What is the difference between micro- and macroevolution? Can the same processes that produce small changes within a species produce entirely new species?
Charles Darwin’s theory of evolution promotes the idea that a process analogous to artificial breeding also occurs in nature; he called that process natural selection. Darwin also believed that changes that he observed in existing species due primarily to natural selection could, if given enough time, have produced all the different species he saw around the world.
But is microevolution (small changes within a species) really a step toward macroevolution (major changes producing new species)—or is it something else entirely?
Beginning in the 1930s, the term microevolution was used by some to describe changes within existing species.
“Microevolution refers to varieties within a given type. Change happens within a group, but the descendant is clearly of the same type as the ancestor. This might better be called variation, or adaptation, but the changes are ‘horizontal’ in effect, not ‘vertical.’ Such changes might be accomplished by ‘natural selection,’ in which a trait within the present variety is selected as the best for a given set of conditions, or accomplished by ‘artificial selection,’ such as when dog breeders produce a new breed of dog.
“The small or microevolutionary changes occur by recombining existing genetic material within the group. As Gregor Mendel observed with his breeding studies on peas in the mid 1800’s, there are natural limits to genetic change. A population of organisms can vary only so much” (John D. Morris, Ph.D., “What Is the Difference Between Macroevolution and Microevolution?”).
The variation and adaptation sometimes referred to as microevolution does not conflict with the biblical account of creation. God created that variety into all the life we see on earth—all the kinds of plants and animals He created.
The meaning of “kind” in the Bible
The Bible uses the word kind in a special way in the creation account.
“Then God said, ‘Let the earth bring forth grass, the herb that yields seed, and the fruit tree that yields fruit according to its kind, whose seed is in itself, on the earth’; and it was so” (Genesis 1:11).
God also created the sea creatures and the birds “according to their kind” and the land animals “each according to its kind” (Genesis 1:21-24).
The key concept in these scriptures is that each kind reproduces after its own kind. The offspring are similar to their parents. They are also fertile and can only mate with others of the same kind, producing offspring that look similar to their ancestors.
Plants, trees, fish, birds, reptiles, insects and mammals reproduce consistently after their own kind. Apple trees don’t produce oranges, and cattle don’t produce sheep. Inherent within the genes of these kinds is a variety that will come out in successive generations as demonstrated by dog breeding and varieties within other animals, plants, birds and fish.
Biblical kinds compared to species
Evolutionary biologists use several definitions for a species, including the morphological species concept (classified based on physical features) and the genetic species concept (defined as clusters of genetically similar organisms).
Another definition of a species—biological species concept—would correspond most closely to the biblical definition of a kind:
“Most broadly, a species is a group of organisms with a shared, closed gene pool. According to this definition, a species is made up of all the organisms that are able to mate with each other and produce fertile offspring. For example, lions produce offspring with other lions, and tigers with other tigers. However, if lions and tigers are brought together in captivity they can occasionally produce a hybrid called a liger or tigon, but these hybrids are not themselves able to reproduce. Without being able to produce fertile offspring, it then follows that lions and tigers are separate species. Another term used for the inability to interbreed is reproductive isolation” (“Biological Species Concept”).
Microevolution is observed in nature and in artificial breeding and is noncontroversial. It is the variation we see due to the variety in the genes of the parent organisms—all within the same species or biblical kind.
Macroevolution, however, is controversial and is at the heart of the debate between evolutionists and creationists.
Let’s take a closer look at what macroevolution means.
“Macroevolution refers to major evolutionary changes over time, the origin of new types of organisms from previously existing, but different, ancestral types. Examples of this would be fish descending from an invertebrate animal, or whales descending from a land mammal. The evolutionary concept demands these bizarre changes. …
“Evolutionists assume that the small, horizontal microevolutionary changes (which are observed) lead to large, vertical macroevolutionary changes (which are never observed). This philosophical leap of faith lies at the eve of evolution thinking” (“What Is the Difference Between Macroevolution and Microevolution?”).
In the 1930s neo-Darwinists proposed that genetic mutations could help explain how macroevolution could occur. The reason microevolution does not lead to macroevolution is that microevolution only involves variations based upon existing genes. No new genetic information is being added. In macroevolution, however, new genetic information would have to be added to an organism and then this must be passed down through the genes to its descendants. This information would have to accumulate over many generations to produce macroevolution.
The reason microevolution does not lead to macroevolution is that microevolution only involves variations based upon existing genes. No new genetic information is being added.The new genetic information must be information that the life-form did not originally possess. New genetic information is similar to new blueprints.
Evolutionists trying to prove that new genetic information can be added through mutations will sometimes use the example of humans who possess an extra chromosome at position 21. This is a harmful mutation resulting in Down syndrome. This is not new information, however. The human genome already had the information; it was just duplicated.
