What is evolution?

[Micaiah]

What is evolution? How do evolutionists and Christians define and use the term? What about the meaning of abiogenesis and micro and macro evolution? Can any genetic change be considered evolution?

 

[seebs]

Oh, boy, not asking a small question here.

Abiogenesis is the question of how the first life forms came to be.

Evolution is mostly concerned with how life forms change, over many generations, to adapt to their environment.

As an example, if you gradually heat a petri dish with a culture of bacteria growing in it, you end up with a culture of bacteria which thrive at a higher temperature than the "original" culture did. That's evolution.

 

[lithium.]

Has this already been discussed here before like so many times? I'm sorry it's just i'm just so bored with the evolution threads right now (it's always the same thing).

 

[Pete Harcoff]

I typically see "micro" and "macro" evolution defined by biologists as:

microevolution - evolution within a species
macroevolution - evolution between species (in other words, evolution from one species to another)

Keep in mind, though, that there's no real difference between the two in terms of what is actually taking place (in other words, the mechanism for each, reproduction, genetic variation and selection, is exactly the same).


Now, creationists on the other hand, tend to define them more like this:

microevolution - evolution that has been directly observed and documented
macroevolution - any evolution that has not been directly observed and documented

Which leaves the creationists free to dismiss any inferred evolutionary pathways from things like, oh, the fossil record, genetics, etc.

 

[Jerry Smith]

Can any genetic change be considered evolution?

Any change in a population's gene distribution is considered evolution under neo-darwinian theory (NDT). Therefore, any genetic change that becomes fixed over time is considered evolution.

How do evolutionists and Christians define and use the term?

Evolutionists and Christians define the term as "change over time", although they sometimes use it in a more specific sense, along with concepts such as "common descent", and with theories like the NDT to explain the diversity of life on earth as the result of evolution over vast periods of time from a single population (or small group of populatins) of one-celled primitive organisms.

There are some exceptions to that statement, because there is a sect of Christians that are somewhat anti-science, known as "Creationists" who use all of the terms in unorthodox ways in a ploy to convince other Christians to abandon science and join their sect.

"Micro-evolution" and "macro-evolution" are outdated terms scientifically. They are rarely if ever used any longer in the literature, since the distinction is technical and too trivial to influence the conclusions drawn from most current research. They have been co-opted by the creationists, and they have been "undefined" so that they have no specific meaning in the creationist context.

Abiogenesis is tangential to evolutionary science, but the researchers in that field may draw from evolutionary explanations to help them construct plausible pathways that may have led to the synthesis of the first primitive life.

 

[Riddermark]

Can any genetic change as considered evolution?

Evolutionists will consider any genetic change to be direct evidence of evolution. In fact, only changes in genetic "frequencies" (gene or rather allele frequencies), are required for evolution--so the biologists say.

In other words, evolution occurs whenever a baby is born (there is a new gene for "whatever" in the population and hence, the frenquency of that gene increase).

Obviously this doesn't capture the essence of what we all think of when we think of evolution, but that apparently doesn't matter. Evolutionary theory is then beyond argument because after all, babies are born all the time.

 

[Jerry Smith]

Obviously this doesn't capture the essence of what we all think of when we think of evolution, but that apparently doesn't matter.

No, it really doesn't matter. Evolution isn't politics. Ultimately, it doesn't matter at all what vague notions the general public hold about it. Many of us would prefer to have a well educated general public, but that is kind of incidental to evolutionary theory.

Evolutionary theory is then beyond argument because after all, babies are born all the time.

Evolutionary theory is only beyond argument so long as it has not been falsified and all of the available data support it. As a theory for explaining the diversity of life on earth, this is still the case.

The fact that we observe gene frequency changes in populations all of the time puts the fact that evolution occurs beyond any doubt.

In much the same way, the evidence for common descent of all life, while it isn't right under the average Joe's nose, is just as compelling to those who are aware of it.

Other interesting conclusions from evolutionary science range from the extraordinarily well supported (like the fact that evolution occurs, or the fact that we share common ancestors with other organisms, etc.) to the very contentious and debatable. So, no - not all of that umbrella term "evolution" is beyond debate, but yes - the parts that Creationists hate are.

