Convergent Evolution is an instance in biology where two unrelated (or very very distantly related) organisms each evolve the same trait. I’m grossly simplifying that point but you get the idea right? Things like eyeballs have been evolved separately multiple times in Earth’s life. The reason for this is probably that seeing is way more beneficial than not seeing. Senses in general are usually great.
There are situations where you won’t need a certain sense. If you live deep down in caves that see no sunlight you’ll likely lose any eyeballs you’ve got. More accurately some of your offspring will have slightly shittier eyes but still do fine breeding. Perhaps losing their eyesight will cause their other, more vital, senses to be better. Like little daredevils trying to bring justice to your new cave land over generations.
What is my point in this little ramble? It’s that you should write about things late at night and set them up to be posted the next day. You are just asking for failure. Once we get past that we look at the relevance of CE (Convergent Evolution) to the cosmos as a whole. Why does CE happen at all? It happens because physics, while wildly vast, doesn’t really have all that much variance. Yes there are MANY different tiny slivers of light but the range of light that organisms can safely live in is pretty small. You won’t find many organisms that see in Gamma because gamma radiation would kill off the organism before it got that far in its genetic race.
We can safely assume that most planets will be near stars. Gravitation tends to be finicky about that. Little things gather near bigger things, or more accurately near denser things. I suppose Black Holes are “functionally” large because their area of effect is pretty impressive. But literally they are not. Anyways…
If planets are near stars we can then assume they’ll be bathed in light at some level. If the light is bright then we are looking at animals that’ll likely have a focus on eyes that is about as pronounced as most living things on Earth. Well…maybe I shouldn’t say most…I’m not sure how many insects have eyes. You get my point I suspect, regardless. If you were to land on a habitated alien planet and not find the predators with forward facing eyes (more helpful for tracking your prey) and prey with sideways facing eyes (more helpful for tracking your entire surroundings) I’d be so stunned.
We are talking shocked on a level where I just might crap my pants.
Next does the planet have an atmosphere? This is probably but there are situations where it might not. Europa doesn’t need one (nor does it need sunlight). So if you found life on Europa it would likely fall within the constraints of deep ocean life on Earth. I don’t know a great deal about that but if you were to find life on Europa and it didn’t look familiar to you, as a deep sea biologist, I’d again crap my pants.
I may need to examine this pant crapping pavlovian response I’ve built up to surprise and reflect on my life as a whole.
If the planet DOES have an atmosphere we can safely assume it has noise. Sound travels through a medium, sure you can hear in water, but I don’t think this is necessarily helpful for a lot of animals. I know I can comprehend fuck all when I am underwater. Then again I’m not built for it.
If the planet has functional noise we can safely assume that the organisms there will have ears. These ears will likely be very very close to their central information processing system (ie. brain). Eyes too. You want the least amount of latency between your sensory organs and your “brain”. Because of that the odds that this new life would have a dedicated “head” region is probably pretty damn good.
Sure, maybe they all won’t, but I bet a lot of them will.
Reproductive organs might be a wash. I don’t know if there is any benefit to having them near the base of animals. But a lot of us do. So if there IS a benefit to that you can be darn sure that the space genitals we see will be roughly where we expect them to be.
Waste handling is going to be as far from the intake of the animal as humanly possible. Again, having your mouth very close to your brain is helpful. It reduces sensory time and helps build a very strong connection between what you are eating and how that eating makes you feel. A strong connection is more likely to bolster your desire to eat and make you a much more energetic partner than your mouth-attached-to-ass mutated brethren. Evolution will treat you kindly. You’ll still die, but at least you got to breed first.
The natural response to all of this is “Dear god, see a shrink.” Or if you happen to be more eloquent than I am “This is very Earth Centric.”
Light and Sound are not unique to Earth. The effects of high energy particles are not unique to Earth. Physics as a whole is not unique to Earth. The odds that biology is not similarly universal, because it is a response to the universe, seems to be the exact kind of hubris being accused above.
I don’t think we are special. CE reminds us that life will inevitably travel down a certain path. I would bet with a fairly high level of confidence that if you knew the exact composition of a planet you could reasonably well guess how the life will look there. Furthermore while this science will start out weak there will come a time where you can basically pump a few data points into a PC and have it model you the exact life you’ll see depending on a certain amount of time.
Not because we are magical space wizards that can see the future but because Biology is just as universal as Physics. It’s just a bunch of booleans waiting to be flipped. Sure the number of toggles is vast but there are plenty of vast things that we’ve overcome in my lifetime. This’ll be another of them.
Once we do get into Europa and (probably) find life I’m confident I can watch the video feed in public. Because any chance of pant crapping is so vastly outside of my ability to accept that it might as well be about [insert name of faith that badmouthing wouldn’t offend you here] being found to be objectively true.