|Image Credit: Helen S. Cooper|
We’re familiar with the standard pop culture aliens from the movies and TV. The similarity of those alien depictions to humans has been under criticism for years by astrobiologists. Just this week, a group of Biologists at the University of Oxford said that there may be some key aspects of the development of Earth species that we may be able to apply to alien lifeforms. Futurism.com had a write-up recently.The paper, titled “Darwin's Aliens,” is published this week in the International Journal of Astrobiology. You can read the whole article here. Authors Samuel Levin, Thomas Scott, Helen Cooper and Stuart West pick through elements of human evolution to find actions that might apply on other worlds. The most obvious is natural selection, and thus the nod to Darwin in the title. The authors hypothesize that mechanistic features of lifeforms (multiple functional parts- the biological things that allow a creature to live and reproduce) would likely develop on alien planets in the same way they develop on Earth- through variation, differential success and heredity. If reproduction is an intrinsic part of life everywhere, then natural selection would be as well. The authors use the term directional force, meaning that organisms find better ways to reproduce in order to survive. It all comes down to survival, a foundational part of life here on Earth, and perhaps so on other planets.
|Image Credit: Helen S. Cooper|
So what might these alien creatures look like? The authors don’t rule out some similarity to humans. After all, we are the product of thousands of years of natural selection. But the geology and atmosphere of a planet will also dictate how lifeforms develop. The paper includes a couple of drawings of hypothetical alien life designs by co-author Cooper. You can see in those pictures a rendering of multiple functional parts, which in advanced life forms provides the ability to manipulate surroundings. The paper makes a distinction between simple alien life and complex alien life:
“We have established that aliens will undergo natural selection. It also seems reasonable that, given the sliding scale from replicating molecules to large creatures with many body parts and beyond, some alien discoveries would be more interesting than others. In particular, the more complex the aliens we find, the more interesting and exciting they will be, irrespective of whether they appear anything like the life forms on the Earth.”
The authors conclude with a caution to avoid what they call “circularity” in thinking about the development of alien life. If natural selection is a widespread action in the universe, then alien life will also have a “nested hierarchy of entities” as we have on Earth. In short, organisms would move through a ladder of development that not only creates complexity, but demands it as a means of survival and success.
Does this mean that we won’t be shaking hands with E.T. or one of those popular alien “grays” as the UFO folks like to call them? Not necessarily, but given the potential differences in the chemical composition of other planets, we had best broaden our imaginations and use the teachings of Charles Darwin to guide us in our speculation.