…and this is a 
An exercise for the readers
Category: Evolution
Posted on: March 5, 2008 9:23 AM, by PZ Myers
I and a diverse group of people got a question in email, one that we are supposed to answer in a single sentence. The question is,
What is evolution?
You know, Ernst Mayr wrote a whole book to answer that question on a simple level, and I'm supposed to have the hubris to answer that in one sentence? OK, knowing full well that it is grossly inadequate, here's my short answer:
Evolution is a well-confirmed process of biological change that produces diversity and coherent functionality by a variety of natural mechanisms.
Go ahead, you people try to answer it in one sentence in the comments. It's harder than it looks, especially since I feel the itch to expand each word into a lecture.
By the way, when I say this question was sent to a diverse group of people, I mean a diverse group of people. One of them was the author of this book, and another was from this site, and you can imagine what their answers were. (Sorry, they were sent out with some expectation of confidentiality, so I can't tell you them. Maybe they'll notice all the traffic to their websites and share it with us.)
Comments
A change in allele frequencies over time in a population.
Posted by: prettyinpink | March 5, 2008 9:29 AM
Evolution is the historical and present natural development of life on this planet and the scientific description of these processes.
Posted by: Gustaf Sjöblom | March 5, 2008 9:29 AM
mechanism responsible for the diversity and function of life as a natural phenomenon.
Posted by: AN | March 5, 2008 9:36 AM
Just "Change". Originally, used by Albrecht von Haller to describe the "unrolling" of an embryo. Darwin didn't use the word until 1872. Now, it's extrapolated to mean "Change", whether biological or not...
Posted by: PeteK | March 5, 2008 9:39 AM
Evolution is the accumulation of mutations resulting in heritable traits, and acompanying fixation of those traits in populations over time.
Posted by: Becca | March 5, 2008 9:39 AM
descent with modification.
seems to me that this was once put forward as the definition, like e=mc^2 its strength is in the brevity.
Posted by: gingerbeard | March 5, 2008 9:39 AM
Evolution is the process of natural selection acting on random variation within a population, which in the long term gives rise to new species by purely natural processes.
Posted by: Cat Faber | March 5, 2008 9:39 AM
I'm going with this:
Evolution is the gradual change and diversification of kinds of living organisms.
If I get a second sentence, I'll add:
Biologists believe that all modern organism diversity is a result of evolution.
I'm ready to defend what I included and what I left out, but the assignment did not ask for a lecture.
Posted by: ACW | March 5, 2008 9:42 AM
PZ - just write a whole book as a single run-on sentence (with parenthetical examples). After all, you never said that the person indicated a word limit.
Posted by: Umlud | March 5, 2008 9:46 AM
Evolution is the observed change, over time, of living things in response to the selective pressures of their environments and the consequent differing developmental expressions of their genetic makeup, along with occasional random mutations.
Posted by: Hairhead | March 5, 2008 9:46 AM
Reality.
Posted by: Satcomguy | March 5, 2008 9:49 AM
Leon Lederman (physicist and Nobel Laureate) once suggested (tongue-in-cheek) that the ultimate goal of physics was to explain the universe by means of an equation succinct enough to fit on a T-shirt. Richard Dawkins replied, regarding evolution:
"Life results from the non-random survival of randomly varying replicators"
I have yet to find a better or more succinct explanation of evolution.
Posted by: Elf | March 5, 2008 9:50 AM
Whatever sentence you choose, I think it needs to include some reference to heritability.
Posted by: chezjake | March 5, 2008 9:50 AM
The snappy version (#6) is definitely good for a quick comeback. For a longer form, I'd go for:
"Living things reproduce, their offspring are like their parents but not identical to them, and not all of the offspring survive, and so over time populations of living things change."
I think that gets the phenomenon and the mechanism quite neatly. Modelled on this:
"[These laws, taken in the largest sense, being] Growth with Reproduction; Inheritance which is almost implied by reproduction; Variability from the indirect and direct action of the external conditions of life, and from use and disuse; a Ratio of Increase so high as to lead to a Struggle for Life, and as a consequence to Natural Selection, entailing Divergence of Character and the Extinction of less-improved forms."
