Lizard shows us how animals can rapidly evolve in the human environment

A research study published in the Proceedings of the National Academy of Sciences journal, reveals that the Puerto Rican crested anole (a small green-brown lizard) has evolved over a very short period of 80 years to better survive in the human environment.

The scientists looked at this lizard species living in the jungle and in urban regions. The cities in which they were studied have been in existence for about 80 years which is the equivalent of 100 lizard generations. The equivalent of about 2,000 years for humans.

Puerto Rican crested anole
Puerto Rican crested anole. Photo by Dan on Flickr.

Over this short space of time, they found that more than 30 genes changed. And there was a common change in these genes across three unrelated city-living groups suggesting that they had evolved and were continuing to evolve separately.

The study looked at 96 individuals of this lizard species. The evolution to cope better with the difficulties of metropolis living included growing longer legs for running from dangers such as dogs and cats and evolving bigger toe pads to enable them to cling to smooth surfaces.

The human environment contains far more smooth surfaces such as the plate glass of skyscraper windows compared to the natural environment of the jungle in which lizards climb trees covered by rough bark.

The lead author of the study, Prof Kristin Winchell of New York University, said that she was partly motivated to better understand how humans affect animals who live alongside us.

She added:

“The urban environment is so drastically different from where these animals have evolved. It’s hotter, it’s dominated by buildings with flat surfaces. There’s humans. There is pollution. All these create a unique evolutionary selection.”

In reference to the short duration during which these lizards evolved anatomical differences to those of the jungle lizards she added the following comment:

“This is really, really fast”.

As mentioned, the evolutionary process took 2,000 years in human terms and 80 years in lizard time. A mere 100 generations. In contrast scientific evidence shows that the physical and behavioral traits shared by all humans originated from apelike ancestors and evolved over a period of approximately six million years.

Of course, you have to think of the many other animals who live alongside humans and with humans. How have they evolved? I know quite a lot about domestic cats. They’ve certainly evolved too with new coat types for instance. The original ‘domestic cats’ were all spotted tabbies. Now look at the coat range. And they are squatter and less rangy. More decorative 💓. And they are less intelligent because they are pampered. Sad.

The interesting aspect of this research is to try and visualise how our companion cats and dogs will have evolved in say 5000 years’ time. What will they look like in the year 7000!?

Below are some more articles on evolution.

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Post Category: Evolution