History ArtisticLicenseBiology / Literature

** Dragons are very clearly carnivorous predators by nature, but those serving in Argonathi legions are fed with rations that mainly consist of vegetarian dishes like oatmeal and noodles. They are also spiced with akh, but it's definitely not made of meat either. This means, by all logic and laws of nature, that dragons should be severely malnourished regardless of the amount of food they ate. This is because the digestive system of carnivores is -- plainly and simply -- not adapted to digest plant-based food. If they ate it, it would just go straight through their bodies without providing them with any nutrients (at best) or give them food poisoning (at worst). However, dragons of Argonath seem to have no trouble with this, aside from their constant complaints that there isn't enough akh in their meal.

* ''Literature/JeffTheKiller'': The title character has a severely burned face, a GlasgowGrin, and severed eyelids, the last two of which are self-inflicted. This does not impede him in any way, even though such injuries would lead to blindness and death by sepsis in RealLife. Not only that, but after being covered in bleach and alcohol, then set on fire, all that happened was Jeff's face was bleached white. The actual results would have been [[BodyHorror far, far more gruesome]].

* In ''Literature/{{Nutshell}}'', the unborn protagonist's mother drinks wine while pregnant. Surprisingly, rather than cause birth defects, it just dulls the child's senses for a short amount of time.
* The first ''Literature/ThePaperMagician'' book depicts a valve between the second and third chambers of the heart, similar to the valves between the first and second chambers and the third and fourth chambers. This is not how human hearts work. The heart is divided into two parallel halves; the right half receives deoxygenated blood from the body and pumps it out to the lungs to pick up more oxygen, while the left half receives the reoxygenated blood from the lungs and pumps it out to the rest of the body. If you can get from one side of the heart to the other without actually ''leaving'' the heart, '''something is wrong'''. And this is after a character in the book has spent time ''specifically studying'' anatomical diagrams of the heart, [[spoiler:and has ''crafted a working prosthetic heart based on that knowledge'']], which gives the impression that the character has done more research than the author who wrote her.
* In the ''Literature/PointFantasy'' book ''Brog the Stoop'', it's mentioned that a female "Stoop" (vaguely elven creatures with blue skin) can only bear one "Stoopling," which would mean every generation is half the size of the previous one, thus leading to extinction pretty quickly.
* In ''Literature/PrinceCaspian'', Reepicheep the talking mouse has lost his tail in battle, and he argues with Aslan over whether it needs to be regrown. Both of them seem to think a mouse's tail has no practical value and is of use only as a badge of honor or vanity, but the tails of mice and rats are actually important thermoregulatory structures, without which he'd be quite vulnerable to heat stroke. (This is touched on in [[Film/PrinceCaspian the movie adaptation]]: "Well, it's not just the honor. It's also good for balance, and climbing...")

* Early in ''Literature/ArtemisFowl'', Holly Short has a CharacterFilibuster denouncing sewage treatment as a [[GaiasLament horrible violation of Mother Earth]], inspiring FridgeHorror in readers familiar with modern Germ Theory. When the elves are ''this obviously wrong'', someone should definitely be [[CantArgueWithElves arguing with them]]. It's possible this is just intended as DeliberateValuesDissonance, as it doesn't take much analysis to see how hypocritical the People tend to be with their views on humans.

* Literature/BookOfGenesis:
** The TropeNamer of the AdamAndEvePlot which ignores the problem biology and genetic diversity poses, making it impossible for the human race to have started from just two people.
** This problem occurs again in the story of Noah where not only is the human race suppose to be reborn from eight people (Noah, his wife, their three sons and their wives) post-flood, but also the genetic bottleneck a breeding pair of every animal on the ark[[note]] with only a handful of known exceptions being capable of asexual reproduction.[[/note]] would face.

* Medb, Queen of Connacht, from ''Literature/TheCattleRaidOfCooley'', is defeated because her period saps the strength of her army. The biology artistic license comes about because her period makes her ''piss'' blood. Enough to flood three parade grounds in fact.

** Both [[Literature/HarryPotterAndThePhilosophersStone the book]] and [[Film/HarryPotterAndThePhilosophersStone movie]] of ''Philosopher's Stone'' feature a snake that winks at Harry. Most snakes can't wink (certainly not the boa/python depicted), owing to a lack of eyelids.

* ''Literature/{{Replica}}'': The bad guys repeatedly try to get hold of Amy's super-DNA by ''cutting her hair and fingernails''. The installment in which her DNA reverts to "normal" after getting her ears pierced... wait, what?

