So, Lamarck was right after all. Do we owe him an apology?

[CraigD]

The other day, while I was at work,

I noticed a rather large garden spider building it's web.

That web was an engineering marvel to say the least!

…

I was wondering...how on God's green earth did it do that?

My best guess, based on various things I’ve read about spiders, is that they do it at least to some extent the way we would, via planning, trial-and-error, and learning, informed to a large degree by their sense of sight.

 

In general, spiders have good long-range vision, and have been shown capable of acquiring, remembering, planning, and acting upon this information. There’ve been many interesting tests of spiders’ web-making ability that support the idea that a lot of cognition – brain use – is involved, a couple of standouts being:

• Spiders taken into space aboard a spacecraft take a while to learn how to make large, neat webs in weightlessness
  
• Spiders given caffeine, LSD, and other drugs often can’t make neat webs at all.
  

(sources: NewScientist article “Portia labiata: the spider so smart it puts mammals to shame” and wikipedia article “spider web”)

 

This is pretty enticing to me, because the possibility of determining, on a neuron-by-neuron basis, precisely how a spider, which has on the order of 100,000 neurons, does this, seems more tractable than for an animal like a human, which has around 100,000,000,000.

 

Several of Don’s questions can be answered by patiently watching a spider make a web. One I can answer from direct observation:

Indeed, how did it get it's initial thread from one tree to the other?

I’ve seen this done 2 ways, by the same individual spider:

• She affixed a web strand to one tree (actually, a porch pillar), then extruded more web, hanging from the strand until the wind blew her into the second tree. She could take several minutes, waiting for the wind to shift to the right direction.
  
• She extruded a web strand while clinging to the first tree, until the wind carried it to the other tree, where it stuck.
  

In both cases, wind was important: in absolutely still air, neither would have worked. Only a very small breeze was needed, though, as both silk and spider are very light, and because their surface area, which determines the force of the wind on them, scales as the square root of their mass.

[Michaelangelica]

Spider silk probably deserves a thread all its own (pardon the pun)

 

Everone is trying to synthetise it

(What about enslaving thosands of spiders to work in a silk factory?)

Scientists are so enamored with spider silk because it has an “exceptional capacity to absorb kinetic energy” (Cunningham, 2007). Although it may not seem strong and tough from the vantage point of a human who easily can tear down a spider’s web, pound-for-pound, the silk from certain kinds of spiders is five times stronger than steel.

What’s more, it can stretch 30 percent farther than the stretchiest known nylon, and is twice as flexible. Scientists have discovered that spider silk can even stretch 40 percent beyond its original length without breaking. In fact, due to its amazing strength and flexibility, it has been said that you could stop a jumbo jet in mid-flight with a spider web made of silk only one centimeter thick.

. . .“spider silk” that could be used for countless things, including bulletproof vests, bridge suspension cables, and artificial tendons. Scientists especially covet the silk’s “exceptional capacity to absorb kinetic energy”

Apologetics Press - Exceptional Spider Silk

A lot of links here

ARACHNOLOGY - SPIDER SILK

but you are more on about the beauty and patterns-- are you not?

when spiders are on LSD, or in space the patterns can't be made.

BTW did they catch the spider that escaped on the ISS?

[CraigD]

Spider silk probably deserves a thread all its own (pardon the pun)

 

Everone is trying to synthetise it

(What about enslaving thosands of spiders to work in a silk factory?)

There’s a lot of interest in having large quantities of spider silk – one promising use is lightweight, flexible bullet-proof fabric – but AFAIK it’s not practical to harvest it from real spiders, because they simply don’t make enough of it. The only significant commercial venture into synthesizing spider silk of which I’m aware is Nexia’s “BioSteel”, though according to their website, they’ve given up on producing clothing and other large-size spider silk fabric. Nexia uses genetically engineered goats to produce tiny fibers of spider silk in their milk. We’ve discussed this a good bit at hypography, such as 13438, here, here, and here.

when spiders are on LSD, or in space the patterns can't be made.

AFAIK, the drug experiments on spiders (caffeine, as I recall, affected them about as severely as LSD) didn’t try repeatedly dosing them to see if spiders could learn to spin webs well while “high”. What’s significant in the space experiments, and my point in post #18, is that space spiders learned after only a few failed attempts to make reasonably good webs in weightlessness, indicating that more than just using a robot-like, instinctive ability, spiders are capable of learning and adapting to conditions never before encountered by their species, evidence that, despite their tiny brains, they’re amazingly mentally flexible. While space spider webs were not identical to normal ones – the major difference being that the thickness of the threads in the space webs was less uniform than normal – their second and subsequent attempts look at a glance pretty much normal.

