Evolution: FALSIFY IT!

Before I get started, I have to make the point that the vast majority of mutations - at least in metazoans (and I never really paid attention to the rest) - are NOT harmful or beneficial: the degenerate nature of the genetic code (64 amino acid codons, 20 or so amino acids) means that the vast majority of mutations are silent. This is particularly true when you consider that the most common errors in DNA replication (the most common cause of mutations, after all) are subtitutions of pyrimidines for pyrimidines, or purines for purines (one of the two), and the nature of the genetic code leaves particular room for this sort of mutation (all this is in protein coding genes only).

Anyway, moving rapidly on: the one idea that I find very surprising that creationists never use is the evolution of wings in insects: the wings are a complex outgrowth of blood vessels and relatively rigid membranes that is not homologous to any structure I am aware of in pre-winged insects (e.g. silverfish), and depends for its function on being above a fairly large size AND being linked via (also novel) connections to leg muscles.

The argument that I would hypothesize that an intelligent creationist, whether "young earth" or in favour of "intelligent design", would make is that such a structure consists of sufficient elements - none of which on their own allow flight - that its spontaneous arisal is extremely improbable, and, as several of these elements could perceivable be costly to any individual forming them, they must have occurred with a purpose, or end point - that is, the completed insect wing.

My hypothesis to suggest that the insect wing does not require a creator points to the early invasion of land by insects relative to other animal groups, and also to the status of the most primitive known winged insects (dragonflies) as top predators:

stage 1: predatory insect exists in an environment which, unlike the sea from which it arose, is of a changeable temperature. Being early colonists, predatory insect itself suffers little predation, and a more important challenge to them is that their body temperature is frequently lower than optimal when high activity is required, or higher than optimal for survival. Any individuals capable of regulating blood flow through extremities would be capable of better temperature regulation, and would, if they arose, be relatively successful.

stage 2: Increasing the surface area for temperature regulation allows this to be done more rapidly. In particular, any blood-vessel rich outgrowths could be favoured. Over time these could become more specialised to allow for variable temperature responses (e.g. blood-vessel rich outgrowths could be angled to maximise heat intake from the sun, or blood flow to them minimised to reduce heat loss). Some mechanism for moving these structures - or alternatively some mechanism for generating metabolic heat (as wing muscles are currently used in bumblebees to allow them to go out on cold mornings) would allow insects to move bodily fluids through the veins more efficiently, improving temperature regulation.

Stage 3: gliding for environmental navigation or predator escape - eventually, everything gets its own predators, even through cannibalism, and so being able to jump off your perch and get several metres head start on the one chasing you is obviously going to be a good thing.

Stage 4: powered flight is merely an improvement upon gliding.

I suppose I may have made and burned a straw man, but the alternative is coursework, and that's never fun.

Ok, it seems odd that there are so many people still opposed to evolution, keep acting as if it's a religion etc (odd, why do religious people think making evolution a religion is a bad thing?), but nobody has really tried to turn this argument into a proper falsification of evolution.

reply to post by madnessinmysoul


I resent that comment! I did my best (in my last post) to argue against evolution. It just makes overpowering sense, so I didn't do very well.

reply to post by TheWill


I imagine you twirling a Dali mustache while saying:

"Bah! Foiled by facts and evidence again!"

to yourself after that post.

Of course, that's because you're clearly in possession of sense of humor.

So plenty of people still seem to disagree with Evolution on here, but I've yet to see any proper falsification of the theory.

Come on, please someone try taking a crack at it.

Originally posted by madnessinmysoul
reply to post by Blarneystoner

 

Well, that's your choice at the end of the day. And nobody (except creationists) says that the two are mutually exclusive. Evolution and theism can coexist. Ken Miller is a biologist who defended evolution in the Dover trial, he is also a devout Catholic.

If that's your position, then I'm assuming Evolution and Ancient Astronaut Theory could also coexist.

reply to post by SquirrelNutz


Well...it would create a regress. The "Ancient Astronauts" would have to have evolved themselves. Of course, there's nothing to show that humanity didn't evolve or that we received any external help culturally or technologically (though that last issue is one for a discussion of things other than biology).

I mean, we could have had life seeded onto Earth, even though that's not what's under discussion.

What's here to be discussed is whether or not evolution happens. So far, nobody has really attempted to falsify it.

Originally posted by madnessinmysoul
reply to post by SquirrelNutz

 

What's here to be discussed is whether or not evolution happens. So far, nobody has really attempted to falsify it.

Nor will I. Evolution certainly happens.

(I don't think my detrators in that other thread acknowledge this)

reply to post by Badgered1


Why would there be hermit crabs when 'normal' crabs abound with shells of their own.