What about other mutations? Almost all mutations are bad for the organism, and even the few that have positive effects can also cause problems.
A gene known as HbS is a point mutation familiar to many. It affects the function of hemoglobin, which helps carry oxygen in our blood. Having one normal copy of the gene and one mutated copy confers resistance to malaria. But having two copies of this mutation causes sickle-cell anemia; and without good medical care, it can cause death at an early age (PBS.org).
There is also a mutation that helps protect against HIV involving a cell surface protein called CCR5. It, however, puts those individuals with the mutation more at risk for the West Nile Virus (“Mutation That Protects Against HIV Infection May Raise Risk of West Nile Virus Illness”).
The net effect is that these seemingly beneficial mutations also put an individual more at risk for another disease. This means they are hardly mutations that would demonstrate macroevolution. As well, these mutations only use existing genes, not new genetic information.
Many evolutionists say the reason we don’t see macroevolution is that mutations are rare, and the length of human generations makes it hard to study how genes may change over time. This challenge is lessened by studying mutations in bacteria, because bacteria reproduce very quickly. Richard Lenski has been growing E. coli bacteria since 1988 and, as of April 2014, has witnessed 60,000 generations.
The E. coli bacteria were given glucose to eat; but the researchers also provided citrate, since they wanted to see if the E. coli could mutate to use it as a food source in an oxygen-rich environment. After 31,500 generations, a strain of E. coli was produced that was able to use citric acid as a carbon source in an aerobic environment. This mutation in E. coli was the result of a copy of a gene being moved to a new location. The E. coli had changed the rules for how it used existing genes.
Another way of looking at this experiment is that after 60,000 generations of E. coli bacteria, the bacteria are still E. coli bacteria. The bacteria have not evolved into another organism. (For more information about gene mutations, see the Life, Hope & Truth article “Science and the Bible: Do You Have to Choose One or the Other?”)
Do the Galápagos finches prove macroevolution?
Charles Darwin was a naturalist aboard the British survey ship HMS Beagle. In 1835 the Beagle visited the Galápagos Islands, about 600 miles off the west coast of Ecuador. There were 13 species of finches scattered among the almost two dozen islands. The finches differed mainly in the size and shape of their beaks.
Darwin does not mention the finches in his diary of the Beagle voyage except in passing reference, and they are never mentioned in The Origin of Species. According to historian of science Frank Sulloway, Darwin “possessed only a limited and largely erroneous conception of both the feeding habits and the geographical distribution of these birds.” And as for the claim that the Galápagos finches impressed Darwin as evidence for evolution, Sulloway wrote, “nothing could be further from the truth” (quoted by Jonathan Wells, Icons of Evolution, 2000, p. 161).
Two scholars, Drs. Peter and Rosemary Grant, went to the Galápagos Islands in 1973 to try to observe evolution in action by studying the finches. They finally focused on Daphne Major, a very small island in the Galápagos. The story of the Grants’ research was recorded in Jonathan Weiner’s 1994 book The Beak of the Finch.
The Grants conducted a very detailed and accurate study of the finches. Up until 1976, rainfall was average. Then came the drought of 1977, when only one inch of rainfall fell. This caused a severe reduction in the number of seeds on the island. The population of medium ground finches was reduced to 15 percent of normal. The survivors of this drought tended to have larger bodies and larger beaks. They were more capable of cracking the tough, larger seeds that remained.
In 1982-1983 an El Niño weather pattern brought heavy rains to the Galápagos Islands. Over 10 times more rain fell than normal and 50 times more than during the drought. Average beak size in medium ground finches returned to the previous value.
“So the evolutionary change that the Grants and their colleagues had observed during the drought of 1977 was reversed by the heavy rains of 1983. ‘Selection had flipped,’ wrote Weiner. ‘The birds took a giant step backward, after their giant step forward.’ As Peter Grant wrote in 1991, ‘the population, subjected to natural selection, is oscillating back and forth’ with every shift in climate” (Wells, pp. 167-169).
Oscillating changes cannot produce any long-term changes. There was no upward trend in beak size. The beak sizes tended to oscillate from small to large and back. The study of the Galápagos finches is not evidence of macroevolution at all. It is a good example of microevolution or variation.
God is the creator of all life
Evolutionists consider macroevolution to be an extension of microevolution. Macroevolution, however, requires new genetic information to produce an entirely new type of animal—and that has never been observed.
God is the creator of the earth and universe. He created all the life we see on this earth. All the kinds that God created contained genes that allowed for a certain amount of variety in their descendants to fit different environments, but He also put limits on the variation of all the kinds of creatures we see on the earth. We see this in the words He used when creating these animals—that they would reproduce “according to their kind.” This would be described as microevolution, not macroevolution.