The Four Steps of Evolution
Evolution Is the Systematic Progress to Survive Environmental Change
Sep 2, 2009
Charles Darwin developed the theory of evolution over a period of 25 years in the late 1800s. Many people find the theory of evolution confusing. What is survival of the fittest? What is natural selection? Why are there no examples of evolution in action? In the following it will become evident how evolution works, starting at the DNA level.
DNA Changes
Evolution starts at the DNA level. It occurs there because there are environmental factors that favor development in one way over another. Evolution starts with changes in gene behavior and hence in DNA replication. Genes change because the DNA sequence that is supposed to be copied from one set to another gets altered. The copy is not perfect. This introduces alterations or mutations into the gene sequence.
To see this, here is an example. Many have seen children born as conjoined twins. Conjoined twins can be used as a test to see if it's possible to show "evolution in action". This is not to say that conjoined twins are always a product of genetic modification, only to ask what the implications would be if they were. If the gene copy were perfect, the gene mutation leading up to conjoined twins would not occur. Assuming the mutation has occurred, this thought experiment of seeking an example of evolution in action can be continued.
An Evolutionary Change Provides Better Chances of Survival
The conjoined twins mutation on its own is not an example of evolution at work. It is a genetic mutation, a change at the DNA level.
What would it take for this to be a step in evolution? It would have to create an advantage in survivability for the conjoined twins. This would be step number two. Clearly, this would be very hard to do in nature without extraordinary parental effort. There is no environmental or survivability advantage derived from having the conjoined attribute. Would being conjoined offer a better chance of surviving than not being conjoined? It would not, and so it is not an evolutionary change. That is the point of an evolutionary change: it has to give the recipient an advantage of surviving that is lacking in those that don’t have the change.
But for the sake of argument, assume that having a conjoined twin is an advantage in nature, is this enough to say that there has been evolution? No it is not. This leads to a further test.
Creating Offspring
Assuming that the conjoined twins managed to survive, now they must be able to reproduce. The next step in the evolutionary process is that their children would also have to be conjoined. For evolutionary change, the change has to be replicated from one generation to the next. Offspring have to be like their parents. In other words, the evolutionary process does not stop with one generation, it must continue into the next generation; it must even continue into the next one after that. If parents cannot produce similar offspring, then the line of change ends with them.
Again for the sake of argument, assume that the conjoined twins reproduce, and their offspring are conjoined twins who also produce conjoined twins. This is still not evolution.
Multiple Recipients of Change in the Same Initial Generation
Still with these three steps working if you only have one example of change, one set of conjoined twins, you will not be able to create a species. That is the fourth and final step.
There have to be multiple recipients of the DNA change. It has to affect others, not just one single organism. Whatever caused the initial DNA mutation cannot be isolated to just one example. The change must affect more than one individual.
Creating a species is what evolution drives towards. It is not just a change but a change in multiple life forms that creates a new species of life; it is this change that gives a species an advantage in the environment. Nature must produce multiple conjoined twins in the same initial generation. Then the cycle repeats itself. When multiple conjoined twins are born generation after generation, then there can be a species. Now you have had evolution.
But as one can see, the birth of conjoined-twins fails to satisfy three out of the four steps of evolution. It is a genetic mutation (step one), but that is all. It does not grant any special survivability traits, the children of conjoined-twins aren’t conjoined, and the birth of conjoined-twins does not occur frequently in nature; instead they are quite rare.
Natural selection is the mechanism by which survivability of a species is made possible. It does not mean that the life form or species will automatically survive, it means that the life form or species that adapts the fastest and the best to the changes will have a better chance to survive.
Evolutionary Time Scale
Evolution takes time. It does not work like gravity, where you can see an apple fall in real time. The time scale for evolution can take multiple generations to occur. This could be years, and in the the case of humans millions of years. Evolution in action does not occur at the macro level, where one can see instant real time change, it occurs at the micro level, where one must methodically wait to see the changes slowly unfold.
Evolution takes place in four steps.
- DNA modification which
- gives survivability advantages followed by
- producing offspring with the same trait and finally
- there are multiple recipients of the same trait where a species is created.
Evolution is about creating a species, not just changing one individual. Each one of the four steps is necessary.
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