* ''Literature/{{Twilight}}'':

* ''LightNovel/HeavyObject'': Major Frolaytia Capistrano has been using her military career partly as a way of hiding from her legion of suitors since women of her family are very likely to produce boys (making her attractive as a BabyFactory for [[HeirClubForMen nobles needing heirs]]). This is completely impossible: one of the most basic facts of human reproduction is that it's the ''male'' Y chromosome that determines biological sex (monosomy and trisomy syndromes notwithstanding); a woman can only provide an X chromosome.

* ''Franchise/StarWarsLegends'': Mynocks are intensely allergic to helium, and die nearly instantly on contact with any amount of it; this is stated to be the primary reason why they can't establish themselves on planets. Helium is a noble gas, a class of elements notable mainly for their intense inertness and difficulty in reacting with any other substance, which makes it very difficult for them to have any effect, good or ill, on a living organism, and for being rare to the point of nonexistence in planets due to its lightness making it impossible for most planetary gravities to keep it from leaking off into outer space.

* ''Literature/StarWarsLegends'': Mynocks are intensely allergic to helium, and die nearly instantly on contact with any amount of it; this is stated to be the primary reason why they can't establish themselves on planets. Helium is a noble gas, a class of elements notable mainly for their intense inertness and difficulty in reacting with any other substance, which makes it very difficult for them to have any effect, good or ill, on a living organism, and for being rare to the point of nonexistence in planets due to its lightness making it impossible for most planetary gravities to keep it from leaking off into outer space.

* In ''Literature/{{Replica}}'', the bad guys repeatedly try to get hold of Amy's super-DNA by ''cutting her hair and fingernails''. The installment in which her DNA reverts to "normal" after getting her ears pierced... wait, what?
* In ''Literature/SalemsLot'', Dr. Cody, who is not depicted as an ignorant quack but an at least semi-competent professional, says, "Why should your head hurt? Your brain doesn't have any nerves." First off, if your brain had no nerves then it would functionally be useless. He means that your brain doesn't have ''nociceptors'', which is true, but doctors universally knew very long before the book was written that there are all sorts of reasons why your head still hurts. For example, while the gray matter ''itself'' doesn't feel pain the blood vessels that run through the brain do. Ice cream headache is one example of this type: the sudden rush of cold to the head makes the vessels temporarily painfully retract. Also, sinuses can cause headaches, as can the inner scalp. Very often it's the back of the eyes (which are less round and go further back into the skull than they look from the outside) hurting due to eye strain or what not. The skull can feel pain too, but probably only if you've suffered serious cranial damage. No one with an M.D. wouldn't know all this.

* In the ''Literature/StarTrekNewFrontier'' book ''Stone and Anvil'', it is explained that Mark [=McHenry=] gets his abilities because he is descended from Apollo and Carolyn Palamas. No one else in the line has these abilities because the godhead is carried on the Y chromosome, and all their descendants prior to Mark are female. Females have only X chromosomes, and there's no explanation where Apollo's Y chromosome was hiding out for the intervening century.
* In ''Literature/ASwiftlyTiltingPlanet'', all of the good and significant descendants of Madoc, the good Welsh prince who sailed to America, went native, and married a Native American woman of a tribe called the Wind People, have deep blue eyes -- regardless of their racial background. It doesn't matter if they are 99% Native American, they have deep blue eyes. The evil significant descendants of Madoc's power-hungry brother (who intermarried with the warlike People Across the Lake -- enemies of the Wind People -- and whose descendants intermarried with the native population of Vespugia) have either metal-gray eyes or ice-blue eyes because genetics color-codes eyes according to a person's morality. Uh-huh. The genes for blue eyes of all sorts are dominant, too.
* One of the books in the ''Literature/ThroughWolfsEyes'' series by Jane Lindskold featured [[ConjoinedTwins conjoined fraternal twins]], a boy and girl who had been attached at the hand. This is completely impossible any way you look at it, as conjoined twins are the result of identical twins whose egg failed to split properly; fraternal twins, who are conceived from two different eggs, could never end up attached to each other. Furthermore, RealLife conjoined twins are ''never'' attached at the ends of their limbs, as the developmental error that causes imperfect separation of identical twins happens long before an embryo's limb buds appear.