BTW did they catch the spider that escaped on the ISS?

No, and I doubt they ever will.

 

For their size, spiders need a lot of liquid water, and lot of food, neither of which are easy to find in the nooks and crannies of a space station. Although they have a sort of “hypernation” ability, I think it most likely that the escaped ISS spider has died there. The other spider taken to the ISS was returned on STS-119 Saturday, 3/28/09 (see SPACE.com -- Spider May Have Survived Months in Space).

 

The survival rate for space spiders is pretty awful. The sort-lived (1973-1979, abandoned in 1974) US space station SkyLab hosted 2 garden spiders, both of whom died within days of their arrival, barely having time to spin a couple of decent webs. Too little planning for keeping the spiders alive appears to have resulted in both dieing of dehydration, a problem solved with the ISS spiders by keeping them (that is, one of the two of them) in a box with a large breeding population of flies. So, unless I’m ignoring some less-known Soviet/Russian space spiders, of 4 spiders who’ve flown in space, only 1 survived.

 

;) I actually saw the remains of one of the SkyLab spiders a couple of weeks ago on a visit to the Dulles Air & Space Museum, where she’s on display, along with a web, the box she flew in, and some other space miscellanea in an inconspicuous glass display case just behind the tail of the space shuttle Enterprise.

[Michaelangelica]

An interesting article I missed in New Scientist 12 July 2008 Strange Inheritance by Emma Young

Strange inheritance - 27 August 2008 - New Scientist

 

Emma talks about the teasing out of the actual mechanics of epigenetic changes.

Inside the nucleus, DNA is packaged around bundles of proteins called histones (Is this the name of a protein? ) .

These have tails that stick out from the core. Chemical modifications to these tails such as the absence of acetyl and methyl groups will affect gene expression.

Genes can also be silenced directly from enzymes that bind methyl groups onto the DNA

 

The RNAi system can also direct this activity, via small and largeRNAi strands.

 

One example she gives is of Queen bees

Ryszard Maleszka at ANU (Oz) have shown that epigenetic mechanisms create Queen bees. (!)

They used RNAi to silence a gene for methyltransferase an enzyme necessary for adding methyl groups to DNA in honeybee larvae. Most of these larvae emerged as Queens without ever having tasted Royal Jelly !! (Science DOI: 10.1126/science.1153069)

 

Emma gives many, many, other interesting examples of epigenetic change too.

The comment I liked was epigenetic changes can be easily reversed and drugs that influence methylation are now in early stage anti-cancer trials.

 

Epigenetics discoveries may have all sorts of amazing repercussions. For example

in agriculture

• rats exposed to the common crop fungicide vinclozolin in the womb were less fertile and had a higher than normal risk of developing cancer and kidney effects
  

mental health

• In schizophrenic-brain- post mortems there were epigenetic factors controlling the expression of 40 genes, especially those related to neural transmitters
  

Drug laws

• Male mice who had inhaled cocaine passed memory problems on to their pups.
  

Public health/ Obesity nutrition

• Men in Sweden who's paternal grandfathers had suffered a shortage of food between the ages of 9 and 12 lived longer than their peers
  
• Fathers who started smoking before age11; their sons -but not daughters-had a much higher average body mass at age of 9
  

Law

• Stress from child abuse made for epigenetic changes in brains.
  

Public policy

• If a pregnant woman's diet can affect her child's epigenetic marks; what about the now routine administration of foliate to pregnant woman (it reduces spinal cord defects)
  
• Yet foliate is a potent methyl donor.
  

So,. . . too much, or too little, food seems to affect gene expression for generations!

 

While the article is not online unless you or your organisation are subscribers, there were some follow up letters, some silly, some adding to what she had said, some silly and interesting

e.g.

Emma Young reports mild food restriction affecting the health of offspring (12 July, p 28). Research carried out by colleagues at La Trobe University shows that it also dramatically improves maternal behaviour in rats and that the young show a number of behavioural differences, including greater sexual activity - see, for example, DOI: 10.1016/j.physbeh.2007.06.018.

 

One striking finding is that while the mothers showed lower testosterone, the offspring showed higher testosterone and, in most cases, lower anxiety. This gives a curious twist to the finding that fetuses that experienced lower testosterone-to-oestrogen ratios in the womb, as measured by relative finger lengths, are more likely to grow up to be scientists and engineers (24 June 2000, p 32).