By a Mr. C. Darwin, who put it quite nicely, within the very generous Victorian standards of what constitutes "one sentence."
Posted by: Stephen Wells | March 5, 2008 9:51 AM
Okay, the Dawkins version is pretty snappy :)
Posted by: Stephen Wells | March 5, 2008 9:53 AM
I think it's a mistake to include mutation and natural selection in a definition of evolution. These are mechanisms whereby evolution is brought about, but they are not evolution itself. If we discovered that there were other processes that caused biological change over time, or even (this being science, after all) that the whole paradigm of natural selection was wrong, this wouldn't force us to find some new word to describe what we now call evolution, any more than we need to use a word other than evolution when discussing Lamarck.
I like gingerbeard's answer, which is short and to the point.
Posted by: noncarborundum | March 5, 2008 9:55 AM
The minimal definition of evolution is ..
The truly shocking thing is how many believers in evolution get it wrong. Unfortunately, that includes you PZ. Two of the absolutely essential features of any definition of evolution are: (1) it requires permanent genetic changes and (2) it is populations, not individuals, that evolve. Both of these restrictions are missing from your definition.
What this means is that there are lots of things covered by your definition that do not fit into the scientific definition of evolution. I'll leave it to your readers to come up with a list of such changes.
Posted by: Larry Moran | March 5, 2008 9:55 AM
Evolution: The observed fact that the genetic makeup of populations of organisms (the gene pool) changes, over time (evolves).
(The 'Theory of Evolution' explains how.)
Posted by: DuckPhup | March 5, 2008 9:58 AM
Evolution is a process of gradual accumulated change.
I take it we are talking about evolution in general and not just the evolution of species (social evolution, economic evolution, political evolution etc).
Posted by: reason | March 5, 2008 10:02 AM
Slightly improved:
Evolution is a well-confirmed process of well-confirmed biological change that produces well-confirmed diversity and well-confirmed coherent functionality by a well-confirmed variety of well-confirmed natural mechanisms.
Posted by: CalGeorge | March 5, 2008 10:03 AM
Interesting that everyone jumped to the specific Biology definition. My dictionary has: 1. any process of formation or growth; development.
Posted by: Taz | March 5, 2008 10:04 AM
I always liked "descent with modification" but I think the word needs to be wrested from the hands of those who would make it into some sort of "general algorithm" - that's the point where people stop doing science and become annoying - so I'm going with "descent with HERITABLE modification IN BIOLOGY, YOU MORON (ALL NATURAL, NO JESUS!!!)."
Posted by: poke | March 5, 2008 10:07 AM
I heard Dawkins define it one time as: The non-random differential survival of randomly varying genes.
You're right though, the urge to elaborate is strong.
Posted by: Evan | March 5, 2008 10:07 AM
@17 I wouldnt be so quick to call people wrong. You sound like a douche bag. PZ's definition is broad, along with many others.
Posted by: An | March 5, 2008 10:08 AM
The definitions that only refer to life are a bit limited. I work with evolutionary algorithms, and evolution can describe any variable population of individuals with heritable traits who distribution changes over time. Anything from designs of chairs to radio antennae to doormats can be evolved.
The thing I don't like about Dawkins' definition is that it implies that survival is always non-random, which it isn't.
Posted by: Derek James | March 5, 2008 10:09 AM
Evolution is the solution when engaged in interlocution about what put stunted willows in the Aleutians.
Posted by: Monsignor Henry Clay | March 5, 2008 10:10 AM
Evolution is 'God's gift' to atheists.
Posted by: Bharat | March 5, 2008 10:13 AM
Ok. IANA BioMajor, but here goes: *deep breath*
Evolution: The process by which heritable changes in individual organisms in a population gradually propagate through that population when those changes are proven, by means of natural selection, not to be detrimental to the survival and reproductive viability of the organism.
Posted by: Kseniya | March 5, 2008 10:14 AM
"Evolution is the scintifically-confirmed process by which new species arise and by which change occurs within species; evolution occurs via random mutation, natural selection, and other processes."
I hope semi-colons are legal.
Posted by: Ric | March 5, 2008 10:14 AM
Well, you're going to be a bit broad brush if you're trying to sum the whole thing up in one sentence! How about:
The process of genetic change within populations over time in response to their biological and physical environment?