** During the voyage to Eigo in book four, we learn that dragons are immune to sea sickness, since their ears' labyrinth is different than humans'. They apparently retain balance thanks to movement of small cilias inside while lacking a fluid that our labyrinth holds and which is shaken by movement of a vessel, "disorienting the whole system". This is ''absolutely not'' how motion sickness works. In reality, its main cause is a dissonance between signals you receive from your labyrinth (which tells you that you are on the move) and your other sensory organs, mainly eyes (which tell you that you are not moving). Which is why the best course of action when you're seasick is to stay on the deck and watch the landscape (which you can ''see'' moving), while the worst thing you can do is to stay in your cabin (where ''nothing'' moves, thus aggravating the symptoms). So even if you replace liquid with some unspecified cilias, that does not change anything -- dragons would still be seasick as hell. To dispel any further doubts -- no, the fact that Argonathi dragons are naturally aquatic animals ''does not'' magically give them an immunity to sea sickness, just like the fact that we humans are naturally land animals does not make us immune to getting sick when we're, for example, trying to read in a car. That is because sea sickness does not stem from some malicious properties of the sea, but the fact that you travel it ''by a ship'' -- something which moves independently from your own body and the sea itself, thus causing said dissonance.

* Creator/WayneBarlowe does a pretty good job of maintaining consistent and possible alien biologies in ''Literature/{{Expedition}}''... except for the Daggerwrists. Pregnant Daggerwrists are cannibalistic and are executed by their tribes when their single offspring is born. If you can't do the math, this means that ''at least two Daggerwrists will die for every one born''. Additionally, none of the animals on Darwin IV bar one have eyes, and the one that does appears to gradually be losing them. Given that eyes have evolved independently at least ''five times'' on Earth, and that eyes present a massive advantage to survival in light-filled environments, the lack of eyes on Darwin IV is extremely unlikely.

* Lots of examples in ''Literature/FelicityFlooVisitsTheZoo'':
** Felicity's illness spreads to many different species at the zoo.
** Reptiles get fevers.
** Felicity is very active despite having either a cold or the flu.

** The flu is defined as a cold that simply "got bigger".
* The vampire-like creatures from ''Literature/FevreDream'' seem doomed to slow extinction, as their females give birth to single offspring and always die as a result. Granted, Martin's vampires are actually ''aware'' of this quandary, but that can't explain why their young would evolve the self-destructive habit of clawing their way out of the womb, in the first place. At least the source is clear: that's what they thought about lions in ancient times.

* In ''Literature/{{Gone}}'', it is {{lampshade|Hanging}}d when Astrid points out that there is no gene for shooting lasers out of your hands. Justified, however, when it is revealed that the meteor that carried The Darkness seems to have broken reality.

* Very prevalent in ''Literature/HumanxCommonwealth'', given Creator/AlanDeanFoster's love for inventing species with BizarreAlienBiology without really considering how it could possibly happen. A very major one occurs in the ''Icerigger Trilogy'', when it's revealed that the planet goes through 10,000 year periods of ice ages (that cover the ''[[SingleBiomePlanet entire planet with ice]]'') and global warmings and that every species on the planet has consequently evolved so that they will have phenotypes for both climates- for example, the massive Thunder Eater turns out to be a whale that's able to pull itself along the ice on its tusks. In reality, this is nowhere close to how evolution works- evolution only selects for reproductive fitness in the current generation and will not cause a species to retain a trait that isn't useful now because it might be useful for descendants of the current generation thousands of years from now. The original Thunder Eaters, if they could even survive being stuck permanently out of water like that (which is seriously implausible), would have evolved into an animal that was much more suited for living on arctic ice and not swimming rather than retaining their aquatic adaptations.

** The Faeru species while appearing human is descended from outcast “Fae” who lost their innate magical powers and promptly evolved Psionic Powers.

** 'The Journey' -- Marco starts showing Rabies symptoms far faster than he should have; it takes weeks or months for that to occur.
** In the first book, there's a mention made of Jake's knees reversing the first time he morphs into a dog. Dogs are digitigrade; presumably, the author mistook the dog's ankles for his knees. This mistake allegedly prompted Applegate to start doing better research for the rest of the series.
** A series-wide one: Yeerks take over humans by entering the host's body through the ear and wrapping around the brain. There is no direct passage between the ear and the inside of the skull; to reach the brain, the Yeerk would have to chew, cut, or dissolve through several layers of tissue, which would undoubtedly prove fatal.
* Early in ''Literature/ArtemisFowl'', Holly Short has a CharacterFilibuster denouncing sewage treatment as a [[GaiasLament horrible violation of Mother Earth]], inspiring FridgeHorror in readers familiar with modern Germ Theory. When [[CantArgueWithElves the elves are]] ''[[CantArgueWithElves this obviously wrong]]'', someone should definitely be [[ScrewYouElves arguing with them.]] It's possible this is just intended as DeliberateValuesDissonance, as it doesn't take much analysis to see how hypocritical the People tend to be with their views on humans.
* In Creator/MadeleineLEngle's ''Literature/ASwiftlyTiltingPlanet'', all of the good and significant descendants of Madoc, the good Welsh prince who sailed to America, went native, and married a Native American woman of a tribe called the Wind People, have deep blue eyes -- regardless of their racial background. It doesn't matter if they are 99% Native American, they have deep blue eyes. The evil significant descendants of Madoc's power-hungry brother (who intermarried with the warlike People Across The Lake -- enemies of the Wind People -- and whose descendants intermarried with the native population of Vespugia) have either metal-gray eyes or ice-blue eyes. Because genetics color-codes eyes according to a person's morality. Uh-huh. The genes for blue eyes of all sorts are dominant, too.

