How does the creative process of Biological Evolution work?

Question

In order for nature to go from microbes to man, there needs to be new information. Where does this new information come from?

It is understood that Evolution basically involves three elements. Natural selection, genetic mutation, and time. The problem for Evolution, is that none of those three elements are creative. Natural selection is basically just a pruning process. It selects from what is there and advantageous, and prunes off what is deleterious to the organism as far as its fitness.

Genetic mutation is just errors in replication. So it creates nothing. It simply degrades. We have no new information, just an erroneous replication, and degradation of what was there before.

That is still true of gene duplication. We have an error that repeats the same information/genes. So we have two copies of something but there is still no new information.

This brings us to the second problem. What mechanism or process of nature/Evolution, carries out the instructions. What I mean by this, is that it essentially has to work like a computer. If I want my computer to have a more advanced program, I need to input new information, and its often codified in the form of say a disk, or installation file.

What is the equivalent of this installation file for Evolution?

For example. Say I'm a cephalopod. And I'm getting environmental pressure from predators and I want, or need, to advance my defenses, so I want to built some spikes on a hard outer shell. Where does the cephalopod get the new information, or rather, instructions, to know how to do this new feature?

Answer 1

Your basic problem is indeed a fundamental misunderstanding of how DNA and by extension its evolution works. First of all, there is no such thing as "correct" or "error", there are only changes, some of them are better for the individual and some are worse. You also have a basic misunderstanding of the concept of information. An error does not decrease the amount of information, it just alters that information. For example, consider this sentence:

The book is read

Say I make a simple error when I transcribe it:

The book is red

The two statements contain the same amount of information. Nothing has been lost, only changed. But that change created new information. Now what if I try a different change:

The book is rled

Now, this one is nonsensical, indeed, but how does that translate into DNA?

The computer analogy is a bad one. Programming languages have a very specific set of rules and anything outside those rules results in an error. For example, while this is a perfectly valid statement in many scripting languages:

print "Hello World"

This one is not:

priint "Hello World"

That, however, is not the way that DNA works. DNA is read in words of three characters, the codons. Every single possible combination of those characters actually has a meaning. Therefore, a mutation like that above which would decrease the information content of the sentence (here, the gene) is not possible. Let's quantify. The DNA sequence consists of a long series of chemicals, commonly known as A, C, T and G. Since these are read in "words" of three "letters", this means you have:

$$4^{3} = 64$$

64 possible combinations. Of these 64, 61 are words with a specific meaning and 3, the STOP codons, are punctuation marks, full stops if you will. In other words, all possible combinations of letters have meaning in DNA.

Because all possible 3-letter combinations have meaning, no change will affect the information content of the "sentence". All it can do is change it. Now, changing the information can indeed result in "sentences" that make no sense. In the DNA world, this most often results in what are known as deleterious mutations. These happen all the time, but the result is usually a dead individual. Those with such mutations are not even born (speaking of mammals).

However, other mutations, such as the change from read to red that I mentioned before, can give rise to a change of meaning, this change, if it turns out that it makes the individual carrying it more likely to reproduce, will spread across the population and will be selected for. That is how new traits can arise.

In closing, another point that you have misunderstood is that evolution is not a path from the least to the most complex. In many ways it is the inverse. In fact, by any measure that counts, bacteria are far more "evolved" than humans for the very simple reason that the only way you can measure evolution is in terms of numbers of generations. Think of evolution as happening every time a species reproduces, this means that bacteria have had orders of magnitude more time to evolve than mammals have. Still, this is a useless comparison which is why nobody compares species by how "evolved" they are. For a discussion on that, have a look here.

Answer 2

Your question, I'm afraid, betrays a deep misunderstanding of evolution.

Genetic mutation is just errors in replication. So it creates nothing. It simply degrades.

This is patently false. The vast majority of mutations are "errors", in that they produce a less fit organism. But once in a while, a mutation will confer an advantage, rather than an disadvantage. This, I suppose, is where "new information" comes from, though I would not use those terms. Your metaphor with software is not very accurate. If you want to "evolve" a piece of software through evolution, you do not insert new functionality into the source code. Instead, you would make a number of copies of the source code, each with a small, random alteration. Then you make the software available to all. The version that is most highly used on the market is then taken and the process is repeated. But good software is not developed in this way, for reasons that I hope are obvious.

I would highly recommend reading "The Selfish Gene" or "The Extended Phenotype" by Richard Dawkins.

Answer 3

It's seems to me you forget something pretty important about evolution : it has nothing to do with improvement. All living organisms have the exact same time of evolution as they all derive from a common ancestor. They simply evolved through different paths, that's what explain the biodiversity we can observe today and no organism is better than others, not even human.

New functions are not created just like that, because a species need it. To take your cephalopod's example : if there's pressure from predators, they won't simply grow spikes in order to protect themselves. However, if mutations (one or many) appear in the DNA sequence that make spikes instead of, say, skin, then this particular cephalopod will have better chances of surviving than others and so, better chances to reproduce and pass his new genes.

Mutations do not necessarily imply degradation -just as the los of one function is not necessarily a degradation. Every organs appeared thanks to mutations and / or duplications. For example, the humans' ability to see colors is due to 3 types of pigments (blue, red, green) named opsine S (blue), opsine M (green), opsine L (red). You add rhodopsine which is sensible to light to see clearly. If you study a mouse's eye, you'll only find 2 opsines + rhodophsine. Scientists have been able to recreate evolution's story : you start with an ancestral gene for opsine. The gene is duplicated and the copy is translocated on another chromosome. You now have 2 copies of the gene on 2 different chromosomes. They both mutate as mutations occur all of the time. You end up with 2 new genes. Then, duplication will happen again (no particular reason). You now have 4 genes, identical two by two. Three genes stay where they are, one of them is translocated on another chromosome and they'll all mutate. You finally get 4 genes on 3 different chromosomes (opsine M, L, S and rhodopsine). New genes and new ability appeared thanks to mutation, duplication and translocation. It just took millions of years of evolution and probably an impressive amount of tests.

