We live in an unusual world. Science is finally willing to admit that man mated with may other variety of humans that were not homo sapiens, such as Neanderthal, Denisovan and an, as of yet, unknown other of the homo genus.
Some distant relative animals can mate and produce offspring, such as horses and donkeys creating mules or lions and tigers creating ligers, but there are some animals that do not successfully mate between them with offspring (at least none that science has yet identified openly).
Chimeras aside, mutations from toxic circumstances are something of concern. I grew up in the 70s when there was talk of pollution, ozone, Three-Mile Island, mercury in the fish in our Chesapeake Bay, companies polluting streams, as well as banning of DDT.
Today, we face pandemics from close populations with animals, Fukishima, Chernobyl, Monsanto and others all contributing to a great unknown for human population's reproduction.
At some point, we reach a tipping point between overpopulation, lack of resources, religious wars, famines, drought, infertility, and potential mutations. In fact, mankind's death will most likely not come from bombs or asteroids, but by slow attrition due to producing plastics and chemicals, crops dowsed in chemicals and the like.
Our only hope truly is in us mutating, adapting.
Some say alien greys are us in the future, having handled a radiation-filled world and little labor, but much brain focus. Their eyes would be huge because there is darkness from constant volcanic activity....
With the fear for our world's precious resources and our toxic intervention, it's no wonder that movies like "Prophecy," "Food of the Gods," and "Day of the Animals" were born in the decade of the 1970s when we really began to see the limits of our world's resources.
Mutations can occur for many reasons, as in the whole process of cell division to create life, something can go wrong. Some are created by exposure to drugs during pregnancy, like thalidomide once given out in the 1950s and 1960s for morning sickness that caused defects in the limbs of the children born.
In the case of frogs, they can be a good indicator of pollution issues in waterways because their legs will grow oddly because they are affected by pollution in the delicate larval stage when limb buds are forming.
Sometimes, a mutation is an odd throwback gene from somewhere in the heritage, like hypertrichosis (wolf man syndrome)
This baby (below) born in Nepal died soon after of neural defects associated with anencephaly.
Polydactyly is a common mutation - extra digits on hands and feet.
Chernobyl meltdown showed us a longer time-line of what can occur to animals and to humans. The human deformities and mutations were dramatic and tragic. There is only time before Fukishima produces the same results as this frog, as well as humans.
Our best fictional mutants came from the 1950s Sci Fi genre and 1970s ecology-fearful movies -
"Teenage Mutant Ninja Turtles"
"The Toxic Avenger"
"This Island Earth"
"They Came From Outer Space"
"The Incredible Shrinking Man"
Here's some of my meme's on the subject-
- Awesome mutant and monster movies -
The Terror Within (mutant) Postapocalyptic baby
Prophecy (mutants) Mutants in the polluted forest
Food of the Gods (mutants) Giant people-killing rats
The Funhouse (mutant) A mutant killer at the carnival
Hellboy (mutant) A demon who means well
Them! (mutant) Enormous city-attacking ants
King Kong (mutant) Enormous city-attacking ape
Gremlins (mutant) Little furry guys who can turn into something evil and nasty
28 Days Later (mutants) Zombies born from a virus
Cloverfield (monster) Giant city-attacking monster
The Descent (monster) Cave humanoid
Trollhunter (monster) Giant trolls in Norway
Pitch Black (monster) Flying monsters on another planet
The Host (monster) Giant city-attacking monster
Don't Be Afraid of the Dark (monster) Tiny monsters attacking humans
Jeepers Creepers (monster) Humanoid monster serial killer
King Kong (monster) Giant city-attacking monster