* In the ''Literature/PointFantasy'' book ''Brog the Stoop'', it's mentioned that a female "Stoop" (vaguely elven creatures with blue skin) can only bear one "Stoopling," which would mean every generation is half the size of the previous one, thus leading to extinction pretty quickly.

* ''Literature/HereticsOfDune''. Highly oxygenated blood of a normal human is presented as being exceptionally black, while it should appear exceptionally red.

* The vampire-like creatures from Creator/GeorgeRRMartin's ''Literature/FevreDream'' seem doomed to slow extinction, as their females give birth to single offspring and always die as a result. Granted, Martin's vampires are actually ''aware'' of this quandary, but that can't explain why their young would evolve the self-destructive habit of clawing their way out of the womb, in the first place. At least the source is clear: that's what they thought about lions in ancient times.

** Creator/JKRowling, [[WordOfGod says that]] "[[http://www.mugglenet.com/editorials/editorials/edit-wilkins01.shtml magic is a dominant and resilient gene.]]" Given the number of wizards born to Muggle parents (and the extreme rarity of the reverse), this blatantly flies in the face of middle school genetics. You could say that AWizardDidIt (it ''is'' magic, after all), but a better explanation would perhaps be that magic is ''recessive'' and that squibs have mutations that block or repress the magic gene. This may be a whole class of subtrope: treating "dominant" and "recessive" as synonyms for "awesome" and "lame", rather than their proper meaning in genetics, which are "works even if you only get one" and "only works if you get two."[[note]]To be more precise, a dominant gene is one that tells a cell how to produce a protein. Even one dominant gene is enough to code. Two recessive genes mean that there are no instructions, so a protein is not produced.[[/note]]
** Both [[Literature/HarryPotterAndThePhilosophersStone the book]] and [[Film/HarryPotter movie]] of ''Philosopher's Stone'' feature a snake that winks at Harry. Most snakes can't wink (certainly not the boa/python depicted), owing to a lack of eyelids.
* ''{{Literature/Herland}}'': Everyone being born from parthenogenis (aside from this being biologically impossible in humans to begin with) would make them all genetically identical-they'd be natural clones. However, this is not shown in the book, and they're distinct enough that eugenics actually can be practiced.
* Similar to several other examples on this very page regarding single offspring, there is a Dutch book by A.F.Th. van der Heijden called ''Het Leven uit Een Dag'' (Life In A Day). Humans only live one day in the book and can only have sex once, then their reproductive organs will wither away (the woman will get pregnant instantly). Since the humans in that world only get one child, each generation will be half the size of the previous one. Since a new generation only takes a day to grow up and die, humankind would be extinct pretty darn soon.

