What Is Evolution, and What Is Not?

From the Lecture Series: Understanding the Misconceptions of Science

By Don Lincoln, Ph.D., University of Notre Dame

What is evolution? The simplest definition is how species change to adapt to the changing environment and survive. Those who fail to evolve, become extinct. Those who successfully evolve, turn into a different version of themselves. But do species also turn into each other?

Wildebeest crossing the Mara River during the annual great migration.
Evolution is how species changed eventually to fit the new environments, and became completely dissimilar to their ancestors. (Image: Jane Rix/Shutterstock)

Being a well-studied topic does not mean there are no misconceptions about it. Evolution is commonly misunderstood or wrongly explained to answer ‘what is evolution?’

What Is Evolution?

The simplest definition of evolution is how life changes under the pressure of the surrounding environment. The purpose is to survive, but there is no final goal for evolution. Evolution does not tend to make all species intelligent and complex until a certain level. It just happens when living conditions change, and adapting to the conditions becomes a do-or-die.

Learn more about humans are not peas: myths about genetics.

How Does Evolution Happen?

For example, if there is a swamp full of salamanders, enough food for them, and perfect climate, all salamanders survive and reproduce. However, if a long-lasting drought happens, things change.

By nature, some individuals in a species are more resistant to difficult living conditions. When there is less water, salamanders that can tolerate the conditions and eat different kinds of food survive—those who cannot, die out. The surviving salamanders reproduce under the new conditions and the babies that survive also have the same flexibility.

Through time, salamanders change to adapt to drier conditions—they even start to look different. After some generations, the population of salamanders living in drought increases, the inadaptable ones all die, and the new salamanders look significantly different from their ancestors living in the swamp with plentiful food and rain. This is called evolution.

This is a transcript from the video series Understanding the Misconceptions of Science. Watch it now, on The Great Courses Plus.

Evolution Vs. Religion

Believing in a religion does not necessarily mean that a person is against evolution. However, some religious people are not comfortable with the idea of evolution. For example, in the Christian Bible, in the book of Genesis, chapter 1, verse 26 refers to God’s intentions in creating humans as His image to rule over all creatures.

Sometimes people who strongly disagree with evolution try to create an environment where misunderstanding evolution becomes a value. To prevent this, one must first know what evolution is and what questions it should answer. The most common question that religion is concerned with, but evolution is not responsible for, is how life began.

Learn more about if thermodynamics disprove evolution.

Abiogenesis: Life from Non-Living Matter

Planets of the solar system.
Evolution is not supposed to explain how life began, it only explains how life survives. (Image: Vadim Sadovski/Shutterstock)

Evolution does not explain what happened before life began. It explains how life changes to survive. The term referring to how life began is ‘abiogenesis’. Darwin thought life began in a small warm pond with all kinds of ammonia, phosphoric salts, light, heat, electricity, and other matter that could chemically form a protein compound capable of further change. However, life has probably formed in a chemically-volatile environment.

Deep-sea vents—places at the bottom of oceans where magma is very close to the surface—are a more reasonable place for life to have formed. The heat and the active sulfurs and other elements combined and life began. Did the simple creatures there evolve to one another until a more complex one was formed?

Learn more about whether there is a theory of everything.

Does Evolution Turn Species into Each Other?

A very common misconception about evolution is that animals turn into each other: a fish into a lizard, a lizard into an animal, the animal into a monkey, and the monkey into a human. A simple question that arises following this concept is why chimpanzees still exist if we evolved from them? Why did not all chimps turn into humans? The answer is that humans were never chimpanzees.

Human evolution vector drawn illustration.
How monkeys turned into humans is a very common misconception about evolution. The truth is, no human was ever a monkey. (Image: elyomys/Shutterstock)

To make it simple, one can imagine a family tree. The lowest level of the tree comes from a father, who came from his father, who came from the great-grandfather, and so on. The higher we go up the tree, the more complicated it becomes. However, it is certain that the 20 great-grandfather died centuries ago. What goes unnoticed is the complexity of the tree and the other relatives involved.

All the fathers in the tree had relatives that could have children of their own. These children are cousins, second cousins, and so on. Thus, they might share the same 20 great-grandfather, but they are not the same, and they might even come from different countries. Add to that the same complexity on the maternal side, which is completely ignored in the family tree, and the true complexity of evolution emerges.

Chimpanzees are our distant cousins that look as different from our shared ancestor as do we humans. Conclusively, evolution is not how life began or how creatures turn into each other. It is how species change to survive.

Common Questions about What Is Evolution

Q: What is the best definition of evolution?

Evolution is simply a description of how life changes over time under the influence of pressure from the environment. It does not necessarily refer to life getting more complicated and simple creatures becoming extinct; it refers to how they adapt to the new conditions.

Q: Can one species evolve into another?

Species do not turn into each other. What evolution brings is the creation of different species from the same ancestors until they are so distinct from each other that they no longer resemble either each other or the common ancestor.

Q: Why is evolution important?

The importance of evolution lies in what evolution is: the changes that occur in species to adapt to new environmental conditions. Without evolution, every living thing would get extinct.

Q: How does evolution happen?

Evolution happens when environmental conditions change, and species need to adapt to the new conditions slowly to survive, otherwise, they will die out.

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