Aliens often look like us in the movies – will they look like us in real life?

And when they do not look like us, they look like things that are familiar – if they may be annoying – such as insects, reptiles or even squid.

This could simply be due to the limited imagination, and perhaps the budgets, of Hollywood creators.

But it could also be something we could expect to see if or when we encounter extraterrestrial life.

The argument is simple: The evolutionary forces and rules that made us as we are must apply to life on other planets. The laws of nature are common throughout the universe.

This is the case of the zoologist Arik Kershenbaumof the book, called The Zoologist’s Guide to The Galaxy: What Animals on Earth Reveal About Aliens and Ourselves.

Kershenbaum is a lecturer and fellow at Girton College at the University of Cambridge in England. Talk to me Oddities & Quarks host Bob McDonald.

Zoology and the study of extraterrestrial life may seem like two different subjects at first glance. What inspired you to write a book that combines the study of both?

Well, the study of zoology, or the way we zoologists pursue our science, is always asking “why” questions. Asking why animals are as they are, why they look like they look, why they behave as they do. And the answer to all these “why” questions always comes down to evolution, to the different ways in which evolutionary forces act on these animals.

Thus, it is not really so great to see that the evolutionary forces that we understand from studying animals all this time on Earth, these same forces are universal. These are the species that will make the animals on Earth eat each other. They will make creatures on other planets eat each other because the fundamental laws are still the same.

Carl Sagan believed in life on other planets and that they would indeed have similar characteristics to life here on Earth. But now we learn that the planets, even those within our own solar system, are actually very different from Earth. So how can that be? How can extraterrestrial life be like ours in so many different worlds?

The interesting thing here is that evolution and the process of evolution and the rules by which evolution operates are almost independent of the underlying biology. It is more or less independent of biochemistry. It depends on the type of metabolism or the type of chemicals used.

You do not need DNA for evolution. Okay, there are many different ways in which evolution could work with different kinds of chemicals, different kinds of chemicals. You could have DNA-based animals like ours. You could have creatures based on a different chemical that transmits information from one generation to the next. You could have water-based animals, maybe even some other solvent they could use. However, the evolutionary processes will still be the same, the survival of the fittest.

How will what we know about the general principles of life here help us to know what to expect when, supposedly, we meet clever aliens?

Well, when we meet intelligent aliens – if we were to meet intelligent aliens, then the situation is slightly different, because any alien species or any alien culture that has the technological ability to come and visit us is technologically advanced with access to resources our imagination. So I think that’s really unlikely.

We may be able to communicate with intelligent alien cultures, if they exist using radio communication, for example. If we were to come in contact with an alien civilization, then my great hope is that they have their own David Attenborough counterpart and that they can send us a lot of TV documentaries about what extraterrestrial life is like on their planet. And then we could compare.

Science fiction has fun with aliens. Have you seen any elements out there that make you think, “is there a good idea?”

The role of science fiction is to allow us to suspend skepticism a little so that we can look at difficult aspects of human nature. You know, you have a Vulcan that has no emotion, and that allows us to explore what that means. Klingon, which is warlike and driven by honor, makes it an easy way to explore the difficulties of being human. So, in that sense, most science fiction is not about what extraterrestrial life might be like.

But having said that, you could also say that if I am right, and if many of the fundamental laws about what extraterrestrial life will be like are the laws on Earth, and in particular, if they are intelligent technological extraterrestrial life must has gone through a similar kind of evolutionary history to ourselves – certainly a similar social history to us – then perhaps we can expect that extraterrestrial intelligent life forms will be more like ourselves.

And then perhaps it is not so absurd to think of them as slightly different people with different characteristics, very different priorities, different perspectives. And in that sense, in fact, I think these science fiction depictions of aliens are really quite stimulating.

You ask “Can we continue to trust our intelligence to save us from any impending ecological disasters?” So do we need help from artificial life forms out there?

Well, one of the most famous solutions to the big question – “Why haven’t we discovered aliens? If they are alien civilizations in the universe, why haven’t they contacted us?” – one of the most famous solutions to this paradox is that it is very likely that civilization, once it has reached a certain technological progress, will simply self-destruct.

And from our experience, this seems to be a very reasonable assumption. I mean, we’re not doing a good job. The outlook for the human race does not look good. Whether we will still be here in a thousand years is a question to which we do not know the answer. So, it could just be that once you reach a certain level of technological dominance in your environment, but you have not reached a level of complexity and wisdom to be able to protect your environment, then you are essentially doomed.

Produced by Mark Crawley. Q&A has been processed and condensed for the sake of clarity.