As Shigeta wrote, everything potentially exists. Some of the possibilities have been discovered, some have not. Evolution applies on hundreds millions of years and billions of living organisms and it process accidents after accidents. If what appears is selected, it stays, if not, it disappears.

Answer 4

Where does the information come from?

From the environment, and the previous history of interactions in that environment. The process of evolution can be viewed as an undirected search for "good" solutions (i.e. those that better support replication) to problems presented by the environment.

There is a large amount of information (in the information-theory sense) in a differentiated environment.

Note that information content of the whole system is preserved when this happens. Partly the misunderstanding of "information is being created" is not seeing what a huge resource of information (in the same sense used with information theory that says it may not be created or destroyed) is available from the environment. It is many many orders of magnitude greater than anything stored in genetic codes.

Answer 5

It is understood that Evolution basically involves three elements. Natural selection, genetic mutation, and time. The problem for Evolution, is that none of those three elements are creative.

They absolutely are creative in that they create something new. Mutation introduces random errors, some of which may never have existed before in that combination of genes. Now usually errors are bad, and natural selection prunes the result, but every once in a while, you accidentally stumble upon something new that provides an advantage, and now natural selection means it gets kept and passed on to the next generation.

So on their own, it might seem that mutation doesn't add information and natural selection doesn't create anything new, but together, natural selection adds information to the randomness of mutation: it selects what works and what doesn't.

Imagine you're rolling a die (warning! simplified analogies don't accurately reflect the complexities of evolution). What are the chances of you rolling 10 sixes in a row? Vanishingly small of course. But that's not what evolution does. What it does is in every phase (generation), it rolls 10 dice, and only keeps the sixes. What is the chance of getting a six in every phase now? Quite a lot bigger. All through randomness and selection.

(In fact, have you ever played Yahtzee? How can you get the right patterns there if you're just rolling dice and selecting some of them?)

Take your analogy with the sentence "Make an eye that is compound". A mutation might turn that into "Make an eyye that is compound" which is useless. But another mutation might turn it into "Bake an eye that is compound" which is grammatically correct though nonsensical. Yet another mutation might create "Make an eyr that is compound", and if that one happens to survive a generation, you might get "Make an ear that is compound".

Thing is, there are a lot of mutations. Really a lot. Most of them have no measurable effect. Of the remainder, the vast majority breaks something, which means they automatically get weeded out by natural selection. A tiny fraction accidentally adds something useful. If you look at any single mutation, it's impossible to imagine how that could ever result in anything useful, but there's a lot of them. Every generation again, over thousands and millions of years, and eventually, those very few positive mutations start to add up.

It's impossible to fully grasp how evolution can introduce totally new species without first grasping the enormous time scale on which evolution works. And we humans are limited beings and bad at truly understanding such enormous scales. But it clearly works. We can see the results all around us. We can run simulations on computers that show that the process really does work. I consider it one of God's greatest miracles (warning! personal opinion might not reflect those of others).

Answer 6

I think this is a little like writing a book. The most common advice is for aspiring writers to write every day and write a decent amount.

Evolution creates by testing everything against its fitness - its ability to survive and reproduce. If something is advantageous, it stays in the corpus of genes and genetic solutions to problems. If something is not working well or even not as well, it may be lost and forgotten - dropped out of the gene pool.

So just as a writer may throw out 90% of their writing to get to their published novel, 90+% of biological experiments are thrown out and don't have long lasting repercussions in the biosphere. its probably more like 99.9999999% really.

The creation of information you are talking about are all inherent in the physical universe. Just as every computer program is potentially existant in the laws of logic and mathematics, all the potential mechanical and informational and configurational advantages of living things are embedded in the physical laws in which they operate. It is not an event of creation, but an event of discovery when a new biological function appears.

Answer 7

evolution means unrolling http://www.etymonline.com/index.php?term=evolution

Now if you imagine a tree with one root then the stem rolls out, branches roll out twigs and leaves roll out etc. Same with the roots on the other and to balance it out.

And that's it. Evolution does not happen in a vacuum. It happens in and together with an environment. If the environment changes and you have unrolled something that helps you cope with that change then you can continue to procreate so that your offspring also have a chance to test any eventual new unrollings in the constantly changing environment. If they die then the branch or twig that was unrolled is cut off and might unroll again later and be cut off again until maybe, just maybe some sunlight will reach it and it can survive. Until night falls again.

Answer 8

Another important point about evolution is, that rhere are many, many small steps - not huge leaps. E.g. going from a bacteria to something with four legs in one step will not happen - that is simply too much change at once, and it's probabillity is close to zero. But small steps happen all the time - if we take your example with a cephalopod: Imagine that there are some individual cephalopods who have a harder skin. Without predatory pressure this is next to useless: the cephalopod are investing energy on something which brings no benefit. So they are less fit and will probably have fewer offspring than the original ones. Now a predator kill many soft-skinned cephalopods but sometimes fails to eat their harder skinned brethren. The hard-skin variant will producre more offspring and theier genes spread. Then the next round happens: cephalopods with the hard skin might have another mutation which hardens the shell even more - or the predators might get better teeth. But be aware that this most not happen: maybe no variant with harder skin exists or the genetic error is not present at the time and the whole race simply dies - this happens a lot. Look at dinosaurs or the polar bear (is under pressure because the polar ice melts) etc.

Some fun fact: since each step is random and has a low probabillity, you willl never get the same reult twice. If you start the evoluation again, the world would look completely different because the steps would look different.