* Very prevalent in Creator/AlanDeanFoster's ''Humanx Commonwealth'' novels, given his love for inventing species with BizarreAlienBiology without really considering how it could possibly happen. A very major one occurs in the ''Icerigger Trilogy'', when it's revealed that the planet goes through 10,000 year periods of ice ages (that cover the ''[[SingleBiomePlanet entire planet with ice]]'') and global warmings and that every species on the planet has consequently evolved so that they will have phenotypes for both climates- for example, the massive Thunder Eater turns out to be a whale that's able to pull itself along the ice on its tusks. In reality, this is no where close to how evolution works- evolution only selects for reproductive fitness in the current generation and will not cause a species to retain a trait that isn't useful now because it might be useful for descendants of the current generation thousands of years from now. The original Thunder Eaters, if they could even survive being stuck permanently out of water like that (which is seriously implausible), would have evolved into an animal that was much more suited for living on arctic ice and not swimming rather than retaining their aquatic adaptations.
* ''Literature/TheHungerGames'': In ''Mockingjay'', Katniss sees Peeta planting evening primrose and the only part she registers at first is rose. Fortunately the thorny roses Snow leaves and primrose are not even mildly similar to look at, so she realizes her mistake pretty quickly. Mistaking one for the other would be more or less impossible.
* Played straight and averted in Creator/ChristopherPaolini's ''Literature/InheritanceCycle''. At one point, the BigBad sends [[ImplacableMan soldiers who are immune to pain]]. This seems to endow the soldiers with cockroach-like resilience, with them surviving hideous trauma and being able to move despite cut tendons and broken limbs. One takes dozens of arrows and still has to be beheaded. In reality, the injuries would kill them despite an immunity to pain. Averted in ''Inheritance'', where the irradiated Vroengard is full of mutants, suggesting Hollywood nuclear physics, but it is, in fact, a magical effect. This might be a homage to the ''Discworld'' series, which also frequently draws parallels between magic and radiation.
* According to his backstory from ''Literature/JamesAndTheGiantPeach'', James Henry Trotter's parents were eaten alive by an [[RhinoRampage escaped zoo rhinoceros]]. In real life, rhinos are ''herbivores'' (they are the largest extant perissodactyls, i.e. related to horses). Fortunately, the film adaptation averted this by changing said rhino from an actual rhinoceros to a large rhinoceros-shaped demon made entirely out of thunderclouds.
* ''Literature/LandInTheStars'': Used frequently:

* The Douglas Preston/Lincoln Child novel ''Mount Dragon'' has a transgenic strain of influenza virus called "X-FLU". It was designed to be a relatively harmless strain of flu that makes anyone infected immune to ''all'' forms of flu. Problem is, it kills everyone because [[spoiler:the revolutionary new method used to purify it damages the capsid]]. This should only affect the first generation of the virus, which certainly shouldn't cause lethal brain swelling on its own. All progeny virions would be produced from the viral RNA [[spoiler:and left unpurified]], making them more or less what they were designed to be.
* In ''Literature/PrinceCaspian'', Reepicheep the talking mouse has lost his tail in battle, and he argues with Aslan over whether it needs to be regrown. Both of them seem to think a mouse's tail has no practical value and is of use only as a badge of honor or vanity, but the tails of mice and rats are actually important thermoregulatory structures, without which he'd be quite vulnerable to heat stroke. (This is touched on in the movie adaptation: "Well, it's not just the honor. It's also good for balance, and climbing...")
* In ''[[Literature/RendezvousWithRama Gardens of Rama]]'', the refugees from the New Eden colony find another alien colony raising fields of corn, fruit, and vegetables in the total dark of Rama... by having giant fireflies fly over and illuminate them. Clark may be an astronomer to the bone, but even elementary physics would tell him the energy economy can't work.
* ''[[Literature/WingsOfFire Moon Rising]]'' has an in-universe example. The dragonet Winter is perplexed by his pet's refusal to eat meat, saying that if he's hungry enough, he should eat anything. He doesn't realize that some animals cannot digest meat at all.

* In the ''Literature/{{Replica}}'' series of YA novels, the bad guys repeatedly try to get hold of Amy's super-DNA by ''cutting her hair and fingernails''. The installment where her DNA reverted to "normal" after getting her ears pierced... wait, what?

** In "The Creeping Man", the eponymous character "devolves" into an ape by shooting up with monkey blood, or brain juice, or something. Just... no. (An episode of ''Mystery'' based on this story had to put a disclaimer at the beginning of it explaining this fact, lest the audience treats the story's events as pure {{narm}}. It is instead claimed that the character has been driven mad by the adverse effects of the hormones so that he ''thinks'' he is a monkey.)

* Creator/MichaelCrichton's novel ''Literature/{{Sphere}}'' has quite a few. The squid might get a pass for being an alien manifestation, although the biologist should know better than to believe that a normal squid could tear a metal structure to pieces. More flagrantly and not given a pass by the RuleOfCool, same biologist sees a seasnake and finds it perfectly normal to see one 1,000 ft down in near total darkness, AND makes a completely ludicrous evolutionary argument that marine organisms have more potent venoms because it's had longer to evolve (implying that land life arose separately rather than as an extension of marine life?). The whole discussion can be eliminated from the book with no negative impact yet it stands as a short AuthorTract.