Posted by: Lilly de Lure | March 5, 2008 10:15 AM
Evolution at any scale (from the microscopic to the galactic) is the the progression (following dumb mathematical laws) from old forms to new forms, sometimes with changes in complexity as well.
(This definition has the advantage of covering evolution in the chemical, biological, psychological, and stellar realms of study.)
Posted by: Terry Walker | March 5, 2008 10:17 AM
Evolution: Better than "goddidit", because it's real.
Posted by: zer0 | March 5, 2008 10:24 AM
Thanks to prions and such, I'm not so eager to talk about "allele frequencies", but here goes:
Evolution is the well-confirmed process by which successive generations of replicators change their characteristics over time, prominent components of which include the random variation of heritable traits and the differential survival of some variations over others.
Posted by: Blake Stacey | March 5, 2008 10:25 AM
Evolution is the observed phenominon of changes in biological lineages through both short and extended periods of time, as well as a collection of scientific theories that account for the observed changes at levels ranging from morphological observations in the fossile record, to molecular structures observable in the laboratory and through phylogentic comparisons.
Posted by: wade | March 5, 2008 10:26 AM
CalGeorge @ 20 Yes, but is it well confirmed?
*quickly ducks behind internet*
Cheers,
Ray
Posted by: Ray | March 5, 2008 10:28 AM
That which is discussed in Mayr's book.
Posted by: JC | March 5, 2008 10:30 AM
regarding #32, prions don't evolve.
Based on the linked post, a cross species prion may catalyze the misfolding of related prions in a new host, sometimes with reduced efficiency. Prions harvested from the new host will be genetically derived from that host (different AA sequence in most cases, though highly similar) and so be perhaps more efficient at producing prion desease in that host. No magic at all. The question of efficiency at catalyzing a misfolding cascade may not be one of structural efficiency but evasion of host defense against foreign epitopes. Hope that helps.
Posted by: wade | March 5, 2008 10:33 AM
Evolution is God's sketching pad :-p
Posted by: Sam | March 5, 2008 10:34 AM
Easy:
Evolution is a film starring David Duchovny.
Posted by: Andrew | March 5, 2008 10:35 AM
My one-sentence definition on evolution:
Evolution is the biological theory that postulates that various types of living things have their origin in other pre-existing types and that the distinguishable differences are due to modifications in success generations.
Posted by: Corey Schlueter | March 5, 2008 10:36 AM
OK, Larry, what if I tweak it a bit:
Evolution is a well-confirmed process of biological change that produces heritable diversity and coherent functionality in populations by a variety of natural mechanisms.
Posted by: PZ Myers | March 5, 2008 10:37 AM
The answer to the ultimate question about life, the universe and, you know, everything ...
Posted by: Douglas Adams | March 5, 2008 10:37 AM
... Well it beats 42
Posted by: douglas admas | March 5, 2008 10:38 AM
The extraction of a mathematical root.
Posted by: Thony C. | March 5, 2008 10:40 AM
Evolution is a process that occurs over time whereby, ideally, the most fit species propagate and diversify.
Posted by: Jeb, FCD | March 5, 2008 10:40 AM
Evolution: it's what's for dinner. (alternately: "Evolution: the other white meat")
just kidding.
Evolution is the process through which selective environmental, predatory, and other pressures augment or diminish the survival of random genetic mutations, giving rise to genetic diversity and speciation.
Posted by: Aaron | March 5, 2008 10:41 AM
Do you still kick your dog?
Posted by: Branedy | March 5, 2008 10:41 AM
Evolution is the differential survival of replicators over time, by processes of mutation, reproduction, and environmental interaction.
Posted by: ennui | March 5, 2008 10:43 AM
Fairly complicated.
Posted by: Schwa | March 5, 2008 10:46 AM
The question neither infers nor implies biological evolution. As a result only a few of the comments have unbiased answers.
Posted by: bigjohn | March 5, 2008 10:48 AM
PZ,
I'd leave out the "well-confirmed." It has no place in a definition. I'm not arguing that evolution is not well-confirmed, but that its confirmedness does not define it. Even if there were no evidence whatsoever for evolution, the definition would not change.