 

It follows that people who eat more moderately or restrict sexual activity as a result of religious beliefs, both likely to reduce testosterone, should be more likely to raise scientists and engineers. If this is correct, encouraging the teaching of intelligent design in schools may, ironically, be an effective way to increase scientific thinking in future generations, though direct biochemical intervention would probably work better.

 

We have found that even the smell of calorie-restricted rats has a similar effect to calorie restriction itself, although milder.

 

From Gill Wakley

Strange inheritance - 30 July 2008 - New Scientist

dDid you miss the thow away line at the end of that letter?

We have found that even the smell of calorie-restricted rats has a similar effect to calorie restriction itself, although milder.

 

The meme that it is 100% your fault you are fat is a very hard one to shift, despite the overwhelming amount of scientific evidences showing obesity has many, many causes.

The current obesity epidemic in the developed world should not be attributed to our parents or grandparents having gone through periods of having too little food. Our history shows that episodes of famine have been common and were not succeeded by epidemics of obesity. Obesity is due to behaviour - that of eating too much food compared with the expenditure of energy. It cannot be explained away by complaining that "My mother didn't have enough to eat".

 

Abergavenny, Monmouthshire, UK

some more silly letters here:-

Strange inheritance - 30 July 2008 - New Scientist

interesting- the historical baggage of this issue

http://www.newscientist.com/article/mg19926671.300-strange-inheritance.html

 

now we may need to add a whole new epigenetic layer to this below AHRRARGH!!

[Don Blazys]

An interesting experiment would be to allow a pair of rats food

only if they perform some specific task that is

sufficiently difficult and completely foreign to them,

(such as climbing a rope), then see if after a few generations,

the ability of their progeny to perform that particular task

shows a measurable improvement.

 

The baseball field at the school where I work is sometimes used as a

makeshift parking lot, which used to kill most of the grass.

However, over the past few years,

it seems that grass has somehow grown "accustomed"

to being crushed by the weight and singed by the hot mufflers

because the field no longer needs to be replanted every year!

 

Don.

[freeztar]

An interesting experiment would be to allow a pair of rats food

only if they perform some specific task that is

sufficiently difficult and completely foreign to them,

(such as climbing a rope), then see if after a few generations,

the ability of their progeny to perform that particular task

shows a measurable improvement.

 

Will this work?

 

YouTube - Judson University Rat - ladder maze http://www.youtube.com/watch?v=ttG7ulOUHtw

 

It's well known how to train mammals. Does this relate to progeny? Nope.

 

If it did, it would be well documented. If we've missed the evidence somehow, please, show it.

[Larv]

Will this work? It's well known how to train mammals. Does this relate to progeny? Nope.

But why couldn't the aptitude for learning be a matter of heritable genetics? Whatever is learned is not heritable, of course, but the ability to learn it certainly could be passed on to the progeny.

[Galapagos]

But why couldn't the aptitude for learning be a matter of heritable genetics? Whatever is learned is not heritable, of course, but the ability to learn it certainly could be passed on to the progeny.

 

This is known among biologists as The Baldwin Effect:

Baldwin effect - Wikipedia, the free encyclopedia

The Baldwin effect, also known as Baldwinian evolution or ontogenic evolution, is an early evolutionary theory put forward in 1896 in a paper "A New Factor in Evolution" by American psychologist James Mark Baldwin which proposes a mechanism for specific selection for general learning ability. Selected offspring would tend to have an increased capacity for learning new skills rather than being confined to genetically coded, relatively fixed abilities. In effect, it places emphasis on the fact that the sustained behavior of a species or group can shape the evolution of that species. The "Baldwin effect" is better understood in evo-devo literature as a scenario in which a character or trait change occurring in an organism as a result of its interaction with its environment becomes gradually assimilated into its developmental genetic/epigenetic repertoire (Simpson, 1953; Newman, 2002).

 

Again, this is Darwinian and not 'Lamarckian'. There are some other phenomenon in biology that happen to look like the inheritance of acquired traits, but are not. Another one is genetic assimilation.

 

As I stated in a previous post in this thread, it is important for the sake of historic accuracy not to equate anything that appears to be the inheritance of acquired traits with Lamarck's theory of evolution. Lamarck postulated ambiguous driving forces, envisioned an ever-escalating ladder of progress in evolution, and was not at all unique in his belief in inheritance of acquired characters(as Gould states in the article in the above linked post, entire volumes have been written tracing the history of the idea of acquired inheritance before Lamarck).

