What is the difference between Microevolution and Macroevolution?
Question: "What is the difference between Microevolution and Macroevolution?"
Answer: Microevolution is an uncontroversial, well-documented, naturally occurring biological phenomenon. It happens every day. It is the process whereby preexisting genetic information is rearranged, corrupted, and/or lost through sexual reproduction and/or genetic mutation producing relatively small-scale (“micro”) changes within a population. Two long-haired dogs producing a short-haired puppy would be an example of microevolution (we’ll look at why in a moment).
Macroevolution is the somewhat more controversial, theoretical extrapolation of microevolution that requires the introduction of new genetic information. It is believed to produce large-scale (“macro”) changes. An amphibian evolving into a reptile or a reptile evolving into a bird would be examples of macroevolution.
Macroevolution is an important concept because Darwinists believe that it is the mechanism for their idea that all life evolved from a common primordial ancestor. Since microevolution is small-scale (“micro”) biological change, and macroevolution is large-scale (“macro”) biological change, many Darwinists argue that macroevolution is simply the accumulation of microevolutionary changes over time. Ostensibly, this is a reasonable extrapolation of microevolution. Darwinists, therefore, often cite evidence for microevolution as evidence for macroevolution. However, because macroevolution requires new additional genetic information, no amount of rearrangement, corruption or loss of existing genetic information will produce macroevolution. In other words, no amount of microevolution will produce macroevolution. Darwinists draw a false correlation between the two. We will now take a closer look at both microevolution and macroevolution.
We will begin with microevolution. Let’s say, for example, that within the dog genome there are both a gene for long hair (H) and a gene for short hair (h). Now imagine that the very first dogs possessed both genes (Hh). If two Hh dogs bred, half of the Hh from one dog would combine with half of the Hh from the other dog through sexual reproduction, and there would be four possible outcomes for offspring: HH, Hh, hH and hh puppies.
Now let’s suppose that the longhair H gene is the dominant gene and the shorthair h gene is the recessive gene. That means that when a dog possesses both genes, only the longhair H gene will be expressed, i.e., the dog will have long hair. So, if two longhair Hh dogs bred, the odds are that they would have three longhair puppies (HH, Hh and hH) and one shorthair puppy (hh). The two longhair dogs having a shorthair puppy would be an example of change within a population resulting from the rearrangement of preexisting genetic information (i.e., microevolution).
If a longhair Hh dog bred with a shorthair hh dog, the odds are that they would have two longhair puppies (Hh and hH) and two shorthair puppies (hh and hh). If two shorthair hh dogs bred, they would produce only shorthair hh puppies. And if this group of shorthair hh dogs became isolated from the longhair HH, Hh and hH dogs, they would lose access to the longhair H gene altogether and become an “isolated gene pool.” When it comes to dogs, isolated gene pools are called “purebreds.” Likewise, if a group of longhair HH dogs became isolated from the shorthair h gene, they would be considered purebred. On the other hand, the longhair Hh and hH dogs would be called “mutts.” Human breeders have been exploiting this biological phenomenon for thousands of years, selecting dog couples to mate based on their appearance in order to accentuate and attenuate traits gradually over time and thereby introduce new breeds.
Now imagine that, within a longhair Hh population, a genetic mutation disabled the expression of the longhair H gene, and that mutation was reproduced over and over again within the population. The formerly longhair population would become shorthair, not because of the rearrangement of genes through sexual reproduction but because of genetic mutation.
Another important example of microevolution through genetic mutation is when a population of insects becomes resistant to a certain pesticide, or when bacteria become resistant to antibiotics. What happens in these instances is that through mutation the insects or bacteria lose the ability to produce the enzyme which interacts with the poison. The pesticide or antibiotic, therefore, has no effect. But the insects or bacteria don’t gain any new genetic information; they lose it. It is not, therefore, an example of macroevolution as it is often misinterpreted, but of microevolution. As biophysicist Dr. Lee Spetner explains, “All of the mutations that have been examined on a molecular level show that the organism has lost information and not gained it.” (“From a Frog to a Prince,” documentary by Keziah Films, 1998)
Now let’s look at macroevolution. Darwinists believe that all life is genetically related and has descended from a common ancestor. The first birds and the first mammals are believed to have evolved from a reptile; the first reptile is believed to have evolved from an amphibian; the first amphibian is believed to have evolved from a fish; the first fish is believed to have evolved from a lower form of life, and so on, until we go all the way back to the first single-celled organism, which is believed to have evolved from inorganic matter. [The acronym to remember is FARM: Fish to Amphibian to Reptile to Mammal.]
The very first single-celled organism did not possess all of the genetic information for a human, so in order for humans to have ultimately evolved from a primitive single-celled organism, a lot of genetic information had to be added along the way. Change resulting from the introduction of new genetic information is “macroevolution.”
The reason why macroevolution is controversial and remains theoretical is that there is no known way for entirely new genetic information to be added to a genome. Darwinists have been hoping that genetic mutation would provide a mechanism, but so far that has not been the case. As Dr. Spetner again explains, “I really do not believe that the neo-Darwinian model can account for large-scale evolution [i.e., macroevolution]. What they really can’t account for is the buildup of information. …And not only is it improbable on the mathematical level, that is, theoretically, but experimentally one has not found a single mutation that one can point at that actually adds information. In fact, every beneficial mutation that I have seen reduces the information, it loses information.” (Ibid.)
Creation vs. Evolution
When Creationists say they don’t believe in evolution, they are not talking about microevolution. They are referring to macroevolution. Microevolution is a credibly observed scientific phenomenon. What Creationists do not believe in is Darwin’s macroevolutionary extrapolation of microevolution. Unlike microevolution, there is no true scientific evidence for macroevolution, and, in fact, there is significant evidence against it. The distinction between microevolution and macroevolution is, therefore, an important one for those interested in the creation-vs.-evolution debate.
Recommended Resources: Darwin's Doubt: The Explosive Origin of Animal Life and the Case for Intelligent Design by Stephen Meyer and Logos Bible Software.
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Questions about Creation
What is the difference between Microevolution and Macroevolution?