Besides, it makes you look defensive. How can you be supreme squid overlord when you're being defensive?
Posted by: Hans | March 5, 2008 10:53 AM
Wade-- No, Im not familiar enough with prions to put Bartzs presentation into the right words, but different prions with different disease outcomes evolve in genetically identical organisms.
Posted by: ERV | March 5, 2008 10:53 AM
Evolution is everything that relgion opposes.
Posted by: Holbach | March 5, 2008 10:54 AM
Evolution is the reason why there is racism and genocide and war and crime and prostitution, all of which began in 1859.
Posted by: Mrs Tilton | March 5, 2008 10:55 AM
easy.
evolution is the natural process whereby the gods lost their sex organs.
also: orgies with 10 similarly beautiful women.
Posted by: kid bitzer | March 5, 2008 10:56 AM
It's not mine, but it's a classic:
"Evolution is a change from nohowish, untalkaboutable, all-alikeness, to a somehowish and in-general-talkaboutable not-all-alikeness, by continuous somethingelseifications, and sticktogetherations"
Posted by: windy | March 5, 2008 10:59 AM
Hmm. That is like someone requesting a one sentence description of gravitation.
What would one describe, the basic phenomena ("attracting masses"), the basic definition ("gravitation is a process that results in a mass giving acceleration in a test mass"), the process ("massenergy tells spacetime how to curve, and spacetime tells massenergy how to move"), or the current theory (Einstein's field equations)?
Considering the audience I would go for the basic phenomena ("heritable changes") instead of a basic definition ("evolution is a process that results in heritable changes in a population spread over many generations", or "descent with modification" for short).
"Evolution is the change and diversification of organisms over generations" sounds good to me, cribbing from ACW's answer.
Posted by: Torbjörn Larsson, OM | March 5, 2008 10:59 AM
Evolution is a change in populations over time, in which populations adapt to their surroundings, and diverge into different species.
I will admit that that is really two (or three) sentences stuck together. The more concise (but less explicit) version would be to cut it off at the first comma.
Of course, for conciseness, Gingerbeard has it down. "Descent with modification": one cannot get better than that. The only problem is that it borders on opacity to the uneducated -- although I imagine that most of our responses to that question would do so.
I agree with those that would keep details about evolutionary processes and materials (natural selection and genes, to name two big players in each respective game) out of the definition. Evolution is a stronger concept than any one example can show.
I would also point out that Darwin did in fact use the word "evolution" in the Origin -- or a form of it, but in its modern sense -- as the last word of the last sentence. I will defer to historians of science as to how much that influenced the usage of the term.
Posted by: Opisthokont | March 5, 2008 10:59 AM
Ahem!
What you guys said.
That was easy...
Posted by: xebecs | March 5, 2008 10:59 AM
The genetic definition is the best in one sense. Even diehard YEC can't argue that allele frequencies in a population don't change over time.
But of course that is not the sense that most people find evolution find controversial, and focusing on alleles doesn't address that.
The truth is that biologists need multiple definitions to handle the multiple senses in which evolution is used. As in:
1. a change in the frequency of an allele within a population
2. the sum of all genetic change within a population over time
3. the ongoing, dynamic interaction between a population's genome and it's environment
4. the large-scale patterns of change in the living world produced by evolutionary processes
Posted by: Scott Hatfield, OM | March 5, 2008 11:00 AM
Evolution is when a banana has sex with an orange, making a monkey that turns into a man over time, so why are there still fruit and monkeys?
Posted by: Behe | March 5, 2008 11:02 AM
Oddly enough I find this very reminiscent of a famous Jewish story.
Your response puts you in the role of Hillel, you just need to add "Go and study".Posted by: Jeff Alexander | March 5, 2008 11:04 AM
Mrs Tilton @ 53 No, substitute your word Evolution for
religion and the sentence and insanity is complete and to
the blatant point.
Posted by: Holbach | March 5, 2008 11:05 AM
Evolution is the observation observation that the diversity of living things is the product of descent with modification.
Natural selection is process by which the differential survival and reproduction of variants in a population results in a net change in the phenotype of the descendant populations.
Or, shorter form:
Evolution = nobody looks exactly like their parents.
