Why Teach Evolution in Biology?

Because It is The Right Thing to Do!

Ask any high school student and you will get the same response: “Biology is just memorization, there is no structure or connection between the topics.”

Biology is Much More than Memorization

We used the largest popular science Twitter account in Turkey, Evrim Ağacı (Tree of Evolution) to pose the following question: “Which of the following high school classes require the most memorization, in the sense that learning one topic helps learning next topics the least and therefore, you feel like all the topics are mostly independent and you cannot get the ‘logic’ of that branch of science?” The options were physics, chemistry, biology, and mathematics. Of the 28,380 responses, the overwhelming majority (56% of the respondents) selected biology. The other options received somewhat evenly distributed responses: physics (12.6%), chemistry (17.9%), mathematics (13.4%).

Twitter (Pixabay)

This response is not surprising. Over the past three decades students we encountered in Turkey have always echoed similar beliefs. We are certain that if the question was asked in other countries the response would be similar. At least in the countries similar to Turkey, where the biology curriculum does not explicitly integrate evolution into the topics. When you avoid mentioning evolution systematically, it is inevitable that the students will eventually develop a distorted understanding of biology, without any solid foundations. That is why they will see blind memorization as the only way to be successful – they will not try to understand and appreciate the interconnectedness of biological sciences. Because teaching biology without evolution is like teaching physics without forces, chemistry without bonds.

Evolution is the Backbone of Biology

Evolution is the backbone of biology. Evolution is the “main theme of evolution”, as one of the most widely taught college biology textbooks, Campbell’s Biology writes. Evolution is the foundation of biology. As Dobzhansky famously said, “Nothing makes sense except in the light of evolution.” But make no mistake: you technically can teach everything in biology without evolution. The problem is: it would make no sense. It would only be a collection of terms, species, features, organs, systems and concepts that have no relation to one another whatsoever.

Honey Bee Pollinating Lavender
Honey Bee Pollinating Lavender (Pixabay)

For example, in biology, every student learns a concept called “mutualism”. This is simply the reciprocal benefit species get from their ecological interactions with one another. For instance, various plants produce nectar and honeybees collect this nectar for food and honey production. While trying to collect the nectar, pollens (sperms) of the plant will also stick to the bee and as the bee travels from plant to plant, searching for more nectar, it will transmit these pollens as well, allowing plants to reproduce much more efficiently than, say, the random chance of wind being the carrier of pollens. So, both the plant and the bee benefits from such relationship, it is pretty cool!

Now, you can teach mutualism without evolution (like we did in the above paragraph) and it has been done, at least in Turkey, for decades now. But how will you answer when students start asking some important questions: Why did such a mutualistic relationship between species arise in the first place? Why do some other species (or all other species for that matter) do not have mutualism, if it is so beneficial to each party? How do we measure the level of advantage mutualism gives to species when compared to other evolutionary pollen/seed dispersal strategies, such as lawn burweed seeds (famously known as “stickers”) or other ways pollen travels? What processes have led to such mutualism? These questions cannot be answered satisfactorily without talking about evolutionary biology and concepts such as co-evolution. The way the natural world works will never “click” in the minds of students; therefore, they will just memorize, pass some tests, and move on.

Sea Sponges
Sea Sponges (Pixabay)

Evolution is the Basis of Biology and Explains Life

Similarly, you can talk about all the organs and systems in biology without evolution. You can talk about how there are no real nervous system in sponges, which are actually a phylum of animals, and how simple the “nerve net” nervous system of hydras are, how flatworms have a slightly more complex nervous system with some ganglia (“brain-like nerve nodes”) forming for the first time, and finally, how we start seeing real brains in some other invertebrates and much more complex brains in vertebrates. Then you can switch to the excretory system, cardiovascular system, or digestive system. You can investigate all these species (and taxa) again and you will almost always have the same order of complexity. Then you can talk about their order of appearance in the fossil record and their genetic complexity and guess what? All of these are also in the exact same order. What a coincidence!

It is truly amazing that those who are against evolution sometimes claim evolution bases everything on chance and randomness. Yet, the moment you remove evolution from biology, it truly becomes a network of coincidences and nothing more than that. In a sense, evolution is what chance and randomness from biology and gives structure, laws, processes that allow us to explain the incredible diversity we see in nature.

Evolution is the Basis of Biology and Explains Life
Evolution is the Basis of Biology and Explains Life (Pixabay)

These are only the beginning of the reasons why we must teach evolution. Because by not doing so, we are doing excessive harm to the understanding of biology among the next generations. Evolution is the unifying force in biology. And those who do not understand evolution cannot understand biology. Those who do not understand biology cannot understand who they are. Those who do not understand who they are cannot understand their past. And those who do not understand the past cannot understand the present, or the future; therefore, cannot understand how they fit in this world. We must do the right thing for our children and for the future generations and teach evolution at every level where we teach nature, ecology, and biology.