Filling in the gaps in evolution theory?

Question

Good camouflage - harder to find, long legs - harder to catch, evolution can be seen to work at the macro level, but what about the small stuff? Does every step by step incremental change towards some revised form necessarily evidence the theory, or does the theory need to be invoked in order to support its own underpinings (bootstraps?). The theory says every step towards a higher-evolved creature is driven by the natural selection driver and no other agent of change. I can't buy it because it cannot be demonstrated and it certainly seems unlikely - no more than a hypothetical crutch to help support the theory. The theory of evolution may be valid, I certainly accept the general principal, but I strongly suspect there are many strains of ongoing change in an evolving lifeform that, contrary to theory, cannot be demonstrated to provide any obvious benefit at the time they are adopted. They are assumed to do so because the theory says they must. Any thoughts/evidence on this?

Answer 1

Ronin has the right idea, here Endor, but let me give you a little more coverage.

Actually, "small stuff" has been observed often; there are, for example, bird and insect species which have adapted to changes in their environment, such as pollution from human sources.

But more dear to your heart -or your stomach, perhaps- is the "annual flu bug" which each year has researchers scurrying to find a "shot" that will help us defend against it. And of course, there's that nasty avian bug which scientists fear may jump across species to choose US as a host.

And we haven't even begun to talk about engineered plants, whose genes have been zapped in various ways to make bigger blooms, more disease resistant leaves, etc., etc. Forced evolution, if you will.

Point being, that in order for a "change" to pass from one generation to the next, something must happen at the genetic level in order to have something to pass along.

Although the very word "evolution" seems to imply "improvement," it ain't necessarily so. Evolution, taken as a whole, attempts to explain how "we," (meaning anything alive today) got here and got to be the way it is. But along the way, there were a lot of trial runs, as it were, that didn't pan out for one reason or another. They may have been "best of breed" by some measure of successful adaptation at their time -but died off when the rules of the game environmentally got changed.

The concept of being "more highly evolved" needs to be understood in terms of context of species history -as opposed to some value judgement such as "better." And so, humans, as more "highly evolved" than our predecessors at THIS point in history are not "better" or more "advanced" than apes -unless you think that being human is the best deal there is. Rather, homo sapiens sapiens are simply the latest successful adaptation of species stemming from the same branch of the tree as the apes. In fact, there is some evidence -and those who argue- that Cro-magnon "man" may have been more "highly evolved," than are we, if you take brain size as an indication. But good old CM didn't make it, some say, because at the time they walked, the presence of a big brain wasn't as important as what the Neanderthals had going for them. I'm not going to argue what made Neanderthal more adapted than CM, because a lot of people who are brighter and better informed than me are sucking down martinis at their convention's happy hour to argue that one out.

But what I'll try to convey is a way for a layperson to understand what -scientifically- is even meant by "evolutionary THEORY." The word, "theory" doesn't just mean an "idea" or "educated guess." Rather, in science, a "theory" is a systematic way of understanding a phenomenon that best fits with all the data known to be associated with the phenomenon. Gravity, strictly speaking, is still a "theory." Because theory is based on data -as opposed to being applied TO the data- it changes whenever the facts (data, information) changes or new material is discovered. The theory of evolution itself has evolved since Darwin and his ilk articulated it long ago -and continues to evolve as we speak.

It is true, or course, that as more data appears to support a theory, the theory itself achieves a sort of dominance as a means to explain new facts; and thus, the discovery of a million year old creature's skeleton who looks just like Donald Duck will be tested against what evolution may have to say about it. If the discovery doesn't fit with anything our theory tells us, that does not mean the theory is wrong. Why? Because we already KNOW it and every other theory is already "wrong" inasmuch as it is and shall forever be INCOMPLETE. And so, in the case of Donald Duck we need have several options. Is there any other evidence (facts, data) we have overlooked? Suppose that one week after discovering Donald, someone dug up the bones of a creature who looked like Walt Disney! Now, we see Donald a bit differently, perhaps. Another option is to keep the theory essentially in tact, but to re-arrange elements or arguments within the theory to see if we get a match to the data. There are other options, but finally we come to the "I dunno" answer and put the problem data up for review by everyone else in the hunt and wait for ideas, more theory modification or more data. This is sort of like discovering an important looking part left over from putting together your fancy new charcoal grill and wondering what its for. Then your 5 year old comes up one day, holding the part in one hand and pointing with the other, while you're grilling away, and says, "Does it go here?" indicating a hole where grease is dripping through all over your patio.