Natural Selection = nobody looks exactly like their siblings, either, and it's a dog-eat-dog world out there, so use the traits that Nature gave you.
Posted by: Thomas R. Holtz, Jr. | March 5, 2008 11:13 AM
Behe @ 59,
The monkeys are obviously still there because they are needed (in large numbers) to work the typewriters. As for the fruit - well, the monkeys have got to eat, no?
Posted by: Derek Huby | March 5, 2008 11:18 AM
The essential elements are: random change, reproduction, non-random selection. PZ's first attempt in the post left out the random and reproductive bits.
"Survival of the fittest accumulates random mutations to yield large-scale diversity after many generations"
Well, something like that, anyway :).
Posted by: Amit Joshi | March 5, 2008 11:21 AM
PZ, don't you think it's a bad idea to include "well-confirmed" in the *definition* of 'evolution'? I mean, wasn't evolution happening long before it was well-confirmed (which it now is)? Do you really want evolution to be well-confirmed *by definition*? If so, we're not really saying anything when we say that evolution is well-confirmed.
Again, what would you scientists do without us philosophers watching your backs? (Oh yeah, science.)
Posted by: Dustin | March 5, 2008 11:26 AM
Yes, that is why the common or Moran's definition is good, and why Dawkins' fails.
The same goes for a minimal definition of gravitation, for example. It is the duty of a theory and its descriptions of observed mechanisms to flesh out and fulfill the definition. For example, how much acceleration a mass will give to a test mass.
I would certainly use the definition in describing the phenomena elsewhere. But IMHO it is more informative and catchy to try to describe the process here.
Probably not, considering the audience. But there is confusion in that there isn't any reason to let a basic definition of a process exclude similar processes; it should be short, general and inclusive. It is, as I observed above, the (natural) task for a theory to exclude other processes.
The theory of evolution is about biological evolution, and for example genetic algorithm software will not exhibit all the mechanisms and other phenomena associated with biology. At least not yet.
Similarly to a basic definition of evolution, or the process of life as a population knows it, one can make a consistent definition of a living (individual) organism:
Note that this is also inclusive, so multicellulars, unicellulars, viruses, plasmids and other evolutionary elements can be included as soon as they have individual histories, as well as software if you wish.
Posted by: Torbjörn Larsson, OM | March 5, 2008 11:27 AM
Evoloution mean change over time.
The fossil record shows us that life has changed significantly over time with a general trend of increasing complexity.
Evoloutionary biology is the study of the natural processes by which these changes came about.
Posted by: Euan | March 5, 2008 11:33 AM
Differential selection among replicating replicators in response to a selective gradient.
So why are there still AYATOLLAHAS and POPES?
Posted by: mothra | March 5, 2008 11:33 AM
Living things have easily observable variation due to the presence of different alleles, generated by random mutation, necessarily resulting in some individuals being better adapted to their environment, and in some cases able to exploit new resources, which necessarily allows those individuals to reproduce faster, eventually dominating the population.
I think this sentence has the advantage of explaining how evolution works specifically, while arguing that it must be true. It seems to require a second sentence to explain speciation.
Posted by: Mark | March 5, 2008 11:33 AM
Jumpin' Jeezus!, from 'this book' ...give you a Biblical understanding of God's care and provision for HIS animals...
'His' animals goddam eat each other! Idiots!
Posted by: Richard Harris | March 5, 2008 11:38 AM
"Descent with modification" seconded (or thirded or whatever). The basic fact of evolution needs to be kept as simple as possible - you can flesh out the details in the theory.
People only really make natural selection into a "general algorithm", so far as I'm aware. And it seems to me such a move is justified wherever you have imperfect replicators with differential reproductive success and limited resources.
Posted by: Ginger Yellow | March 5, 2008 11:40 AM
Chance sifted.
Posted by: Derek | March 5, 2008 11:44 AM
I have still to read the referenced paper, but this raises a series of questions to this layman:
- This sentence seems to describe differential reproductive success of the misfolding in its current environment. The post claims that this adaptation (of the misfold) indeed happens over time. How is that not selection and adaptation?
- The mechanism of "variation" is AFAIU sourced by host variations of prion proteins. But isn't environmental sources for mutations allowed?
