarantulas and spiders are hugely successful as non social animals. Those that do live in social groups, colonial webs or shared burrows are those that seem to live in extreme environments. I am sure that when more is known about the chicken spider, there will emerge some highly selective pressure that can explain the abnormal behaviour. The other aspect is, that unless a similar selective pressure were to act upon other species, then it would not necessarily be beneficial to another species.


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## greenlikegecko (May 18, 2007)

we need to invent bigger bug spray quick!!..im not getting killed by 100 spiders :devil:


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## Danhalen (Jun 6, 2008)

enlightenment said:


> I have read a little about these.
> 
> In the end though, if it is a 'dead end' for T's to evolve into pack hunters, why would_ this_ species benefit from doing so?
> 
> ...


It's quite widely regarded that tarantulas essentially stopped evolving a long time ago - Nature made them the best they needed to be, and instead started working on evolving true spiders.

There is no need in nature for tarantulas to evolve into pack hunters, as there is no form of prey that that would benefit a tarantulas health that would need to be subdued in such a manner.


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## Tedlin (Feb 25, 2009)

Danhalen said:


> It's quite widely regarded that tarantulas essentially stopped evolving a long time ago - Nature made them the best they needed to be, and instead started working on evolving true spiders.
> 
> There is no need in nature for tarantulas to evolve into pack hunters, as there is no form of prey that that would benefit a tarantulas health that would need to be subdued in such a manner.


 
Nothing stops evolving unless the environment stops changing. It would be plausible for creatures to start working together in packs if the smaller, more easily caught food they used to hunt becomes extinct for instance.


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## Danhalen (Jun 6, 2008)

Tedlin said:


> Nothing stops evolving unless the environment stops changing. It would be plausible for creatures to start working together in packs if the smaller, more easily caught food they used to hunt becomes extinct for instance.


But tarantulas are opportunistic, and non selective predators - They don't have a staple diet per-se. For your reasoning to become valid, an entire size range of varying species would need to become extinct.

It really makes no sense for tarantulas to become pack hunters. Their biological traits have hardly changed in thousands upon thousands of years - opposed to that of true spiders.

That's not to say that tarantulas will not start evolving again, but along with sharks, hardly anything has changed for a very, very long time. Simply because there really is no need to. True spiders are more intelligent, agile, and more effective hunters - Why would nature evolve tarantulas when it's already onto a good thing with the trues?


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## Poxicator (Nov 14, 2007)

Tedlin said:


> Nothing stops evolving unless the environment stops changing. It would be plausible for creatures to start working together in packs if the smaller, more easily caught food they used to hunt becomes extinct for instance.


If the insects they hunt (they don't actively hunt but...) died off so would the tarantula. Quite simply they're not built to hunt, or run for any distance, or take on large prey, or even subdue small prey with venom. They are considered primitive, they develop a burrow sit inside it for the majority of time and use up as little energy as possible in capturing prey. Its naive to believe every animal is capable of adapting and evolving, nature improves on the mistakes of its predecessors and leaves behind those that have come to an evolutionary stop.


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## TEENY (Jan 4, 2008)

I think tarantulas are pretty much stuck where they are. They have no NEED to find larger prey as they survive better in insects, so have no need to evolve.


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## enlightenment (Dec 14, 2006)

Danhalen said:


> It's quite widely regarded that tarantulas essentially stopped evolving a long time ago.


Have we?


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## Danhalen (Jun 6, 2008)

enlightenment said:


> Have we?


Pretty much, yup. That's not to say that it would not continue after catastrophic climate change, but they really are the cavemen if the spider world. There have been no significant biological developments in a very long time.

Compare that to the Portia genus. Look up Portia labiata if you have the chance.


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## enlightenment (Dec 14, 2006)

Danhalen said:


> Pretty much, yup.


So humans have stopped evolving?

Surely not.

Imo, unless we self destroy, we will look, act, and behave differently, in another millenia or ten.

: victory:


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## TEENY (Jan 4, 2008)

Danhalen said:


> Pretty much, yup. That's not to say that it would not continue after catastrophic climate change, but they really are the cavemen if the spider world. There have been no significant biological developments in a very long time.
> 
> Compare that to the Portia genus. Look up Portia labiata if you have the chance.


Wow he is cool and he is VERY cute:flrt:


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## Danhalen (Jun 6, 2008)

enlightenment said:


> So humans have stopped evolving?
> 
> Surely not.
> 
> ...