Umm since they have the need, why did the hermit crab not evolve into a normal crab?

reply to post by habfan1968


That's an easy one.

There's a niche, it was filled. Hermit crabs do not require proper shells because there isn't a selective pressure to force them to have regular shells, they survive just fine scavenging discarded shells from other animals.

reply to post by habfan1968


Oh dear.

It seems you have misunderstood evolution as a concept and applied the dreaded teleology.

You do not do something in evolution because you have to. If a selective pressure arrives, you cope with it - somehow - or you go extinct.

Please also note that hermit crabs are not particularly close to "normal" crabs within the crustacea.

Hermit crabs have soft bodies. If these soft bodies are exposed, the hermit crab is vulnerable to predation.

So, we have our selection pressure: predation of exposed soft bodies.

Responses: 1) keep exposing soft body. Result = extinction
2) cover soft body. Result = not extinction
3) stop having soft body. Result = not extinction.

Two alternative responses would have allowed them to persist. The mutations necessary to strengthen the exoskeleton of the vulnerable parts would probably be to more conserved sections of the genome, and so DNA repair mechanisms would limit the rate at which such mututions would arise, and if they don't arise, they can't go to fixation (going to fixation = becoming common to all surviving members of the population through breeding). Changes in behaviour (finding a shell to wear on days out) do not necessarily require mutations, and where they do are generally less dangerous (cancer/embryonic failure etc) and are thus less likely to be subject to DNA repair mechanisms (read: mututions are more likely to be passed on).

Further adaptions of hermit crabs to keeping their tenders inside a shell may have occurred after they started doing so. Please note that pistol shrimps spend a large part of their day hiding inside holes - including shells, sometimes - and it might be that hermit crabs simply started taking the shell with them, allowing them to have a fuller, more productive day.

reply to post by madnessinmysoul


scavenging for a discarded shell goes against the entire notion of evolution, previous generations of hermit crabs know they need shells, why have they not grown their own?

reply to post by habfan1968

Originally posted by habfan1968
scavenging for a discarded shell goes against the entire notion of evolution,

Nope, it really doesn't. It's entirely similar to the concept of finding food instead of producing your own.

previous generations of hermit crabs know they need shells,

They don't 'know' anything in their DNA.

why have they not grown their own?

Simple answer? No mutation has provided the required mechanism to grow shells.

Well, I haven't looked into the genetics of it, but here's a possibility:

Most likely, sometime in their evolutionary history hermit crabs lost the gene that forms a hard shell. It was either selectively beneficial or neutral, so it persisted. This most likely didn't happen early on. It was fairly recent, at a point where discarded shells in their habitat were common enough for them to scavenge.

I don't see how an oddity of marine life which is entirely consistent with evolution (they aren't dying off because of their lack of grown shells) falsifies evolution.

reply to post by madnessinmysoul



You will notice i like to keep things simple
The process you have described as evolution has not affected this Hermit Crab for some reason, according to wiki this crab has been around millions of years, surely enough time to develop it's own shell. As Will has pointed out, having a hard shell to protect it's softer side = survival of the species. I fail to see how evolution has helped this little guy out at all. Just because it has adapted does not mean it has evolved.

Originally posted by habfan1968
reply to post by madnessinmysoul

 

scavenging for a discarded shell goes against the entire notion of evolution, previous generations of hermit crabs know they need shells, why have they not grown their own?

By the way, use of the word discarded - keep hermit crabs sometime, feed them well, but don't put any spare shells in there. You'll soon see just how discarded a shell needs to be for them to move in.

I am going to explain the evolution of giraffes to you in the light of two different explanations of inheritence. One - now rejected - is primarily attributed to Lamarck, the other is essentially Darwinian (although it relies on Mendelian principles).

Lamarck's giraffes started out with short necks, along with everything else on the acacia scrub. Soon, there was very little in the way of foliage at close to the ground, so giraffes started stretching their necks up towards the leaves that remained higher in the trees, and in response, their children were born with longer necks.

In Darwinian inheritance, using the same model (although the body of evidence suggests that giraffe's necks are more about winning fights than reaching leaves), the giraffes, having a certain amount of genetic variation, have necks of different lengths. When they run out of food close to the ground, those with longer necks can reach slightly above every else, and so it takes them longer to starve to death, in which time, they have more babies than those who starved to death first.

Eventually, the longer-necked giraffes become common, but then they are in heavy competition with one another for the leaves that they can reach, so if a mutation happens to arise which gives one giraffe a slightly longer necks again, that individuals who can reach higher will live longer and have more babies.