- I assume from the descriptions that it is the misfold that is the evolutionary element with independent lineage here, the evolving "organism". The prion protein itself is just the carrier, as a cell can be a carrier for a virus. As a virus undergoes changes during infection, is it a problem for an evolutionary description that the misfold induces a slightly different misfold of another protein when jumping the species barrier or when and if the host produces variations of the prion proteins?
Posted by: Torbjörn Larsson, OM | March 5, 2008 11:52 AM
Slight modification, not wishing to sound Lamarkian.
Evolution is the differential selection, as a function of a selective gradient, among randomly varying replicating replicators.
@17 If you tally up the responses of the sixteen prior to your post, the majority do meet the major points you posted. As Bugs would say: "What a Moran."
Posted by: mothra | March 5, 2008 11:52 AM
I like Darwin's comment about "Heredity (which is almost implied by reproduction)." Self-reproduction has to mean producing offspring _like yourself_, so inheritance is implicit there. Descent with modification really does capture the heart of it. Decorating it with mutation (one mechanism of variation, not the only one) and natural selection (one mechanism of filtering, not the only one) is superfluous until you get beyond sentence 1.
In fact, I'd even cut down my earlier suggestion in #14 to this:
"Living things reproduce, their offspring are like their parents but not identical to them, and so over time populations of living things change."
Posted by: Stephen Wells | March 5, 2008 12:02 PM
@Holbach,
Mrs. Tiltons' post was satire... go read her website. Most entertaining.
Posted by: Elf | March 5, 2008 12:03 PM
Evolution is the result of random changes in the order of nucleotides producing heritable differences between members of a population, and it is the process by which inherited traits that confer upon their possessor slight advantages in survival and/or reproduction are passed on to the next generation in greater measure than inherited traits that do not confer such advantages, so that any given generation of any given population is ever so slightly better adapted to its environment than the generation before, with the result that over exceedingly long periods of time (too long by several orders of magnitude to be observed in a laboratory setting and not completely observable in the fossil record due to the rarity of the conditions needed to create fossils, which means the 'microevolution' observed to occur over short periods of time is usually considered proven fact while the 'macroevolution' that occurs over millennia is debated), populations that began with identical gene frequencies and that live in differing environments end up with such different gene frequencies that a member of one population is no longer capable of producing fertile offspring with a member of another population, at which point the different populations are more accurately termed different species.
To all my English teachers who told me run-on sentences are bad: Take THAT.
Posted by: MercuryBlue | March 5, 2008 12:08 PM
Never mind, I believe I can answer that one myself.
Yes, it is a problem. The adapted misfold will not take its change to the next host organism. So yes, a more infectious misfold will spread through a population of hosts provided that the hosts produce the variations with some probability.
As it is, the misfold isn't independently evolving. Sorry, ERV (and Bartzs), I will now need some more convincing before accepting (misfolds of) prions as organisms.
But I have still to read the research.
Posted by: Torbjörn Larsson, OM | March 5, 2008 12:10 PM
ERV, continued sidebar on prions: prion particles are never pure. They can incorporate other cellular detritus, for instance peptides from degraded actin, To the extent that prion particles of altered composition recruit "same" structural elements to "crystallize" out and create a pathological state, more stable, thus more pathological and more endurable pathogens can evolve. There are reasonable arguments to support such a model but quality characterization of prion particles, especially of components present as sub-stoiciametric levels is very very challenging. The advantage of this model is it is far more mundane than invoking just prion protein structure for variant pathogenicity.
Posted by: wade | March 5, 2008 12:11 PM
Evolution makes sense.
ID does not.
Creationism = mythology.
See, it's easy! ;-)
Posted by: jfatz | March 5, 2008 12:11 PM
Evolution is a well-confirmed process of biological change that produces diversity and coherent functionality by a variety of natural mechanisms.
You got it right. Evolution involves both process (change over time) and mechanism (what causes the change).
As Gould correctly pointed out, the process is FACT but the mechanism is THEORY.
Neo-darwinism is a MECHANISM and can be described as an unsupported theory.
To conflate both PROCESS (FACT) and MECHANISM (THEORY) into the same package is irresponsible, disingenuous and down right fraudulent.