[Larv]

This is known among biologists as The Baldwin Effect:

The "Baldwin effect" is better understood in evo-devo literature as a scenario in which a character or trait change occurring in an organism as a result of its interaction with its environment becomes gradually assimilated into its developmental genetic/epigenetic repertoire (Simpson, 1953; Newman, 2002).

 

But why does there even need to be a Baldwin Effect, other than to serve the needs of evo-devo theorists? Why can’t it simple be a matter of genetic aptitude?

 

Look, if you want to bred dogs to learn tricks it’s much better to breed smart dogs with smart dogs. Their aptitude to learn tricks will be a matter of their genetic inheritance. There doesn't need to be a Baldwin Effect. A trick can be seen as a Dawkinsian extended phenotype. I suspect evo-devo-ists want to make something more of it.

[Don Blazys]

To freeztar,

 

Ouoting freeztar:

It's well known how to train mammals.

Does this relate to progeny? Nope.

 

If it did, it would be well documented.

If we've missed the evidence somehow, please, show it.

 

No evidence. Just an idea. A suggestion.

 

There is so much that we don't know. So many unanswered questions.

Why are African Americans who never even visited Africa better dancers

(generally speaking of course) than their European American counterparts?

Is it just a coincidence that dance is a much more prevalent aspect of

African culture than it is European culture?

 

Of course animals can be trained to do some pretty amazing tricks,

but here's the point that I'm making...

 

Now, if the rat in that video has brothers and sisters who were not trained,

then it would be interesting to continue training the progeny of the trained rat

while leaving the progeny of its untrained brothers and sisters untrained.

Then several generations later, stop all training and

put all the untrained progeny in an environment where

the aquisition of food would require skills similar to

what was learned by the trained ancestors.

 

It should then be easy to observe whether or not

the untrained progeny of the trained rats

turn out to be superior at performing the specific (and artificially necessitated)

tasks necessary to the aquisition of food.

 

I never heard of such an experiment being performed.

Have you?

 

Don.

[freeztar]

To freeztar,

 

Ouoting freeztar:

 

No evidence. Just an idea. A suggestion.

 

I can't help it, I'm looking for evidence. :phones:

 

There is so much that we don't know. So many unanswered questions.

 

Why would you say this?

Of course there are many unanswered questions. That is what Science is for!

Whether it is your intention or not, the implicit notion I got from your two sentences above was a feeling that you were expressing Science's inadequacies. Does our current knowledge crumble in the face of uncertainty? (Please excuse me if I've mis-judged you)

Why are African Americans who never even visited Africa better dancers

(generally speaking of course) than their European American counterparts?

Is it just a coincidence that dance is a much more prevalent aspect of

African culture than it is European culture?

First, that is a stereotype.

Second, you must show proof for such statements, per site rules.

 

I've known African American men to dance very poorly and I've seen Caucasion American men dance very well.

 

Of course animals can be trained to do some pretty amazing tricks,

but here's the point that I'm making...

 

Now, if the rat in that video has brothers and sisters who were not trained,

then it would be interesting to continue training the progeny of the trained rat

while leaving the progeny of its untrained brothers and sisters untrained.

Then several generations later, stop all training and

put all the untrained progeny in an environment where

the aquisition of food would require skills similar to

what was learned by the trained ancestors.

 

It should then be easy to observe whether or not

the untrained progeny of the trained rats

turn out to be superior at performing the specific (and artificially necessitated)

tasks necessary to the aquisition of food.

 

I never heard of such an experiment being performed.

Have you?

 

No, Don, I have not heard of such an experiment.

 

I would approve such an experiment, but I find it highly unlikely that it would be commissioned. The reason? It goes against mounds of experimental and observational evidence. Scientists have been training mammals for decades. I'm unaware of experimental data that shows anything similar to what you suggest. If I'm ignorant, please enlighten me! :D

[Don Blazys]

To: freeztar,

 

Quoting freeztar:

Whether it is your intention or not,

the implicit notion I got from your two sentences above was a feeling

that you were expressing Science's inadequacies.

Does our current knowledge crumble in the face of uncertainty?

(Please excuse me if I've mis-judged you)

 

Science is by no means perfect, but it is certainly more "adequate"

at explaining (or attempting to explain) the mysteries of life, this universe,

and existence in general than are all other methods and disciplines combined.