Sorry, I misunderstood your question. I thought you meant "have we" in regards to the tarantula communities general views on tarantula evolution. Not have we as in "have humans stopped evolving".


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## Danhalen (Jun 6, 2008)

TEENY said:


> Wow he is cool and he is VERY cute:flrt:
> 
> image


And smarter than most rodents - This is the real path of spider evolution.


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## enlightenment (Dec 14, 2006)

Danhalen said:


> Sorry, I misunderstood your question. I thought you meant "have we" in regards to the tarantula communities general views on tarantula evolution. Not have we as in "have humans stopped evolving".


No worries.

What do you think, then?

Have humans stopped evolving?


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## TEENY (Jan 4, 2008)

Danhalen said:


> And smarter than most rodents - This is the real path of spider evolution.


Good job they are not big enough for us to be prey :gasp:


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## joeyboy (Jul 19, 2008)

enlightenment said:


> So humans have stopped evolving?
> 
> Surely not.
> 
> ...


is behaviour the same as evolution though? If genetically we're the same but our political structure and viewpoints have changed, I don't think that's evolution is it? 

Also yes I'd say we've stopped now. Reason being we negative genes are passed on too AND we hate change. 

A boy in India was born with a tail. Now they chopped it off so he might still have kids, but if he'd kept it he'd be labelled a freak. In the same light if I had been born with armoured skin people would probably say im a freak, no girl would want me, so my new armoured skin gene, even if it's advantageous, isn't going to get past on. In the same way someone with a gene causing them to get an internal problem will pass it on, because we can treat problems, though the route genetic flaw isn't treated. Animals don't have the same social laws we do and many animals rape their partner, so the strongest one passes on genes, even if psychically he looks different(two extra limbs say). That doesn't happen with humans.


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## enlightenment (Dec 14, 2006)

joeyboy said:


> is behaviour the same as evolution though?.


In some ways, I would argue 'yes', it is.


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## Danhalen (Jun 6, 2008)

enlightenment said:


> No worries.
> 
> What do you think, then?
> 
> Have humans stopped evolving?


I'm not sure to be honest. I think there are arguments for both side of the fence. In my opinion, I think that western society, technology, and lifestyles may hinder the need for us to naturally evolve.


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## enlightenment (Dec 14, 2006)

Danhalen said:


> I'm not sure to be honest. I think there are arguments for both side of the fence. In my opinion, I think that western society, technology, and lifestyles may hinder the need for us to naturally evolve.


Or, it could hasten them?


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## Danhalen (Jun 6, 2008)

enlightenment said:


> Or, it could hasten them?


In what way? :hmm: 

As a species we are becoming more and more reliant on technology, and less reliant on our bodies to survive. Evolution is at least in part driven by a need to adapt to a change in environment. 

If anything, even perks such as commercial farming, mechanised transport, and central heating are surely going against this need.


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## enlightenment (Dec 14, 2006)

Danhalen said:


> In what way? :hmm:


Well, we are already light years ahead from **** sapiens that live in other parts of the world, in terms of our science and tech. A modern western scientist, for example, is for all intents and purposes a different 'species' of human being that a tribal man, living in the rain forest.

And if we, as a species, are natural, then so too is our scientific and tech progression. We may see, for example, science use it's brilliance to 'improve' our species, make it stronger, healthier, faster, more intelligent, etc, etc, and this would cause even more of a drift from others.


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## Danhalen (Jun 6, 2008)

enlightenment said:


> Well, we are already light years ahead from **** sapiens that live in other parts of the world, in terms of our science and tech. A modern western scientist, for example, is for all intents and purposes a different 'species' of human being that a tribal man, living in the rain forest.
> 
> And if we, as a species, are natural, then so too is our scientific and tech progression. We may see, for example, science use it's brilliance to 'improve' our species, make it *stronger, healthier, faster, more intelligent*, etc, etc, and this would cause even more of a drift from others.


I see where you're coming from, and I'm not entirely disagreeing with it. But if anything we as an entire species are not as strong, healthy, or fast as generations past. In regards to intelligence, our brains are being taxed in different ways to previous generations, but different is not always better. I don't think we are generally smarter as a species, rather we have a better understanding due all the hard work our ancesters have put in, and we build on that.

Your average guest on Tricia or Jeremy Kyle will have a better understanding of technology and the western world than a tribesman living in the rainforest, but that's not to say they are smarter.