* In ''Literature/SalemsLot'' Dr. Cody, who is not depicted as an ignorant quack but an at least semi-competent professional, says, "Why should your head hurt? Your brain doesn't have any nerves." First off, if your brain had no nerves then it would functionally be useless. He means that your brain doesn't have ''nociceptors'', which is true, but doctors universally knew very long before the book was written that there are all sorts of reasons why your head still hurts. For example, while the gray matter ''itself'' doesn't feel pain the blood vessels that run through the brain do. Ice cream headache is one example of this type: the sudden rush of cold to the head makes the vessels temporarily painfully retract. Also, sinuses can cause headaches, as can the inner scalp. Very often it's the back of the eyes (which are less round and go further back into the skull than they look from the outside) hurting due to eye strain or what not. The skull can feel pain too, but probably only if you've suffered serious cranial damage. No one with an M.D. wouldn't know all this.

* ''Literature/{{Seawalkers}}'': It's implied that Carag[[note]]who has the ability to turn into a cougar[[/note]] can't swim and Tiago mentions that this is a normal thing for a cat. In real life, both [[https://www.youtube.com/watch?v=VgnU-SMgf4M cats]] and [[https://www.youtube.com/watch?v=A3onuv3dMeE cougars]] are able to swim.
* One of the books in the ''ThroughWolfsEyes'' series by Jane Lindskold featured conjoined fraternal twins, a boy and girl who had been attached at the hand. This is completely impossible any way you look at it, as conjoined twins are the result of identical twins whose egg failed to split properly; fraternal twins, who are conceived from two different eggs, could never end up attached to each other. Furthermore, RealLife conjoined twins are ''never'' attached at the ends of their limbs, as the developmental error that causes imperfect separation of identical twins happens long before an embryo's limb buds appear.

** Meyer stated that the reason female vampires can't get pregnant is that when you become a vampire your body can't change. That goes for male and female... so how do they have sex? Male and females reproductive organs have to be able to 'change' in order to have sex and I doubt every single vampire was turned when they were having sex or aroused.
** Vampire venom at one point was stated to replace all fluids in the body which is why it turns into a sparkly rock-like substance. If you follow that logic, his semen should have been replaced. So the first time they had sex and he orgasmed... she should have become a vampire instead of becoming pregnant.

