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what is the difference between natural selection and evolution?

8 Answers

  • 1 decade ago
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    Evolution is the process we see. Natural selection is the mechanism that explains it.

    Basically, evolution just means "slow change." We often refer to the evolution of galaxies, or languages, or political systems.

    Biological evolution is the slow change of a species over time. That's all. (Important ... it is the change in a *species* not an individual.) Evolution is a concept that has been around since the Greeks. But what was missing was a *mechanism* that explained what drives that change. I.e. it is apparent that species *change* (evolve) over time, but why? And how?

    Natural selection is the *mechanism* ... the 'why' and the 'how'. It is an explanation for what causes the slow change in a species in response to environment. This was Darwin's contribution (contrary to misinformation promoted by Creationists, Darwin did not "invent" evolution ... he just explained it.)

    To explain how things evolve, natural selection just starts with three facts that are trivially observable:

    1. Variation - Individuals in a species are not all identical.

    2. Inheritance - Individuals pass on traits to their offspring.

    3. Competition - More individuals are born than can possibly survive/reproduce.

    Given these three things, natural selection just says that those individuals that have traits that give them some advantage in surviving/reproducing, will pass those traits on to their offspring. And in this way those traits will propagate (spread) into the population.

    And that is how (and why) a species will evolve (change) over time.

    That's it.

    I could stop there, but to address the so-called "controversy" (which is not considered much of a controversy among scientists):

    Almost everybody (even Creationists) agree that evolution occurs ... i.e. things change over time. (This is what Creationists call "microevolution.")

    Where they disagree is in whether evolution through natural selection can explain how new species are born. (What scientists call "speciation" and Creationists call "macroevolution.")

    Most scientists agree the answer is Yes ... evolution can cause speciation. All it needs is TIME. In other words, the only difference between "micro-" and "macro-evolution" is the time scale involved. That's why scientists call them both "evolution."

    Here's an example of how it works: If two subpopulations of a species get isolated from each other (a river, a mountain, a lake drying into two lakes, migration, etc.) then the two subpopulations will evolve (change) in different directions ... because they are not influencing each other genetically. If this isolation is long enough, then through the accumulation of new traits, the two subspecies will first lose the desire, and eventually the ability, to interbreed with each other. Even if they were to become no longer isolated geographically, they are forever isolated *genetically*. So what was one species has now branched into two species. And the two species are now free to continue evolving in completely different directions.

    And that is one way that speciation occurs through evolution ... as explained by natural selection.

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  • 1 decade ago

    Natural Selection is a process by which genetic traits which give an individual an increased chance of survival are passed on to that individual's children. For example, take group of rabbits, all the same species. Let's say half of them are genetically predisposed to building up a layer of insulating fat. In the current climate, this genetic trait gives neither an advantage, nor disadvantage, so it's spread roughly evenly throughout the population. Now say that the climate shifts, and it is suddenly much colder. Suddenly, the rabbits without the fat are freezing to death, and are unable to provide well for their children. However, the rabbits with a layer of fat will flourish just as well, and so will have more food and more children than the skinny rabbits. Within a few generations, most, if not all of the skinny rabbits will be dead, and only the rabbits who were predisposed to having fat will have survived. They will have been naturally selected.

    Evolution takes this theory one step further. Evolution states that after several generations, the fat rabbits will pick up other traits, as more and more environmental challenges naturally select more and more specialized versions of the rabbits. Combined with random mutation, eventually it will become impossible for these rabbits to interbreed with other populations of rabbits around the world. Eventually, they will no longer be "rabbits" but will actually become their own distinct species.

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  • 1 decade ago

    Evolution is a change in a gene pool over time. This is a proven fact from experimentation and observation. Natural selection is a theory as to what causes evolution.

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  • Anonymous
    1 decade ago

    based on my understand (which may not be the greatest) natural selection is how "bad" genes go extinct and good genes thrive, and evolution suggests that genes mutate through generations

    example, if there were a gene that made someone very ill or mentally retarded, they are less likely to survive to reproduce (assuming it is a natural society, like animals) and thus their genes won't get passed on, so the gene will go "extinct", this works even for genes that only give a slight advantage to some, because if the difference of chance in survival to reproduce is even .000001%, after thousands of generations the stronger gene will become more common

    natural selection is quite obvious and thus not debated like evolution

    and as i said earlier, im no bio expert or anything, so dont blame me if im wrong :D

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  • 1 decade ago

    EVOLUTION is a constant process by means of which populations of living beings (ALL populations of ALL living beings) change over time; this change happens because at least part of the variations present in any population are encoded in the genetic material (DNA) and are passed onto the next generation, that is, these traits are heritable.

    In terms of population genetics, evolution is the change of allelic frequencies in time.

    NATURAL SELECTION is one of the "forces of evolution", or mechanisms through which evolution occurs.

    Charles Darwin was the first one to describe this mechanism clearly; it is the differential survival and reproduction of individuals according to the possesion of certain character states that are more or less "fit" for a given environment. By means of natural selection, the individuals that possess these character states (for instance, in a population of blackbirds, those with longer beak, or wingspan within certain limits, or those that prefer certain times of the day to feed, etc) will survive and be able to procreate more successfully than others, thus producing more offspring, thus spreading their alleles (=versions of genes) in the next generation of the population. If this happens, the allele frequencies of the population will change, and as I wrote above, that's the definition of evolution.

    The process of natural selection creates what we perceive as ADAPTATIONS, because it hones advantageous characteristics into being more advantageous if it's possible, and becoming specializations. However, any adaptation is not an inherent characteristic of the living being, i.e. it can only be understood in its environmental context. And not all the traits of a living being are adaptations, because there are other factors at work that are as important as natural selection for evolution.

    I hope you can understand the difference. *Evolution* is change in life through time, while *natural selection* is one of the mechanisms of change (these include (1) mutation - the ultimate origin of variation- , (2) migration - genetic flow- , (3) genetic drift - random changes -, in addition to (4) natural selection).

    Many authors also include (5) assortative mating - differential (non-random) choice of reproductive mates-, although this causes a change in genotypic frequencies, rather than in allelic frequencies.

    Here's a great site fom Berkeley:

    Source(s): I'm a biologist.
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  • natural selection and evolution are related. but natural selection for example is like, "the young man picked the prettier and smarter girl over the less prettier and dumber girl to marry" u know what i mean! and when the two of them have kids, they pass on their looks and so on for many generations to come. all of the information from them passed on to their generations and like in this case, in 100 years, people would be prettier and smarter. (evolution) of course there are different examples. so i hope i helped some!

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  • 1 decade ago

    Natural selection is the process by which favorable traits tend to proliferate and deleterious traits tend to fade as generations pass. Evolution includes broader concepts such as colonization (Darwin's finches), mutation (introduction of new variation), and developmental biology.

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  • Anonymous
    1 decade ago

    simply natural selection leads to Evolution.. it's dat those who has selective advantages survive over those who hasnot.. and so genes with favourable alleles are passed among generations.. which leads to evolution..

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