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## GRB (Jan 24, 2008)

Hmmn, there's a lot of mixed wires here.

Firstly, evolution does not forward plan; natural selection does not select features that _might _be of use in some point in the future. Conversely, features that are of no current use are not favoured in future generations (although it is often difficult to completely remove all evidence of lost structure, for example the pelvis in whales etc). 

Secondly, evolution seems to have been anthropomorphised in some of these posts, as if it places emphasis on the evolution of certain groups as it deems fit, also untrue. Both the Araneomorph and Mygalomorph spiders appeared at similar times, and represent different solutions to a similar set of niche problems. Both undoubtedly underwent considerable speciation and we have the results of such today. 

Finally, as far as I'm aware, evolution does not stop. It only _slows _in stable environments (_see _The Red Queen Hypothesis). 

I'm also interested in the evidence for a lack of significant developments - I would have thought that the different behaviours between the differently aged families within the Mygalomorphae would be evidence of evolution, as well as the differing dates of divergence between the various families.

[edit] Of course, there has been an entire page of discussion since I was drafting this...bah.


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## Danhalen (Jun 6, 2008)

GRB said:


> Hmmn, there's a lot of mixed wires here.
> 
> Firstly, evolution does not forward plan; natural selection does not select features that _might _be of use in some point in the future. Conversely, features that are of no current use are not favoured in future generations (although it is often difficult to completely remove all evidence of lost structure, for example the pelvis in whales etc).
> 
> ...



I may have been quite glib in some interpretations and such, but I feel the points made in regards to the original question are quite valid.

I'm quite interested in the first statement you made. In sightless fish, for example, would you see the removal of sight as an example of (controversial subject) de-evolution, or would you see it as a process of evolution - in regards to the sightless fish expending less energy by not utilising a useless attribute in an environment wherein sighted fish may also reside?


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## GRB (Jan 24, 2008)

Danhalen said:


> I may have been quite glib in some interpretations and such, but I feel the points made in regards to the original question are quite valid.
> 
> I'm quite interested in the first statement you made. In sightless fish, for example, would you see the removal of sight as an example of (controversial subject) de-evolution, or would you see it as a process of evolution - in regards to the sightless fish expending less energy by utilising a useless attribute in an environment wherein sighted fish may also reside?


Loss of an eye in circumstances where an eye is no longer necessary is not "de-evolution" in my opinion. Actually, I don't think De-evolution occurs - evolution is a linear progression, but it is not "progressive" in that everything has to be more complex. 

Secondary loss of structures is actually quite common, although for a vertebrate to lose an eye completely takes quite a long time (it loses function quickly, but to completely remove trace of it's prior existence can be tricky, almost impossible within genes).

An improvement can be a simplification, and if it saves energy and heightens the individuals chance of reproduction, then it is an advancement and be favoured by NS (of course, drift often intervenes!).

I suppose a better way of stating my initial comment would have been "features that are of no current use _and require energy to produce, maintain or carry,etc _are not favoured in future generations".


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## Danhalen (Jun 6, 2008)

GRB said:


> Loss of an eye in circumstances where an eye is no longer necessary is not "de-evolution" in my opinion. Actually, I don't think De-evolution occurs - evolution is a linear progression, but it is not "progressive" in that everything has to be more complex.
> 
> Secondary loss of structures is actually quite common, although for a vertebrate to lose an eye completely takes quite a long time (it loses function quickly, but to completely remove trace of it's prior existence can be tricky, almost impossible within genes).
> 
> ...


That's a very interesting take on the subject. Thank you.


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## GRB (Jan 24, 2008)

No worries. I had to study evolution quite a lot, and it's still something that interests me greatly (although I find molecular evolution painfully boring!). 

What complicates matters is our own ability to forward plan. We see loss of an eye as inherently risky, as it would be possible that such fish might eventually live in lit areas again where eyes might be massively beneficial. 

Without an ability to forward plan however, the loss of such structures makes evolutionary sense, especially if gains in inclusive fitness are garnered.


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## enlightenment (Dec 14, 2006)

Danhalen said:


> I see where you're coming from, and I'm not entirely disagreeing with it. But if anything we as an entire species are not as strong, healthy, or fast as generations past. In regards to intelligence, our brains are being taxed in different ways to previous generations, but different is not always better. I don't think we are generally smarter as a species, rather we have a better understanding due all the hard work our ancesters have put in, and we build on that.
> 
> Your average guest on Tricia or Jeremy Kyle will have a better understanding of technology and the western world than a tribesman living in the rainforest, but that's not to say they are smarter.


