Evolution: WHAT IS IT?
Let's unpack: WHAT IS EVOLUTION?!
It is often stated that evolution is the base of all biological knowledge. It involves the demonstration or explaining of how life on Earth has adapted and changed over a tremendous period of time, though more specifically - millions of years.
In this blog, we will be diving into what evolution really is, why it is important to understand, and tackle the common misconceptions of evolution - and how to respond to them.
So, first of all, what is evolution exactly?
Evolution is the process of showing how species of organisms - not limited to humans - change over time through aspects like natural selection, mutation, genetic drift, gene flow, and nonrandom mating. Every living thing has DNA/genetic components that determine traits - size, eye color, maybe behavior, and so on. Over many, and I mean many generations, small changes occur and these unique traits ultimately compile together to lead to the emergence of new species. This does not just happen overnight.
This also might be a good time to mention: micro and macroevolution. Microevolution is a small, gradual change of a population through time from generation to generation. For example, the evolution of pesticide-resistant mosquitoes or Darwin's finches. Macroevolution is the process that gives rise to the new species and higher taxonomic groups with widely divergent characteristics, so larger changes. For example, the evolution of whales from land mammals.
It is important to remember that traits that enhance or optimize survival and reproduction are passed on to the next generation (from parents), thus leading to the slow but sure development of new species (Stanford, 2020). This is a demonstration of the mechanism that explains how organisms' adaptations to their environment impact their likeliness to survive and eventually reproduce; otherwise known as natural selection. Keep in mind, though - natural selection is a component factor in evolution, though it is not the origin of it. Evolution addresses all practices that drive changes in species over generations (mutation, genetic drift, etc.) (Stanford, 2020). We will debrief later on about evidence for evolution, including genetic similarities, fossils, and more components of proof.
Continuing the discussion on natural selection, the concept was initially established by Charles Darwin and Alfred Russell Wallace. They observed species that were similar but had distinct differences, and noticed comparable patterns in organisms. Although they independently conceived a mechanism to explain how and why such changes could take place, Darwin ultimately crafted the mechanism that is now known as natural selection, where organisms that are better adapted to their environment tend to survive and produce more offspring. Further, more offspring are produced than can survive. Offspring vary among each other regarding their characteristics and those variations are inherited. It is also important to mention - natural selection can only take place if there is variation, or differences, among individuals in a population. The lead to evolution comes from the more favorable traits from organisms becoming more common in populations of species over time.
Darwin is seen on the left, and Wallace on the right.
It is also important to be familiar with the definitions of the other basic causes of evolution. We have already discussed natural selection, next is mutation. Mutation is a change in the DNA sequence of an organism's genome, which can be seen through reduced fitness (likeliness to survive/reproduce), may produce a phenotype with a beneficial effect on fitness, or, may have no effect on fitness at all. Next, genetic drift is the variation in the relative frequency of different genotypes in a population, mainly affecting small populations. Further, gene flow is the flow of alleles in and out of a population resulting from the migration of individuals or gametes. Finally, nonrandom mating refers to the mechanism where organisms in a population do not mate sporadically or unintentionally; they specifically choose partners based on definitive traits or characteristics. This could potentially trigger alterations or changes in allele frequencies in a population and affect evolutionary changes or processes.
The two different kinds of evolution are divergent and convergent evolution.
Divergent evolution is when two species evolve in different directions from a common point, resulting in homologous structures - where there are shared similarities within organisms because of a common ancestor (UC Museum, 2020). A famous example of this would be Darwin's finches or mammalian limbs.
Convergent evolution is when similar structures arise through evolution independently in different species, and results in analogous structures - where organisms are similar in function and appearance, but do not share an origin in a common ancestor (UC Museum, 2020). For example, sharks and dolphins. Sharks are fish, and dolphins are mammals.
Why does evolution even matter?
Understanding evolution is imperative because it assists us in grasping and interpreting the DIVERSITY and UNIQUENESS of life on Earth across a multiplicity of species, organisms, and furthermore. To add, evolution gives us the answer as to why organisms are so fitted and adapted in their environments, and how they alter in terms of challenges in their surroundings, such as climate variability, illnesses, and so on (UC Museum, 2020).
If you are not already convinced that we all need to be educated on evolution, there are very reasonable applications of evolution in fields such as agricultural (development), the business world, and even human resources. For example, companies may use evolutionary concepts to accommodate and adapt to marketing modifications and development, showing the significance of variation and evolutionary progression. Evolution is persistently and continuously sculpting, or structuring, the world around us as we speak.
Now, for the Common Misconceptions About Evolution:
Misconception One: "Evolution is just a theory."
In science, a theory is not simply a "guess." It is a well-supported explanation backed by evidence, and, in this case, years of research. For example, evidence of evolution can be seen through the existence of fossils, observed change in species over time, and the gathering of genetic data (Pope, 2021).
Misconception Two: "Individuals evolve."
Populations evolve, not individuals. In other words, evolution occurs at the population level spanning across many generations - it does not occur within a single person's lifetime. For example, as stated in class, a giraffe does not simply stretch their neck as far as they possibly can to reach their food, then immediately pass that trait to their offspring. Rather, long necks became more apparent over generations within populations as those with longer necks (naturally) were, and still are, more likely to survive and reproduce.
Misconception Three: "Evolution explains the origin of life."
Evolution does not demonstrate how life began, rather, it conveys how life changes over periods of time. Further, evolution only deals with how organisms are diverse (and why), and how they adapt once their life has already began. The origin of life is a completely different scientific analysis.
Misconception Four: "Organisms evolve on purpose."
Evolution is not a process of intent. Organisms do not choose to evolve, rather, mutations in DNA create new traits. If those traits are able to improve or benefit survival/reproduction, they may become more commonly seen through natural selection.
Misconception Five: "Evolution is controversial among scientists."
There is an intense majority of scientists who accept evolution as the best demonstration and justification for the uniqueness and diversity of life on Earth. The controversy that does exist, however, is about the specifics of how evolution happens, not whether it does happen.
Misconception Six: "Other theories should be taught."
No alternative scientific theories hold the same level of evidence as evolution.
So, what was your point again? Can we wrap this up?
Evolution is the process that explains the mechanisms of how populations of organisms change over time. It provides the ultimate explanation for the astounding diversity of life on Earth. Often misunderstood, the evidence supporting evolution has made it imperative to scientists and to the general public alike in understanding evolutionary progression and development, and how we can address things like disease, climate change, and other modern challenges (Pope, 2021). Remember, evolution is not "just a theory." Rather, it is an established principle backed by decades of research, without which understanding of complex life on our planet would not have been possible.
References
Stanford Encyclopedia of Philosophy (2020). Evolution.
https://plato.stanford.edu/entries/evolution/
https://plato.stanford.edu/entries/evolution/
University of California Museum of Paleontology. (2020). An
introduction to evolution.
Pope, D. (2021). The role of evolution in human affairs. In The
evolution of everything: How new ideas emerge (pp. 1-20).
Princeton University Press.
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