** The reason any species that engage in sex has a sex drive is to ensure reproduction. Vampires don't reproduce through such means, thus sex is meaningless to them and they would have no sex drive whatsoever. Which actually makes sense if combined with the bit about their bodies being unable to change -- they should neither be able to nor want to, have sex.
** Smeyer has made it known that she is oblivious to how the eye functions, and how she lacks any knowledge of the color spectrum. Bella sees rainbows around each source of light. We humans can experience the same using micro prism films, those glasses that make every light have a little image over them, or going around with the new 3D movie glasses. The only difference is that the glasses/prism film has a warning not to operate any machinery, drive, or go into direct sunlight wearing the glasses.
* In one John M. Ford short story, a research lab comes up with a drug called Argent 7 which gives the user superpowers. One user gives himself vision extending into the ultraviolet, by extending his retinas' sensitivity into that region. The problem with this is that human retinas are already naturally sensitive to UV -- what prevents us seeing in UV is that the cornea filters it out. (In RealLife, there have reportedly been experiments in which spy volunteers were given transplanted plastic corneas in order to be able to see into the ultraviolet.)
* In ''Literature/WorldWarZ'', the organ-smuggler claims that a transplanted heart from an infected donor would convey infection faster than an infected liver or kidney because it has "direct access" to the cardiovascular system. While the heart does propel blood, it doesn't ''interact'' with the vast majority of blood that moves through its chambers; the liver and kidneys, which constantly add and remove substances from the bloodstream, would probably spread a viral infection much quicker than the largely-impermeable lining of the heart's chambers.
* ''LightNovel/HeavyObject'': Major Frolaytia Capistrano has been using her military career partly as a way of hiding from her legion of suitors since women of her family are very likely to produce boys (making her attractive as a BabyFactory for [[HeirClubForMen nobles needing heirs]]). This is completely impossible: one of the most basic facts of human reproduction is that it's the ''male'' Y chromosome that determines biological sex (monosomy and trisomy syndromes notwithstanding); a woman can only provide an X chromosome.
* ''Literature/TheJungleBook'': ''The White Seal'' mentions Kotick getting attacked by a basking shark. Basking sharks are harmless filter-feeders.
* [[InvokedTrope Invoked]] in the fourth ''[[Literature/Magic20 Magic 2.0]]'' book, where Jeff is tasked with creating "lifelike" dragons for the other wizards to train against. His early prototypes are more show than substance since programming animal-like behavior is actually very difficult. Under pressure, he decides to go with a shortcut and copy the behavior of an existing animal as a baseline. He picks the most docile animal he can think of -- a sheep. So when dragons start spawning and attacking villagers, Jeff doesn't understand why that's the case, and why the most aggressive dragons seem to have horns all of a sudden (he never programmed those in). When he finally explains what he did to the other wizards, they point out that not all sheep are docile; rams can be pretty aggressive. Failing to understand their point, he claims that this is why he went with sheep, not rams. They have to resort to a "birds and bees" explanation to get him to finally realize that rams are male sheep.
* ''Literature/TheToughGuideToFantasyland'': Jones notes that the ecology of Fantasyland is very messed up as the result of there being very few bacteria, insects, birds or large herbivores since the "Management" it seems are ignorant about their importance. However, she believes the ecosystem is slowly righting itself so that humans will eventually be on the bottom of the food chain.
* ''Literature/TheCountOfMonteCristo'': The narrator states that the harsh conditions of living in a small prison cell for 20 years have given Dantes unusual vigor and physical strength. Of course, in reality, spending such a long time in unhealthy conditions and with little ability to exercise would have physically destroyed Dantes. Even all the digging on the second escape tunnel wouldn't have been enough on its own; regular calisthenics in his cell would have been necessary.
* The ''Literature/AnitaBlake'' Series is just chock full of biological artistic license-taking:
** It is stated repeatedly in the series that a lycanthrope's "beast" (that is, the animal they turn into during the full moon) can and does influence their behavior, attitudes, and so on. Unfortunately, the way most of the lycanthropes are portrayed makes it seem like Hamilton decided on a basic model (a "pack" led by an alpha male, with junior alphas and betas behind the senior alpha in authority) and just applied it slap-dash to every single type of lycanthrope in the series. She even did this to the weres that were based on animals that do not form "packs" or "herds" or "troops", but rather prefer to live singly or in pairs, only coming together to breed. She claims that this is a result of the lycanthropes' human sides messing things up, but this fails to explain lycanthropes preferring to gather in massive groups, being unusually power-obsessed and predatory toward their own kind.
** In some of the books it is stated that lycanthropes (especially, but not exclusively, the werewolves) avoid interacting with the police because the cops take issue with dominance fights that leave behind corpses. While this makes sense, it ignores the fact that most animal species whose males engage in dominance combat (including wolves and leopards, and hyenas, the three most common types of lycanthrope in the series) do so ritualistically rather than lethally. (For example, deer lock antlers to wrestle, leopards fight with sheathed claws, wolves nip rather than out right bite, and so on). Combat lethalities in such contests would thus be almost unheard of, with the winner of the fight getting to breed (with that female, that time around) and the loser having incentive to live to fight again (possibly somewhere else) rather than escalating to a fight to a death.
** Hamilton portrays the werewolves as living in a single polygynous pack. Actual wolves mostly mate for life and live in nuclear families.
** As noted above, leopards are solitary animals that do not form packs or prides. They generally come together in pairs only to breed or to fight for territory, and then separate to live singly again. Hamilton has them acting just like the wolves. She also does this with bears (another solitary species) and swans (a species that forms bonded pairs mated for life).
** Averted with the were-hyenas are portrayed by Hamilton as having a pack structure similar to the wolves, but matriarchal in nature, with a dominant female leading a group of beta females and submissive males. That's precisely how real hyena groups work. This is the only time she perfectly matches the social structure of the lycanthrope type to the the real life animal.
* ''Literature/TheEyeOfArgon'' features the victim of a GroinAttack "clutching his urinary gland". The author probably meant the bladder, but that's neither a gland nor the part that's injured in a groin kick.
* In ''Literature/JackBlank'', a [[ScaryDogmaticAliens Rüstov]] infection is regularly referred to as a "techno-virus", because a way of identifying it is by taking a blood sample and finding nanites in it. However, a Rüstov infection acts nothing like a virus: a Rüstov is a [[MechanicalLifeForms mechanical]] [[PuppeteerParasite parasite]] that attaches itself to a host body (of any multitude of species), and slowly [[TheCorruption transforms the host's body]] [[UnwillingRoboticisation into a heap of rusted, mechanical scrap]], and when the old body is spent they jump ship and find a new one. Nowhere near the behavior of a real virus.
* Spoofed in one ''Literature/{{Discworld}}'' novel: the Discworld's medical technology isn't advanced enough for the concept of viruses to exist, but this doesn't stop a doctor stumped for a diagnosis saying "it's probably a [[{{Malaproper}} walrus]]". The Igors, however, have managed to arrive at the concept of 'tiny invithible biting creatureth' and have developed ointments to kill them before they can infect wounds.
* In ''Babymouse: Beach Babe'', there was a moment where the titular [[FunnyAnimal mouse character's]] little brother has a VomitDiscretionShot after riding a carnival ride. In reality, rodents can't vomit.

