Life is all about Change


In an experiment in Michigan State University, scientist Richard Lenski started growing a group of E. coli bacteria in 1988. The bacteria have kept reproducing since then, making the incredible amount of more than 50,000 generations. But there is a purpose to this experiment: study evolution and answer a very simple question: Is there an end to evolution?

Lenski grew about 12 different groups of E.coli bacteria in a simple, constant medium. He used bacteria because this type of organism grows and reproduces very quickly and they are fairly easy to manipulate and study. It was important that the environment was kept constant, because any little change could affect the evolutionary process.

After every 500 generations, a sample was taken and frozen, so at some point, a group of bacteria from different generations was put together and their aptitude at surviving compared to each other is be measured.

The results are very surprising and revealing. Every generation, Lenski found, had a minor improvement over the former one. The grandson was always fitter than the grandfather; no matter how many times the experiment was repeated. But this was expected. The news is that, at some point, the improvements were less and less obvious, so even though there were still changes, they weren’t so useful or noticeable with each generation.

E. Coli bacteria

E. Coli bacteria

This is an example of power law, a mathematical term used to describe a sequence that is ever increasing, but the amount by which it grows, decreases.

This information is interesting because, up until now, it was thought that organisms had a limit as to how adapted they could be. This applies only to constant mediums. In the real world, there is always going to be changes, because the environment or the habitat changes all the time, however small the changes are. So the answer to our first question was no. There are always changes around us, so we are always going to be changing. Even if the world stopped changing in every minute detail, we would still be developing new ways in which to be fitter for survival.

Some people say that this could not be applied to humans or other species, but the idea is the same. Just like your parents said, there is always something you can do to be better.

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