I can really get behind the whole micro-evolution thing, hell micro-evolution is all around us. But I have a hard time making the jump to macro.

Evolution is developing and strengthening the desirable traits while diminishing and eliminating undesirable and useless traits. So while I can understand why parronts develop a larger beak to crack nuts I don't get how a limbless species is supposed to develop limbs.

I've been told that some nub showed up one day via a mutation or defect and evolved into a working arm. Woah! But wait, shouldn't the nub have been a useless trait and bred out of the population before it could become desirable? Or am I to believe that the mutation was a fully functional limb from birth?

Is the explination that it wasn't undesirable so the nubby animals got to keep breeding and the nub just got bigger over time? Seems like it would become a burdon long before it ever became a useful functioning limb in that scenario.

I'm certainly not attempting to disprove evolution here, just trying to explain a plot hole that maybe I don't have enough info on.

Darwin, Buddha or God?

Take a pinch of each, apply to an open mind and smile.

Quote:
Hamlet:
"There are more things in heaven and earth, Horatio,
Than are dreamt of in your philosophy".

To my mind, in order of credibility, Darwin, Buddha, God.

But what do I know? :-)

Many products of evolution evolved serving other purposes on the way to how they're used now.

For a while people thought it would be incredibly clever argument against evolution to say that eye, which doesn't work if you remove any part of it, proves that evolution doesn't work. Until someone pointed out that evolution isn't like playing with Legos, building things bit by bit over time.

Some theorize that light-sensing cells that led to capability to sense brightness and from there on small change at a time to more useful capability if imagery we have now, started out as a light-sensitive protein structure in bacteria that aided them in their digestion.

As for arms, imagine crude fins or flippers sea creatures would have to allow them to control their movement. Obviously natural selection would prefer bigger, stronger, more controllable flippers that allow the creature to hunt it's pray better, faster and with less effort, while allowing it to escape from its own predators better. For land animals, the basics of movement are the same, as are the goals; feeding and escaping from dangers. Being able to climb to a tree gets you away from crocodiles. Being able to use your limbs to handle food is an advantage. And so on.

Not necessarily. Much of it is trial and error, with lots of random mutations that might be detrimental, beneficial or neither. Some mutations may seem benign or useless, until changing environment suddenly means this mutation makes or breaks an individual/species. (IMHO, this is why evolution is a mix of about 10% phygrad and 90% punkeek)

Populations don't breed toward some master "desirable species" plan. There is no plan, evolution doesn't work that way. There is no way to say "this mutation is desirable but this one is not," because it all depends on the environment in which the organism lives.

So just because a limb-nub was useless, doesn't mean it's undesirable and will be "bred out." It just may be benign, or useful for another purpose at first(the ladies might find it hot, for example).


This isn't a "plot hole" in the theory. While there are lots of questions left to be answerd regarding evolution, I don't think this is a big one. We, scientists, know that mutations aren't always beneficial or detrimental or benign, they might just "be" as there is no "master plan" to which a species is trying to evolve. In addition, the "fittest" do not always necessarily survive and the survivors are not necessarily the "fittest."
If you get a chance, read S.J.Gould's Wonderful Life. It's about the Burgess Shale, and discusses evolution and mutations in light of the strange flora and fauna at Burgess, and how fitness to one environment might not guarantee long-term species survival.

Fins and flippers are limbs but I get what you mean. The light sensitivity proteins made more sense to me though thanks.

I didn't mean an evolutionary plot just a personal plot hole in my mental mapping of evolution.

This.


Michael Behe claimed that "irreducibly complex" systems are unable to be produced trough evolution. Irreducibly complex system means something that is composed of multiple, interacting parts, and removal of any of those would cause system to cease from functioning. As an example he gave bacterial flagella, which is kind of like an outboard motor built out of proteins, complete with a propeller, drive shaft and a motor.

If evolution was Lego-building, this might hold some water. But even while it's not, bacterial flagella outlines my earlier remark. You remove part of the outboard motor, it ceases to function as a motor. What's left isn't useless though - it's now a functional secretory system. So it's likely that what evolved as a secretory system, through a mutation and ever so slight change, turned into a propulsion system - which obviously gave the bacteria an evolutionary edge.

Also:
Intelligent Design Society of Kansas

See the selfish gene theory.
If a gene complex causes impotency, it can still survive with a variety of tricks.
Hey, it can be even helpful in some types of species. A gene complex that stops the reproduction if completely present is absolutely helpful at species where the 2 parents are not enough to raise the offspring.
Some species, humans included have high level of altruism, gays in these species can help accumulate goods, while not taking out any for their kids.

The gene of homosexuality might even be something that is inside everyone, activated by some environmental trigger.

If overpopulation triggered homosexuality, lots of problems would be naturally solved.
Well maybe it can be triggered artificially...
and we have a new weapon...

Sort of on this theme, and how "bad" genes can get through.

Sometimes, being a carrier of a gene, but not expressing that gene, can be beneficial.

An example is Cystic Fibrosis. It would be expected that through natural selection, CF would have been eliminated. Up until the 50's, people with CF died in childhood. It's only lately that medicine has advanced enough so people with CF could have children.

But being a carrier of CF was (is) good. Basically, it let you survive Cholera and Typhoid, resulting in quite a high (1 in 25) instance of carriers today.

I'm sure there are other "bad" genes out there that do that.

Also, regarding homosexuality, some studies indicate that homosexual behaviour benefits groups and relatives rather than individuals. For example, one study indicated that homosexuals devote more time to their nieces and nephews, promoting their own genes in bodies of others.

Another study suggested that homosexual genes might have some other benefits (buy one, get one free kind of deal), such as boosting fertility of women.

i have mixed beliefs. i think there is a higher power that got things started: God - who made the big bang, and sometimes interferes ... but mostly things just interact and evolve.

like me making soup!

i also think mammals, at least have souls that carry our karma. something to explain why life is so unfair.

Most rejection of evolutionary theory is based on common misunderstandings of it. However, Creationists cannot say the same for their own mythology when they are confronted with the scientific evidence.

hm... I guess I'm against Evolution. I mean it says that we evolved from monkeys, fish, and further on.. but who started it? why? Like how did we come into what we are and why? What's our purpose in existence?

Nothing to add I guess

nvrmnd :)

Wow, it's 2009 and we're still having a debate on evolution?

One would have thought the Scopes trial in 1926 would have settled it.

Did you go DerAlt?

No, he was at his retirement party.

I'm against evolution too. It's making my hair turn grey.

:D :D

I think I was still evolving from the monkey portion of the debate.

DL:

May a diseased monkey fondle your nether parts.

Already did, I called him dad though :(