 
I disagree.

Despite the hysteria and the media, people are living longer, and that is expected to go on.

One day, the average lifespan of a human could be 100, rather than the 75 it is at present.

We are stronger. The record for the most weight ever lifted would be more now than it was recorded decades ago. The fastest athlete(now) would be quicker than the fastest athlete then.

As for measuring intelligence, I am not suggesting the tribesman are dumb, just different, so far removed from us in understanding and culture, that they are almost as another species. That said, our science is likely to preserve our people, while (maybe), they will eventually die out, as a tribe?


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## enlightenment (Dec 14, 2006)

GRB said:


> I suppose a better way of stating my initial comment would have been "features that are of no current use _and require energy to produce, maintain or carry,etc _are not favoured in future generations".


How about the eyes of T's?

Most are apparently near blind.

They rely on their 'hair'.

Could you see T's evolving, minus the eyes?


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## Danhalen (Jun 6, 2008)

enlightenment said:


> How about the eyes of T's?
> 
> Most are apparently near blind.
> 
> ...


There already is a blind tarantula: Hamirrhagus redelli.



enlightenment said:


> I disagree.
> 
> Despite the hysteria and the media, people are living longer, and that is expected to go on.
> 
> ...


People are living longer because of medical advancements, not a change in biology.

People can be physically stronger because of suppliments such as whey protein, and anabolics, and a better understanding of how the human body actually works (I lift weights 5-6 days a week, so I know this to be true). If anything, I believe that most people are generally physically weaker than what they would have been in years past.

In regards to tribes dying out, they have managed to get this far, and they tend to be much physically healthier than more technologically developed societies. The continued survival of their tribe may be governed by survival of the fittest. Our societies are not.


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## Craig Mackay (Feb 2, 2009)

enlightenment said:


> I disagree.
> We are stronger. The record for the most weight ever lifted would be more now than it was recorded decades ago. The fastest athlete(now) would be quicker than the fastest athlete then.


Things is though, that these people such as Usain Bolt have spent a huge portion of their life training for such activities. The average Joe is not as fit and strong as they used to be and as Dan says the increase in average lifespan is mostly down to medical advances. We have learned how to get the most from our bodies through excercise, medicines and a better understanding of human biology and have learned how to cure/prevent less favourable factors that natural selection would previously have worked on. I often hear people saying that we have effectively removed ourself from natural selection but I don't think that can ever happen. It will just work with a lesser effect.


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## enlightenment (Dec 14, 2006)

Craig Mackay said:


> Things is though, that these people such as Usain Bolt have spent a huge portion of their life training for such activities. The average Joe is not as fit and strong as they used to be and as Dan says the increase in average lifespan is mostly down to medical advances. *We have learned how to get the most from our bodies through excercise, medicines and a better understanding of human biology* and have learned how to cure/prevent less favourable factors that natural selection would previously have worked on. I often hear people saying that we have effectively removed ourself from natural selection but I don't think that can ever happen. It will just work with a lesser effect.


And this will go on.

Imagine what we will be capable of in 50 yrs?

Would be exciting times, imo.

And all from the intelligence of man.

A 'mental evolutionary process'?


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## GRB (Jan 24, 2008)

enlightenment said:


> How about the eyes of T's?
> 
> Most are apparently near blind.
> 
> ...


This reminds me of the oft quoted creationist arguement: "What use is half an eye?"

When you think about it, having a functional eye, even if it is nearly blind, is probably more use than not having one. Even being able to descern light from dark has its uses, even if it simply identifies possible hides (dark bits) sooner than they could be identified with long trichobothria or setae.


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## Mutley.100 (Nov 3, 2008)

enlightenment said:


> And this will go on.
> 
> Imagine what we will be capable of in 50 yrs?
> 
> ...



Bring on bionics .


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## enlightenment (Dec 14, 2006)

Mutley.100 said:


> Bring on bionics .


And advances in therapeutic cloning, stem cell research, etc...


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## enlightenment (Dec 14, 2006)

GRB said:


> When you think about it, having a functional eye, even if it is nearly blind, is probably more use than not having one.


But not as good as having at least one that has excellent vision.

