This text was initially printed at The Conversation. The publication contributed the article to House.com’s Skilled Voices: Op-Ed & Insights.
The TV collection Alien:Earth has launched numerous new creatures to the a lot liked, albeit terrifying, Alien franchise.
All species in the series draw inspiration from real living organisms and processes seen on Earth, but crank it up to the extreme. We therefore won’t explore all those parallels, but instead focus on how plausible the organisms are in terms of underlying processes such as physics, chemistry, metabolism and evolution.
1. The tick
Our most plausible creature is the large blood-sucking tick. On Earth, the deer tick Ixodes do swell to the dimensions of a walnut when feeding, which isn’t too totally different from the Alien:Earth tick. Within the present, we see it assault the jugular and shortly tackle a few pints of blood.
The maybe surprisingly fast loss of life of the unlucky prey probably outcomes from hemorrhagic shock as a consequence of how shortly the blood is misplaced. It’s potential that some type of chemical agent (maybe an anticoagulant, as has repeatedly evolved in blood predators on Earth) can also be injected. We do see a defence mechanism in episode 5 the place the ticks launch an airborne toxin to forestall them being faraway from their host. Chemical defenses like poisons and venom are frequent in animals and vegetation on Earth to discourage predators.
In later episodes, we see it break containment (with the assistance of one other alien) however we’ll assume it’s merely in search of a physique of water to put its tadpoles in, moderately than exhibiting intelligence. Horrifically, we see nothing that fully prohibits a life type like this.
2. D. plumbicare (the plant pod)
This creature, which as found and named within the present by the crew of the USCSS Maginot, benefits from not having been seen much (at the stage of writing, we have viewed the first six episodes). As the series progresses, it could move down our list. Initially, the character Kirsh questions whether it is flora or fauna. The science officer’s analysis ultimately shows they classify it as a carnivorous plant. Its green color could indicate it also uses chlorophyll the way photosynthetic organisms like plants do on Earth.
However, a near spherical body is in fact the worst structure for photosynthesis. It lacks any of the surface area enhancing adaptations you’d expect from a photosynthetic organism, such as leaves. This would be particularly important given it appears to hang underneath covering structures like cave roofs. Perhaps this is why it needs to capture prey: rather than evolving more efficient light capturing mechanisms, it instead alternates between photosynthesis and predation, depending on the resources available.
This is known as mixotrophy in science, but is a feature only of single-cell organisms on Earth. “Carnivorous” vegetation should not mixotrophs as they merely supply compounds like nitrates, potassium and phosphorus from captured bugs, moderately than carbohydrates. Animals are heterotrophic, which means they get power by consuming different organisms.
Some organisms, resembling corals, have bacterial symbiotes – “pleasant” parasites – that may photosynthesize power for them from the solar, which might be the case right here.
3. Trypanohyncha ocellus
T. ocellus is the lovable little eyeball octopus parasite. It attacks its host, removing an eyeball and then takes over entirely via connections to the brain.
This may seem like pure science fiction, but there are parasites on Earth that replace body parts and even management their host’s habits. Nonetheless, the latter are often comparatively easy organisms, just like the Ophiocordyceps fungus the place taking up the mind of one other animal is a needed a part of their life cycle. The behavioral modifications these parasites induce are simple, resembling shifting the host in the direction of mild, water or the scent of a predator.
Toxoplasma gondii, for instance, is a parasite that alters the habits of mice, making them much less avoidant of the scent of cat urine. The contaminated mice are due to this fact extra more likely to be eaten by cats, which then unfold long-lasting parasite spores of their feces.
T. ocellus, in distinction, could be very cell, very smart and robust, displaying habits like monitoring conditions and distracting people. This habits is believable with distributed ganglia (clusters of nerve cells) within the tentacles, much like octopuses.
The size of those tentacles, nonetheless, exceeds that of comparable constructions on Earth, resembling chameleon tongues, and is due to this fact considerably implausible (however nonetheless extremely cool). Our principal difficulty right here is why it must be parasitic in any respect – that is finally a formidable life type with out requiring that.
4. The fly
First seen in episode 6, the fly appears to consume metal and metal ores and it pre-digests its food by spitting an enzyme, similar to flies on earth. Our main issue with it is that it’s unclear whether this is a supplement (such as iron and other trace elements in our diet) or a main energy source.
There is a process on Earth often known as chemolithotrophy (actually “rock consuming”) by which power and biomass manufacturing could be harnessed by oxidation (elimination of electrons from) of geochemicals – together with iron, manganese and different metals.
On Earth, that is unique to single celled archaea resembling Ferroplasma and micro organism resembling Acidithiobacillus, organisms usually related to very gradual development. Multicellularity is energetically demanding, to not point out flying, which means steel oxidation shouldn’t be a really believable power supply for the fly.
After all, the steel might merely be a complement, albeit a really giant one, wanted to create a metallic shell. Biomineralization of iron compounds into the teeth of marine molluscs like chitons and limpets, who want laborious enamel graze on rocky surfaces, is effectively documented. An identical mechanism might clarify the laborious metals within the Xenomorph’s exoskeleton (which it wants to have the ability to scratch by way of the steel in a ship’s hull).
5. The Xenomorph
Very crudely, if we assume it has a similar metabolic efficiency to humans, and that it weighs roughly 100 kg, then it would need to consume and convert millions of calories of food (over a ton of pork-like meat) in what seems to be a few days at most. Of course, it could have a much higher metabolic efficiency than humans, though it would always be bound by the conservation of mass and energy. You can’t acquire more biomass than you consume. And we never see it eat, not even its initial host.
Circumventing this would require an ultra dense (entirely hypothetical) energy source that it carries with it from the egg (Ovomorph). But energy has to enter the system at some point, implying the Queen would have to eat or capture huge amounts of energy somehow.
Another issue for the Xenomorph is that, if it did need to eat the huge amount of creatures it kills, it would rapidly deplete any prey resource and there would probably be no stable ecosystem that could support it. However, in the expanded universe, it seems that the Xenomorphs are artificial beings, created from a bio-weapon intended to obliterate an ecosystem, leaving a clean slate. In which case, they seem very effective.
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