Intelligent design is a MECHANISM of evolution and has as much right to be considered as darwinism.
You can easily believe in both evolution AND intelligent design. Just ask the billions of catholics, jews, protestants and muslims who do.
Posted by: Dungeon Inhabitant | March 5, 2008 12:19 PM
I tend to go for "descent with modification" whenever this question comes up. Admittedly, it's not a very good one, but if the interlocutor is sharp enough all the repercussions of evolution become very clear in my experience.
Posted by: Daniel | March 5, 2008 12:19 PM
"Evolution is the change in the genetic makeup of a population over time."
It's a phenomenon, not a process, and there really should be a little more rigor in defining it. Otherwise the "theory of evolution" bleeds into the fact of evolution.
The theory of evolution by descent with modification is such a predominant and comprehensive explanation of the phenomenon of evolution that it is often called THE scientific theory of evolution. But even if the theory were overthrown tomorrow, evolution would still happen - scientists would just have a different explanation.
Posted by: Glazius | March 5, 2008 12:20 PM
Heredity.
Posted by: teacherninja | March 5, 2008 12:22 PM
Evolution is random variation tested then replicated.
Posted by: colluvial | March 5, 2008 12:22 PM
There is some confusion here between definition, 'minimal definition', and what evolution is.
Definitions are typically one sentence and are supposed to guide and/or explain word usage.
What something is is another matter altogether.
Posted by: Pete Dunkelberg | March 5, 2008 12:25 PM
Edited from #77, and others.
I believe it to be grammatically correct, recommended for use punishing someone for limiting you to one sentence.
Evolution, a process well-confirmed by biology and paleontology, is the action of natural selection, the process by which inherited traits that confer upon their possessor slight advantages in survival and/or reproduction are passed on to the next generation in greater measure (change in frequency) than inherited traits that do not confer such advantages, upon variation caused by mutation, random changes in the order of nucleotides (alleles) producing heritable differences between members of a population, so that any given generation of any given population is ever so slightly better adapted to its environment than the generation before, with the result that over exceedingly long periods of time (too long by several orders of magnitude to be observed in a laboratory setting and not completely observable in the fossil record due to the rarity of the conditions needed to create fossils, which means the 'microevolution' observed to occur over short periods of time is usually considered proven fact while the 'macroevolution' that occurs over millennia is debated by IDiots) occasionally speciation, when a population is divided into reproductively isolated populations ending up with such different gene frequencies that a member of one population is no longer capable of producing fertile offspring with a member of the other population, occurs.
Posted by: Mark | March 5, 2008 12:29 PM
Evolution is the process of energy & matter interacting with time.
.
Posted by: Jaycubed | March 5, 2008 12:30 PM
Mrs Tilton @ #53 I retract my comment at #61; I did
read your site and it is good stuff! Being such a staunch
hater of religion, I am unable, and probably unwilling to
recognize satire from sarcasm. I am always ready and
happy to express my opinions on insane religion, sometimes
at the expense of differentiation. Keep that site alive!
Posted by: Holbach | March 5, 2008 12:31 PM
Torbjörn, regards #73, 'misfolding' is scaffolded much like crystalization is seeded. Take reproduction out of the picture. But proteins misfold all the time and the cell cleans up after itself, or dies. When it dies, other cells clean up after it, or pick up the poisonous structures and die in turn. More stable structures are harder to clean up after. Beyond stability itself, the kinetics of recruiting new material matters. I'll leave the differential equations to others but repeat the note that prion particles are not pure.
Posted by: wade | March 5, 2008 12:31 PM
Okay, I don't have any new defintion, since others have already put it about the same way I would, but here's my 2 cents worth. Assuming it's biological evolution (which is what most people mean by evolution, really), I think it depends on the target audience. "Descent with modification" probably is the best, succint answer, but doesn't help when you're at a dinner party and trying to give a definition that people will actually understand. In that case, I'd go with something like Stephen Wells first defintion, even if it does hint at selection, which is only one of the mechanisms of evolution:
I also like Thomas R. Holtz's answer, similar to the above, but closer to the wording I used when explaining evolution to my 8 year old:
Posted by: