When it comes to the topic of evolution, you might have heard creationists say that “microevolution” happens, but “macroevolution” is just a myth – since this is how many people constantly hear these two terms from creationists, they think they are made up, which is not the case.
What is Microevolution?
Microevolution refers to small, incremental changes that occur within a species over time. These changes happen at the genetic level, affecting traits such as color, size, or resistance to diseases. Microevolution is the process by which populations adapt to their environments and is observable within a relatively short period, sometimes even within a human lifetime.
Examples of Microevolution
One of the most well-known examples of microevolution is the development of antibiotic resistance in bacteria. When bacteria are exposed to an antibiotic, most of them die. However, some may have mutations that make them resistant to the drug, thanks to which these bacteria survive and reproduce, passing on their resistant genes to their offspring. Over time, the population of bacteria becomes more resistant to the antibiotic.
Peppered moth is another example of microevolution. During the Industrial Revolution in England, the peppered moth (also known as Biston betularia) underwent a significant change in color. Before the revolution, most peppered moths were light-colored, which helped them blend in with the lichen-covered trees. However, as industrial pollution darkened the trees with soot, the darker-colored moths had a survival advantage because they were less visible to predators. Over time, the population of peppered moths shifted from predominantly light-colored to predominantly dark-colored—a clear example of microevolution in response to environmental changes.
One final example is from Darwin’s Finches. On the Galápagos Islands, Charles Darwin observed finches with different beak shapes and sizes, adapted to their specific diets. Over generations, these finches evolved beaks suited to the types of food available on their respective islands. This is another instance of microevolution, where small genetic changes accumulate over time to produce a diversity of beak shapes in the finch population.
What is Macroevolution?
While microevolution refers to small changes within a species, macroevolution refers to larger-scale changes that can result in the formation of new species. Macroevolution occurs over much longer periods, often millions of years, and encompasses the broader patterns of evolutionary change, such as the emergence of new species, the extinction of others, and the evolution of complex structures like wings or eyes.
Examples of Macroevolution
As you know Whales are descended from land-dwelling mammals that lived about 50 million years ago. Over millions of years, these early ancestors of whales underwent significant changes: their limbs transformed into flippers, their bodies became more streamlined for swimming, and they developed the ability to hold their breath for extended periods underwater. These large-scale changes are examples of macroevolution, illustrating how a land mammal gradually evolved into the modern whale.
Birds, on the other hand, are believed to have evolved from small theropod dinosaurs around 150 million years ago during the Jurassic period, which involved a series of macroevolutionary changes, such as the development of feathers, the modification of forelimbs into wings, and the changes in skeletal structure that allowed for flight. The fossil record shows a progression of species with increasingly bird-like characteristics, demonstrating the gradual nature of this macroevolutionary process.
Last, humans share a common ancestor with the great apes, and our evolutionary history is marked by significant macroevolutionary changes. These include the development of bipedalism (walking on two legs), the enlargement of the brain, and the use of tools. Over millions of years, these changes led to the emergence of Homo sapiens, our species, which is distinctly different from our ape-like ancestors.
What Ties Microevolution & Macroevolution
One common misconception is that microevolution and macroevolution are entirely separate processes. In reality, macroevolution is essentially microevolution writ large—it’s the accumulation of small, microevolutionary changes over a long period that leads to the large-scale patterns we observe in macroevolution.
For instance, if a population of animals is divided by a physical barrier, like a mountain range or a river, the two groups may experience different environmental pressures. Over time, microevolutionary changes—such as differences in coloration, size, or behavior—accumulate in each group. If these differences become significant enough, the two groups may no longer be able to interbreed, resulting in the emergence of two distinct species. This process, known as speciation, is a macroevolutionary event that arises from many microevolutionary changes.
Accepting Microevolution But Reject Macroevoluton Is Senseless
Accepting microevolution while rejecting macroevolution is like acknowledging that a child grows a little taller every day but refusing to believe that the child will eventually become an adult. Just as small, daily changes accumulate to transform a baby into a fully grown person, the small genetic changes that occur in microevolution accumulate over time to produce the large-scale changes we see in macroevolution.
At the end of the day, microevolution and macroevolution are not separate phenomena; they are part of the same continuous process. Just as it would be nonsensical to think that a person could age one year at a time without eventually becoming older, it is equally senseless to accept the idea that small evolutionary changes do occur, but they never accumulate.
#Evolution, #ScienceFacts, #Biology