So many eyes on a T, and all of them operate poorly.

Very.

Perhaps there was a time when they used their vision more?


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## Craig Mackay (Feb 2, 2009)

enlightenment said:


> A 'mental evolutionary process'?


Not really in my opinion as this is more of a cognitive process as we learn from the successes and failures of our predecessors and can apply the knowledge the human race has built up over the years. We will always continue to learn and develop new ideas regardless of brain size/power etc and as such newer and more effective technology will result.



GRB said:


> This reminds me of the oft quoted creationist arguement: "What use is half an eye?"


Argh, irreducible complexity! doesn't it just reek of ignorance? I have a creationist that comes to my door every so often touting this as proof of intelligent design and when I explain the way basic eyes could evolve he looks at me with a blank face then asks "do you not think that is far less likely than an there being an intelligent designer?". My answer is always the same.


GRB said:


> When you think about it, having a functional eye, even if it is nearly blind, is probably more use than not having one. Even being able to descern light from dark has its uses, even if it simply identifies possible hides (dark bits) sooner than they could be identified with long trichobothria or setae.


Precisely


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## Craig Mackay (Feb 2, 2009)

enlightenment said:


> Perhaps there was a time when they used their vision more?


Probably unlikely. As Grant has just put forward even poor eyes are better than none. Spiders have so many other senses that aid their survival that they don't need better "vision" than they have. I think sometimes we are overly guilty of anthropomorphising spiders (and all creatures) and assuming that because we have great vision it would be an advantage to every organism. Some creatures just don't need it and if they continue to be suucessful without then I see no reason why they would have had it in the past or would gain it in the future.


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## enlightenment (Dec 14, 2006)

Craig Mackay said:


> Probably unlikely. As Grant has just put forward even poor eyes are better than none. Spiders have so many other senses that aid their survival that they don't need better "vision" than they have. I think sometimes we are overly guilty of anthropomorphising spiders (and all creatures) and assuming that because we have great vision it would be an advantage to every organism. Some creatures just don't need it and if they continue to be suucessful without then I see no reason why they would have had it in the past or would gain it in the future.


Well, I am just thinking that with so many eyes, perhaps there _was_ a time when their environment was somehow different, causing them to have more of a need for an optical sense, than they have now?

Rather like the appendix.

It probably served a function, once upon a time, yet no more.

Maybe in time, the appendix will fade altogether?


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## Charlottie (Oct 4, 2008)

enlightenment said:


> Well, I am just thinking that with so many eyes, perhaps there _was_ a time when their environment was somehow different, causing them to have more of a need for an optical sense, than they have now?
> 
> Rather like the appendix.
> 
> ...


I think the apendix was used to help digest grass but im not too sure, there is a small chance that in time it may fade all together. but i have just quickly googled it and found (Re: what was the appendix used for?) here the guy goes on to say that it can be found in almost every mammel have an apendix and that i could be used to control bacteria levels in the large intestine. But it could be a unrealiable source.


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## enlightenment (Dec 14, 2006)

YouTube - 4 scorpions eating a spider!

Check that!

:gasp:


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## Mutley.100 (Nov 3, 2008)

enlightenment said:


> YouTube - 4 scorpions eating a spider!
> 
> Check that!
> 
> :gasp:


But what's it got to do with evolution ?


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## enlightenment (Dec 14, 2006)

Mutley.100 said:


> But what's it got to do with evolution ?


Feck all.

:Na_Na_Na_Na:


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## GRB (Jan 24, 2008)

enlightenment said:


> Well, I am just thinking that with so many eyes, perhaps there _was_ a time when their environment was somehow different, causing them to have more of a need for an optical sense, than they have now?
> 
> Rather like the appendix.
> 
> ...



The costs of evolving powerful vision are high - it's not just the eyes, but the cognition to understand and interpret the visual signal that is also needed. 

Also, you are comparing two different evolutionary artifacts; the appendix is a retained ancestral feature shared amongst the mammalia, whereas tarantula eyes are still functional despite their apparent lack of functionality. 

Their eyes are probably relicts from a time where ancestral chelicerate organisms (possibly similar to trigonotarbids?) which had eyes (harking back from a time where even simple ocelli represented a super weapon for predators) evolved them, and they were simply retained. If you look at the Chelicerata as a whole, they all have similar eye structure (barring some cave dwelling species who have lost the secondarily). Even the Salticids, which have quite good eyesight have a similar structure, albeit greatly enhanced in size (and likely cognition), eg _Portia_).