In other words, evolution occurs whenever a baby is born (there is a new gene for "whatever" in the population and hence, the frenquency of that gene increase).

Apart from mutations in that baby's gametic germ line, her birth does not introduce new genes into the population. Since she is carrying her parents genes, and all of the new babies do the same, the gene frequencies do not change "every time a baby is born."

However, with sexually reproductive organisms and large populations, it would be difficult for a whole new generation to be born without some gene frequency shift. Scientists are only concerned with this phenomenon from a viewpoint of understanding short-term dynamics.

 

[LewisWildermuth]

Originally posted by Micaiah
How do evolutionists and Christians define and use the term?

evolutionists and Christians???

Like there are no Christians that accept the theory of evolution???

 

[RufusAtticus]

To answer your questions, see my signature.

 

[Screamin-GOD-Till-I-Die]

i have a belly button

 

[sulphur]

Is it an inner or outer

 

[JohnR7]

Originally posted by seebs
As an example, if you gradually heat a petri dish with a culture of bacteria growing in it, you end up with a culture of bacteria which thrive at a higher temperature than the "original" culture did. That's evolution.

Evolution is changing the environmental conditions to provide the peek growing conditions for the bacteria to thrive?

 

[sulphur]

No it is not.This has gone aound many times and yet you still ask the same questions

 

[lucaspa]

Originally posted by Micaiah
What is evolution? How do evolutionists and Christians define and use the term? What about the meaning of abiogenesis and micro and macro evolution? Can any genetic change be considered evolution?

There are creationist and scientific definitions of these terms.  There are not "Christian" and "evolutionist" definitions, since at least half of evolutionary biologists through time (starting with Darwin) were/are Christians.

I'll give you the scientific definitions (and they will not include the "change in gene frequencies over time" since evolutionary biologists specifically reject that definition).

 Appendix and Frequently Asked Questions Science and Creationism, A View from the NAS, the section "What is Evolution?" says:

"Evolution in its broadest sense explains that what we see today is different from what existed in the past.  Galaxies, stars, the solar system, and Earth have changed through time, and so has life on Earth.
"Biological evolution concerns changes in living things during the history of life on Earth.  It explains that living things share common ancestors.  Over time, biological processes such as natural selection give rise to new species.  Darwin called this process "descent with modification," which remains a good definition of biological evolution today."  pg 27

"Thus, evolution, in a broad sense is descent with modification, and often with diversification.  Many kinds of systems are evolutionary ... In all such systems there are populations, or groups, of entities; there is variation in one or more characteristics among the members of the population; there is HEREDITARY SIMILARITY between parent and offspring entities; and over the course of generations there may be changes in the proportions of individuals with different characteristics within populations.  This process consitutes descent with modification.  Populations may become subdivided so that several populations are derived from a COMMON ANCESTRAL POPULATION.  If different changes in the proportions of variant individuals transpire in te several populations,the populations DIVERGE, OR DIVERSIFY. ... All these properties of an evolutionary process pertain to populations of organisms, in which there is hereditary transmission of characteristics (based on genes, composed of DNA or, in a few cases, RNA), variation owing to mutation, and sorting of variation by several kinds of processes. Chief among these sorting processes are CHANCE (random variation in the survival or reproduction of different variants), and natural selection (consistent, nonrandom differences among variants in their rates of survival or reproduction).  It is natural selection that causes adaptation -- improvement in function.  Thus biological (or organic) evolution is change in the properties of populations of organisms , or groups of such populations, over the course of generations. ... Biological evolution may be slight or substantial; it embraces everything from slight changes in the proportions of different forms of a gene within a population, such as the alleles that determine the different human blood types, to the alterations that led from the earliest organisms to dinosaurs, bees, snapdragons, and humans."  Douglas Futuyma, Evolutionary Biology, (1999) pg 4.

Microevolution is "changes within populations and species". 
Macroevolution is "the origin and diversification of higher taxa".
"Many biologists consider the study of species and speciation to constitute the bridge between microevolution and macroevolution."  Douglas Futuyma, Evolutionary Biology, pg 447, 1998

"But we must ask, what exactly are these genera, families, orders, and so on?  It was clear to Darwin, and it should be obvious to all today, that they are simply ever larger categories used to give names to ever larger clusters of related species.  That's all these clusters, these higher taxa, really are: simply clusters of related species.