I've tried to be humorous here to suggest the process at work, but you can surely appreciate how the enormous and ever changing body of data with respect to evolution mean the process of resolving the place of unexpected data is pain-staking, time-consuming, difficult and even the stuff of heated argument. And THAT'S just among the scientists! Bottom line: you and anyone will rarely find simple, black and white answers in a theory whose subject matter is all about "shades of grey."

Add on to that the input of "creationists" and NOW you've really got a fight on your hands.

Hope this helps. You posed a GREAT question, intelligently worded and very stimulating.

Answer 2

> " I certainly accept the general principal, but I strongly suspect there are many strains of ongoing change in an evolving lifeform that, contrary to theory, cannot be demonstrated to provide any obvious benefit at the time they are adopted. "

Fair enough. But the burden is on you to find an example.
Many have tried.

You have correctly stated the basic theory (although you made a misstep when you used the word "higher" ... that is a human-centered error). You also may be missing the role that random, non-advantageous changes can have. Sometimes a mutation may produce some change that is neither advantageous nor disadvantageous (the different eye colors for example) ... such a mutation may just linger in the gene pool in small percentages for generations ... until one day a second mutation, or a change in the environment, or even a change in sexual preferences, causes that mutation to have some small advantage. However, your general description of the theory is correct ... that evolution is driven by small advantages (no matter how small).

And you have also conceded that the general principle is sound. This is precisely why we call things in science "theories" ... they are an explanatory system ... a set of general principles that seem to explain all the examples we have found. It is always a *practical* impossibility to prove that it holds for ALL examples ... so we keep examining possible counter-examples, and the more the theory holds, the stronger it becomes.

As an illustration, the theory of gravity says that all matter with mass is attracted to each other in ways that follow certain laws of behavior. It holds for an apple and the moon. It also seems to hold for pears, peaches, and cantelopes. And it explains the specific motions of the solar system bodies. There is no practical way to prove that the theory of gravity holds for all kinds of fruit, or all star-planet systems... we just *assume* it does. If you believe it doesn't, then the burden of proof falls on you to find an example ... some piece of fruit, or astronomical body that is *not* explained by the theory of gravity.

For the theory of evolution, many people have tried to find counter-examples. This is preciesly the claim of "irreducible complexity." However, what ID advocates do is to find a so-called counter-example, and then strut around triumphantly as if they have achieved their objective. In *every single case* presented so far, the theory of evolution can be shown to explain the structure in question. In other words, the "irreducible complexity" is shown to be quite reducible after all.

The eye, the flagellum, the venus flytrap, insect-flower systems, blood clotting, the ear, the heart, the egg, the cell, etc.

These are all great questions. But creationists and ID advocates ask the question as if the asking alone is sufficient to disprove evolution. It is not. It is also necessary to *listen to the answer*. If the evolution advocates can come up with a plausible answer for how evolution can explain the structure or system in question, then the intellectually honest thing to do would be to abandon that example and look for another.

Instead the creationists and ID advocates continue to bring up the same failed examples over and over. So these questions accumulate in the creationists arsenal as if they believed these arrows were really doing some damage to the evolutionists. But the evolutionists really are just thanking them for their trouble because each one actually *strengthens* the theory of evolution, because (as I said above) if a candidate counter-example is proposed, but found to be explainable by the theory, then it *strengthens* the theory.

So the creationists have yet to find the equivalent of the piece of fruit that defies the theory of gravity.

Answer 3

"The theory says every step towards a higher-evolved creature is driven by the natural selection driver and no other agent of change." Evolution is not progress. Organisms do not necessarily become better in any absolute sense over time, meaning that organisms do not become "higher-evolved." As for natural selection being the only agent of change, that is incorrect. Although natural selection is the most important, other mechanisms include mutation, genetic drift, and gene flow.