* ''Literature/TheCountOfMonteCristo'': The narrator states that the harsh conditions of living in a small prison cell for 20 years have given Dantes unusual vigor and physical strength. Of course, in reality, spending such a long time in unhealthy conditions and with little ability to exercise would have physically destroyed Dantes.

* In the PointFantasy book ''Brog the Stoop'', it's mentioned that a female "Stoop" (vaguely elven creatures with blue skin) can only bear one "Stoopling," which would mean every generation is half the size of the previous one, thus leading to extinction pretty quickly.

* ''Literature/MaximumRide'' often has shades of this, particularly by abusing the LegoGenetics trope. Splicing bird DNA into human DNA isn't exactly easy, and trying to engineer a WingedHumanoid would be far more complicated than taking bird DNA for wings and putting them into a human zygote. There are no genes for bird wings that one can just take and put into another creature. It gets worse when the characters start developing superpowers, some of which were planned by the scientists and others of which mutated randomly. How would they even do that? There are also some little things, like hawks nesting in large groups and large sharks in less than 5-foot deep water, but genetics is the big one. This may be why in the Creator/MarvelComics adaptation, the Flock are cyborgs rather than bird-human hybrids.
* In ''[[Literature/TheMillenniumTrilogy The Girl Who Played With Fire]]'', Ronald Niedermann is a musclebound blond giant who has a disease that renders him unable to feel pain. The book even mentions that most people who have this disease die at a young age, but then handwaves it away by implying he's just too tough to die. This is not how it works. Normal life is dangerous enough for people with this affliction, but this character was an amateur boxer and gets in several fistfights over the course of the book. One untreated injury could conceivably kill him, most notably when he takes a full-strength punch to the kidneys from a pro boxer. But even before that, the kind of muscular frame he has cannot be maintained without weight training, which would be catastrophic without pain sensors to determine one's limits.
* The Douglas Preston/Lincoln Child novel ''Mount Dragon'' has a transgenic strain of influenza virus called "X-FLU." It was designed to be a relatively harmless strain of flu that makes anyone infected immune to ''all'' forms of flu. Problem is, it kills everyone because [[spoiler:the revolutionary new method used to purify it damages the capsid]]. This should only affect the first generation of the virus, which certainly shouldn't cause lethal brain swelling on its own. All progeny virions would be produced from the viral RNA [[spoiler:and left unpurified]], making them more or less what they were designed to be.

* In ''[[Literature/RendezvousWithRama Gardens of Rama]]'' the refugees from the New Eden colony find another alien colony raising fields of corn, fruit, and vegetables in the total dark of Rama... by having giant fireflies fly over and illuminate them. Clark may be an astronomer to the bone, but even elementary physics would tell him the energy economy can't work.

* ''Literature/{{Seawalkers}}'':It's implied that Carag[[note]]who has the ability to turn into a cougar[[/note]] can't swim and Tiago mentions that this is a normal thing for a cat. In real life, both [[https://www.youtube.com/watch?v=VgnU-SMgf4M cats]] and [[https://www.youtube.com/watch?v=A3onuv3dMeE cougars]] are able to swim.

** Considering the fact that sexual desire requires blood flow, there's no way vampires could have sex or sexual desire the way it's portrayed many times in the novels. Meyer says that venom serves the function of blood, but without a heartbeat? Not so much.

** Also, Vampires somehow gain two extra pairs of chromosomes after they change. Yeah.[[note]]They still can impregnate humans. And logically, gametes have 25 chromosomes, which with 23 of normal gamete makes 48. All human genes are in normal quantity and vampire genes seem to work in some range of quantity. One can infer that organism can function (better or worse) with zero, one or two copies of both vampire chromosomes, like with 1-n X, 0-n Y (all the X, XXX, XXXX, XXY, XYY... syndromes) or even 2-3 21 chromosomes (Down syndrome).[[/note]]

* In ''Literature/JackBlank'', a [[ScaryDogmaticAliens Rüstov]] infection is regularly referred to as a "techno-virus", because a way of identifying it is by taking a blood sample and finding nanites in it. However, a Rüstov infection acts nothing like a virus: A Rüstov is a [[MechanicalLifeForms mechanical]] [[PuppeteerParasite parasite]] that attaches itself to a host body (of any multitude of species), and slowly [[TheCorruption transforms the host's body]] [[UnwillingRoboticisation into a heap of rusted, mechanical scrap]], and when the old body is spent they jump ship and find a new one. Nowhere near the behavior of a real virus.