Thus, in priniciple the evolution of a family should be no different in its basic nature, and should involve no different processes, from the evolution of a genus, since a family is nothing more than a collection of related genera.  And genera are just collections of related species.  The triumph of evolutionary biology in the 1930s and 1940s was the conclusion that the same principles of adaptive divergence just described -- primarily the processes of mutation and natural selection -- going on within species, accumulate to produce the differences we see between closely related species -- i.e., within genera. Q.E.D.: If adaptive modification within species explains the evolutionary differences between species within a genus, logically it must explain all the evolutionary change we see between families, orders, classes, phyla, and the kingdoms of life.  Niles Eldredge, The Triumph of Evolution and the Failure of Creationism. pgs 76-77.

 

[lucaspa]

Originally posted by Riddermark
Evolutionists will consider any genetic change to be direct evidence of evolution. In fact, only changes in genetic "frequencies" (gene or rather allele frequencies), are required for evolution--so the biologists say.

That's definitely not what the evolutionary biologists say.  That reductionist definition leaves out all of reproductive isolation. It also doesn't account for the formation of design in biological organisms.   It also means that genetic drift is evolution, which no one considers that it is. 

Where this comes from is a principle called the Hardy-Weinberg rule.  This derives from Mendelian genetics and says, basically, in a population above the minimum size, that unless outside forces act on the population then the gene frequencies in the population remain constant.

You can see that you can use this immediately to objectively measure natural selection.  However, natural selection, by itself, is not evolution. It is the evolutionary mechanism for getting design, but it is not all of evolution.

Mayr has this acid comment on the reductionist definition:

" 'Evolution' implies change with continuity, usually with a directional component.  Biological evolution is best defined as change in the diversity and adaptation of populations of organisms." pg. 47

"No Darwinian I know questions the fact that the processes of organic evolution are consistent with the laws of the physical sciences, but it makes no sense to say that biological evolution has been "reduced" to physical laws.  Biological evolution is the result of specific processes that impinge on specific systems, the explanation of which is meaningful only at the level of complexity of those processes and those systems.  And the classical theory of evolution has not been reduced to a "molecular theory of evolution," an assertion based on such reductionist definitions of evolution as "a change in gene frequencies in natural populations."  This reductionist definition omits the crucial aspects of evolution: changes in diversity and adaptation. (Once I gave a lump of sugar to a racoon in a zoo.  He ran with it to his water basin and washed it vigorously until there was nothing left of it.  No complex system should be taken apart to the extent that nothing of significance is left.)"  Ernst Mayr, Evolution, Scientific American 239: 47-55, Sept. 1978. 

 

[ikester7579]

Which evolved first, man or woman? Which has a more complicated body and would require more mutations and take longer to evolve? Which organ of the body evolve first and how did it survive by itself until the other organs evolved? Only a sudden creation of man and woman can explain this. Don't believe me? Try taking one of your organs out and see how long you live with out it. The body has to many vital organs that rely on one another to survive. For if it were so easy then I might believe in evolution. But creating or evolving life is not easy, for if it were science would have already been able to create it from nothing. Why is not evolution still going on? All of the ingredients are still here. I guess some questions can't be answered.

 

[sulphur]

I have my appendics ,lymph nodes and spleen removed. Whats the difference

 

[ikester7579]

Try to take your heart out, remove you blood, your lungs, pancrease, your brain which controls everything, your digestive system, nervous system, all your bones etc... You are still here because you have them right? So which one of these evloved first and how did it survive until the rest mutated into being?

Also the cells that make up these organs are different. How long did it take for all these cells to mutate into being and from that point mutate the organ? It is said that the eye took 30,000 mutations to come into being. How many mutation did it take for the brain? And sense the brain is the most complicated organ in the body and would take the longest to mutate into being, this would mean the first humans had no brain. It had not mutated into being yet. Just a guess, but I believe the brain would take close to 1,000,000 times longer to mutate into being. Maybe someone correct me on this.

 

[ikester7579]

To many organs to little time.

 

[sulphur]

Are you a doctor? If not, you would realise you are talking absolute rubbish if you did a little readingyou would realse so many organs can be trans planted