Mutation is random, natural selection is not. Some mutations may be beneficial, most are not. Natural selection tends to remove the less-fit individuals, allowing the more-fit individuals to survive and form a population of fit individuals over time. Keep in mind that evolution isn't progress, and that populations simply adapt to their current surroundings. A trait or strategy that is successful at one time may be unsuccessful at another.

Since your question is based on a faulty premise, I hope that this helps you understand evolution a little better. The link below is a good site to explore evolution further.

Answer 4

Well firstly, evolution is easy to see. Check up on peppered moths in England during the Industrial Revolution. Secondly, most evolutionary advances are small enough not to be noticed in fossil records. They could be all sorts of advantages that just do not leave an imprint such as a more efficient enzyme due to mutation. You can look at the human population as well. Due to our technological advances and communication, we've dampened our own natural selection. Sick infants live to become adults, the blind can function near normal lives, predators cannot sneak up behind the deaf and eat them. almost 50% of the world needs some form of eye correction, whether it be small or large and the number is growing. Before technology, most of those people would never have survived long enough to reproduce and pass on their genes.
Obviously, this is not 100% solid evidence and that's why it's still a theory. But it is a very strong theory and the more likely we have so far.

Answer 5

>The theory says every step towards a higher-evolved creature is driven by the natural selection driver and no other agent of change.

That's not strictly true. It is possible for a life form with inferior traits to still be successful if it just plain gets lucky. It is also possible for a mutation to occur which is better in most ways than its ancestors but worse in a few other ways. Natural selection is just what tends to happen ON AVERAGE.

Answer 6

There is a lot of evidence supporting evolution, and it has been observed in real time. However, for the most part the changes are very small and it takes a very long time for the differences to become apparent.
You should check out www.talkorigins.org and do a search for 'speciation' and 'transitional fossils' to see some of the many examples of evolution.

Also, you seem to think that evolution has some goal. It does not. Evolution does not have a goal or a target in mind. The changes happen. If they help or hurt, there is no intention behind them.

Answer 7

Evolution does not mean an increase in intelligence but a change within a species that increases survival rate, therfore propogation opportinities increase.

The theory does seem to fit in many cases, but survival is not only linked to selection. Massive and rapid environmental changes can dessimate a species allowing another species, or same species with a certain characteristic to take over, this is in no way survival of the fitist by selection, but luck.

Answer 8

You misunderstand:
"theory says every step towards a higher-evolved creature is driven by the natural selection driver and no other agent of change"
this is incorrect.
Random mutation occurs in every direction, larger body size, smaller, bigger brain, smaller, etc... Then natural selection, sexual selection, and other factors determine which of thes changes will propagate.

There are definitely times that certain parts of a body will change for no current purpose. One example of this is the coccyx in human beings. It really serves almot no function and is subject to more random change than "useful" parts. The number of vertebrae in the coccyx vary between different people. However the number in the neck is the same for almost all mammals.

These "spare" parts or redundancies are useful fodder for future change.

Answer 9

Evolution cannot be seen to have occured at the 'macro' level.
We do see change at the micro level - otherwise known as Natural Selection.

Neo-Darwinian Evolution is the hypothesis that animals can change into different kinds of animals by means of natural selection working on genetic mutations.
These alleged mutations need to add genetic information. However no such genetic mutation has ever been observed. Mutations are information neutral or lossy.
'But evolution is too slow to see' protest the evolutionists. Well then it's not observable and not worthy of being even called a theory. In any case, time is the enemy - mutations are resulting in the degradation of the gene pool - that is observable.

The claims of evolutionists are laid bare and easily refuted by the moderately diligent student.
Just search for your favourite evolutionary 'proof' here.
http://www.creationontheweb.org/

It is tragic that people (eg Nick above) are still claiming that peppered moths proves evolution!
It is not even natural selection, it is just a change in population of pale and dark moths. The famous photos were even faked.
Absolutely nothing to do with 'molecules-to-man' evolution.
Don't let yourself be decieved - check for yourself.
http://www.googlesyndicatedsearch.com/u/creationontheweb?q=peppered+moth&hl=en&lr=

Answer 10

Don't think of evolution as a simple gradient heading to perfection but rather as a chain of mountains. An adaption may get to the top of a foothill and stop rather than keep going down the valley and up to the next, higher, hilltop etc. The Blind Watchmaker by Richard Dawkins says it much better than I can