You could essentially view the eyes of tarantulas as an inherited "base level" which was never under any strong selection to improve sufficiently, whereas other groups with more active hunting techniques would benefit from improved resolution. 

Of course, this is just my take on them; Arthropod basal evolution is somewhat complex and open to many interpretations, well above my current knowledge!


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## enlightenment (Dec 14, 2006)

GRB said:


> The costs of evolving powerful vision are high - it's not just the eyes, but the cognition to understand and interpret the visual signal that is also needed.
> 
> Also, you are comparing two different evolutionary artifacts; the appendix is a retained ancestral feature shared amongst the mammalia, whereas tarantula eyes are still functional despite their apparent lack of functionality.
> 
> ...


Interesting stuff again - thanks.

I tell you what would be cool.

If there were websites that permitted us to see the world as a T (or even a housefly), would see the world.

Ever came across anything like that, Grant?

Steve


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## GRB (Jan 24, 2008)

enlightenment said:


> Interesting stuff again - thanks.
> 
> I tell you what would be cool.
> 
> ...


Unfortunately not, although I'd rather see like a fly than a tarantula 

Then again, I'd rather _be _a tarantula than a fly...:lol2:


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## Charlottie (Oct 4, 2008)

enlightenment said:


> Interesting stuff again - thanks.
> 
> I tell you what would be cool.
> 
> ...


you get some sort of tube that has got of different segments so you see things similar to a fly i think... but they arent that good! interesting tho hehe


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## enlightenment (Dec 14, 2006)

Charlottie said:


> you get some sort of tube that has got of different segments so you see things similar to a fly i think... but they arent that good! interesting tho hehe


Really?

Do you have any links?

x


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## enlightenment (Dec 14, 2006)

GRB said:


> Then again, I'd rather _be _a tarantula than a fly...:lol2:


Ah, but Grant, think of all the peeps who have fecked you off.

You could vomit on their food. :lol2:

_*Anyone seen the Acid House Trilogy?*_


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## Charlottie (Oct 4, 2008)

enlightenment said:


> Really?
> 
> Do you have any links?
> 
> x


I remember something like them when i was a kid .. will try and find something like it, i know you cans till get ones but you can only see a background they have put in.. off to have a look now hehe


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## enlightenment (Dec 14, 2006)

Charlottie said:


> I remember something like them when i was a kid .. will try and find something like it, i know you cans till get ones but you can only see a background they have put in.. off to have a look now hehe


Please do - :no1:

It's not one of those kalidiscope things, is it?

Sorry for spelling, I am really tired tonight


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## invertasnakes (Feb 1, 2009)

Hi guys, just thought I'd upload this. For the OP....its already happened....just put this on YT.

YouTube - Spiders hunting in packs


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## enlightenment (Dec 14, 2006)

invertasnakes said:


> Hi guys, just thought I'd upload this. For the OP....its already happened....just put this on YT.
> 
> YouTube - Spiders hunting in packs


Incredible footage.

They worked more like an ant colony.


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## Charlottie (Oct 4, 2008)

enlightenment said:


> Please do - :no1:
> 
> It's not one of those kalidiscope things, is it?
> 
> Sorry for spelling, I am really tired tonight


Well I didnt know the name of it! hehe so thats why i having struglling to find any and yes they are them, im sure i have sen sure which are just clear though! =/ ... :lol2:


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## enlightenment (Dec 14, 2006)

Charlottie said:


> Well I didnt know the name of it! hehe so thats why i having struglling to find any and yes they are them, im sure i have sen sure which are just clear though! =/ ... :lol2:


:whip: I just_ knew_ it would be one of them - :lol2:


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## _TiMiSdRuNk_ (Aug 27, 2008)

I found something on youtube all about your question.....

YouTube - Spiders hunting in packs

Enjoy


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## Charlottie (Oct 4, 2008)

enlightenment said:


> :whip: I just_ knew_ it would be one of them - :lol2:


Hehe!! sorry... 



_TiMiSdRuNk_ said:


> I found something on youtube all about your question.....
> 
> YouTube - Spiders hunting in packs
> 
> Enjoy


Afaird someone already beat you to it!


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## _TiMiSdRuNk_ (Aug 27, 2008)

Oh that'll teach me to not browse post to quickly!:lol2:


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