And so it goes. This process comes down to survival of the fittest (Although survival of the satisficient is a more appropriate description) and underlies modern evolutionary thought. You don't choose to evolve. If you are fit, you have babies, if you are unfit, you die childless. Those who are fit thus contribute more to the next generation.

EDIT:

You may notice that I said hiding the soft part works just as well at leading to survival as developing hard parts. Both hard-bottomed crabs and bottom-hiding crabs would live - in fact, because mollusc shells are typically harder than crustacean shells (in the ocean), hermit crabs are less vulnerable to predation than "normal" crabs, and are thus often more readily seen.

Also, that something has adapted DOES mean that it has evolved. Acclimatisation is what you call it when an individual, within its lifetime, responds to a selection pressure. Adaptation, on the other hand, is change over generations.

reply to post by habfan1968


Yes, but there seems to be no specific selective pressure against not growing a shell and they seem to grow at a nice rate when they can simply discard their scavenged shell.

The simple fact is that there's always more than one way around things, and these crustaceans have found a different method.

Originally posted by habfan1968
The process you have described as evolution has not affected this Hermit Crab for some reason, according to wiki this crab has been around millions of years, surely enough time to develop it's own shell. As Will has pointed out, having a hard shell to protect it's softer side = survival of the species. I fail to see how evolution has helped this little guy out at all. Just because it has adapted does not mean it has evolved.

Whe lifeforms evolve, they often improve, but evolution does not mean improvement.
Evolution is not a force, it's a process by which life-forms change genetically and pass those changes onto their descendants.

If the changes aid the organism in passing on its genes, those genes are more likely to exist in the future population. If the changes handicap the passing on of genes, those genes are less likely to exist in the future population.

Survival is a gamble. Genetic mutation can have no effect, or can weight the dice one way of another.

Is a hermit crab more likely than a shelled crab to survive, just as likely or less likely?
That, and a bit of luck, are all that matter.

There is no perfection being aimed for, no pinnacle to be reached.
The theory of evolution is nothing but a description of this process whereby genetic information mutates and gets passed on to affect future generations.

Well, it looks like plenty of people on here still disagree with evolution, but I still don't see any good reason for it. Can someone please provide proper justification for not believing in evolution?

The Platypus: Why would God make it?
The Platypus: Why as it evolved to look...the way it does?

You see, the platypus is a very mysterious creature. Maybe some argument against creationism, as well as evolution? I don't have one, but if somebody would like to explain to me how such a monster could have evolved to its' surrounding, I'd welcome it...

reply to post by BrandonTsia


Having never encountered more than the mounted skeleton/ stuffed skin of a platypus (although I plan to move to Oz one day and then I will encounter them very regularly, whether they like it or not), I am going to have to make this argument from phylogeny.

1) the body is convergent with semi-aquatic mammals such as the beaver, so that's easy enough - a flattened tail helps you swim, thick fur is generally good, webbed feet are the general adaptation for swimming (although the coots do it with freakishly enlarged scales rather than webs), and all of those work on a modular basis - so easy enough to get to.

2) the bill. All extant monotremes (i.e. the platypus and the multiple echidnas) have no teeth. While we cannot be certain, from the fossil record, whether they have both independently lost teeth or if it is ancestral. My immediate assumption is that it's ancestral.

With the aquatic lifestyle that platypods have had quite a while (Cretaceous origins, if I'm not mistaken) to get used to, a toothless mouth is fine for catching slow-moving soft-bodied prey, but if you want to tackle the faster or harder-bodied animals, you're going to need to get a couple of adaptations. A beak is a decent alternative to teeth, so if you already had a beak-like mouth (the echidnas do, so probably ancestral), you'd have a much better start when you first took to the water.

For the breadth of the beak, there's two that I could suggest: 1) a broad bill is one way of being good at efficiently catching small prey such as shrimp (like a spoonbill's beak, in that sense), or 2) the platypus has, unless I'm mistaken, some sort of electro-sensory abilities to its bill. If this arose prior to the broad bill, it would have been useful for detecting when prey was in the area, but not great for telling where it was. any broadening or flattening of the bill would increase your potential to detect the direction that your prey is in, and so would be selected for (fatter platypods can lay more eggs, produce more milk to sustain those eggs, and are generally better equipped to survive times of hardship).

So, beaver-like body is convergent, bill is (in my opinion) an ancestral constraint with adaptations to make it more effective for their aquatic lifestyle. Also handy for strengthening riverside burrows, I've no doubt.

How they lost their teeth in the first place is easiest to explain with an echidna-type animal. Most of the anteaters have few (or no) teeth, and pangolins/aardvarks (in afrotheria) have lost theirs independently of the giant anteaters/tamanduas (in xenarthra).

Any good?