 

The history of science demonstrates that "current knowledge"

never crumbles in the face of uncertainty,

because the knowledge of truth is, by definition,

an understanding of well established and irrefutable facts.

 

However, conjectures and theories have indeed crumbled

in the face of new discoveries and observations, and quite often at that!

 

Quoting freeztar.

First, that is a stereotype.

Second, you must show proof for such statements, per site rules.

 

I've known African American men to dance very poorly and

I've seen Caucasion American men dance very well.

 

"Stereotypes" exist because there is usually sufficient evidence to indicate

that some trait is more prevalent in one group than it is another.

I've heard the old sayings that there are three kinds of lies,

(lies, damned lies, and statistics) and that by using statistics,

it is possible to "prove anything",... but I will venture to guess that

black basketball players outnumber white basketball players

by a rather substantial margin.

 

(Basketball and dance do indeed have many similar qualities and elements

and while I couldn't find the statistical data to prove that blacks are,

generally speaking, better dancers, I can easily prove that they are,

again, generally speaking, better basketball players.)

 

Why should this be?

Can Darwinism explain why one group of humans seems to

"inherently know" how to play basketball while another group doesn't ?

 

Don.

[mynah]

There is so much that we don't know. So many unanswered questions.

Why are African Americans who never even visited Africa better dancers

(generally speaking of course) than their European American counterparts?

Is it just a coincidence that dance is a much more prevalent aspect of

African culture than it is European culture?

I don't know that this is true - but people generally enjoy doing what they are good at more. If an unusually large percentage of people in a society carry genes that make it easier to master certain skills, these skills may well be taught more often than in other societies. (Obviously, other factors are involved as well: Some religions, for instance, frown on dancing, while others encourage ritual dancing. These religions are not necessarily native to all or most of the people who practise them.)

[Michaelangelica]

:esmoking: Bloody hell not another "nature of science" debate again.

Does some organisation, like The Templeton Foundation or Discovery Institute, pay people to wander about the net to bore science forums into submission?

[Don Blazys]

Black superiority in the arena of basketball is a fact!

The statistical evidence is simply overwhelming!

(Blacks comprise approximately 10% of the population in the U.S.

yet approximately 85% of the population in the NBA.)

 

Now, this phenomenon is either genetic, or epigenetic.

 

How is that "off topic"?

 

It's a perfectly valid (and interesting) question!

 

Moreover, it allows for a true debate

because no one really knows the answer.

 

Isn't that what we want in a good science forum?

 

Don.

[mynah]

Michaelangelica:

 

I believe the debate about Lamarckian inheritance is a very valid one. In brief, it is often forgotten that Lamarck did not have the findings of Darwin and Mendel at his disposal. The contributions of Lamarck were blighted by the doctrines of charlatans such as Trofim Lysenko, who - although well aware of Mendelian genetics - ignored them and promoted the heritability of acquired characters to such an extent that the Soviet economy suffered enormously and many peasants starved to death. Perhaps at least partly because of this, the contributions to non-Mendelian inheritance of brilliant scientists such as Barbara McClintock were downplayed for much too long. If this had not happened, we may have been much further down the road of understanding human inheritance.

 

Don Blazys: Blacks dominate basketball, but why? Is it because they are more likely to take up the sport, or that they have some innate genetic advantage? Why does India produce so many good mathematicians? Why are whites overrepresented among Nobel prize winners - and why are so many of them Jewish? Why are marathons mostly won by East Africans, and the shorter Olympic biggies by athletes of West African descent? Why do whites mostly win the swimming medals? Why do Chinese score highest in IQ tests?

 

I don't think there is one answer to all these questions...

[Larv]

...Blacks dominate basketball, but why? Is it because they are more likely to take up the sport, or that they have some innate genetic advantage? Why does India produce so many good mathematicians? Why are whites overrepresented among Nobel prize winners - and why are so many of them Jewish? Why are marathons mostly won by East Africans, and the shorter Olympic biggies by athletes of West African descent? Why do whites mostly win the swimming medals? Why do Chinese score highest in IQ tests?

 

I don't think there is one answer to all these questions...

Sorry for butting in here, but I simply don't understand why genetic predisposition doesn't explain the general trends observed above. We can always dicker over environmental factors, learned attributes, and other evo-devo distractions, but none of those things will be possible if the subject human being is not favorably endowed with genetic inheritance. (Environmental factors and learned attributes are not what kept Stephan Hawking out of the NBA.)