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Whao! Reminds me of those black moths in the industrial revolution.

Is it possible this is just a coincidence? Has any other animals, or amphibians specifically, found to have higher melanin counts closer to Chernobyl?
Also, are these frogs considered melanistic or do they not have enough melanin for that?

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Here come the giant Rad-Toads. Fallout was right about everything.

Not an animal, but still interesting:

https://www.atlasobscura.com/articles/chernobyl-black-fungi-space

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email the author

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So... Melanin grants resistance to ionizing radiation?

Honestly the our timeline and the fallout timeline are starting to align too perfectly

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Except the bit where we have nuclear powered cars and ancient computer terminals.

every little bit helps when it comes to reflecting or diffusing electromagnetic radiation

How dare you bad mouth RobCo tech!

The study methods detailed in the scientific article were very interesting to read about.

https://onlinelibrary.wiley.com/doi/full/10.1111/eva.13476

I'm wondering why they only studied male frogs. Is there a pigment difference between males and females? Were males simply easier to find?

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I thought white color reflects all frequencies while black color absorbs all frequencies. Why does nature use black color then?

Different part of the electromagnetic spectrum I would assume. Not like we see radiation.

We invented transistors early on instead, can't happen.

Same reason the greater majority of stealth craft are all black. Sometimes its more about just redirecting radiation, rather than purely reflecting or absorbing.

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Hyla arborea are very difficult to sex visually, males and females are externally pretty identical when they're not inflating their vocal sac, either you very closely examine their inner forelimbs for nuptial pads or you wait for them to call. It says they collected reproductive males during breeding season so I guess they captured calling frogs.

While It’s true we can’t see ionizing radiation, we can see radiation, we call it “visible light.”

I'll point out that eumelanin and pheomelanin in high concentration are always dark colors. I don't think I've heard of any melanin derivatives that are white... if there were, you've got a good point that they might work even better.

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Is there a reason they call this evolution and not adaptation?

Ah, but you want it to absorb the light. This allows the energy to be dissipated as heat to surrounding tissue. An alternative is DNA absorbing the energy and breaking apart / being damaged.

This. In fact the melanin protects primarily the DNA and not the whole cell.

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There's a selective pressure for darker skinned frogs. This pressure means that the darker skins frogs are more likely to produce young. Over generations, this effect is compounded. Eventually, the dark frogs will far outnumber the lighter.

Think of it this way; a tan is adaptation. The ability to tan, coming about as a result of generations of sun exposure and resulting cancers, is evolution.

sigh

selection. it's not evolution.

Something confused me, "More than ten generations of frogs have passed since the accident and a classic, although very fast, process of natural selection may explain why these dark frogs are now the dominant type for the species within the Chernobyl Exclusion Zone."

What does this mean since the accident was in 1986 and frogs breed annually. How long is a frog generations?

Gamma radiation, the form of ionising radiation that's an electromagnetic wave, is so small it doesn't really reflect off things, it'll pass straight through a mirror for instance, or y'know, a thin sheet of lead. Better to block it by giving it something harmless that can intercept it and get ionised that's not DNA. Though in this case it appears that it's more that melanin can mop up free radicals and reduce DNA damage that way. Basically, you can't realistically block gamma radiation with frog skin, but you can stuff it full of compounds that mop up the damaging byproduct of being hit with it.

Males are easier to find - they sampled them by basically going out at night in the breeding season and locating them by sound, likely the easiest and most efficient way to quickly find sufficient frogs for study.

>In total, we examined 189 H. orientalis adult males, captured during active calling from 10 PM to 1 AM.

I can't think of any protective quality melanin would have from ionizing radiation. It is more likely that some other protective trait is adjacent to the genes causing darker frogs or that a mutation causing darker frogs was triggered by the radiation and happens to be advantageous locally. (Nuclear engineer with minor in health physics and biology). However, I would be open to be corrected.

From the scientific article:

>Females start to breed at 2–3 years of age (Özdemir et al., 2012), which means that 10–15 generations have passed since the Chornobyl accident.

2022-1986=36 years

Divide by 2.5, which is the approximate number of years it takes for a newborn female to reach maturity = about 15 generations of new reproductive females.

Thank you! That is surprising, I didn't realize how long lived and slow breeders they are.

Huh? Evolution is a non-random selection process - with selection *by giving some increased chance to breed through an inherited trait

Edit *missing words

Yup. Frogs are easy to find by sound. Not so easy by sight.

You need to look up the definition of evolution bruh

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in HS i saw the grey moth in England, soot, turned black article. was told it was evolution, just as you learned. years later I did my science degree and discovered that this was a lie, it's selection not evolution

years later I find myself in a HS teaching biology. today it's that same moth, evolution. "you guys realise that this isn't evolution, it's selection, right?" this is the way we're going to teach it.

you are a product of this.

it's not evolution, it's merely selection and variance. two things needed for evolution to occur, this isn't evolution.

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selection process. yes. this is an example of selection process. not evolution.

I would love for you to explain what you think evolution is, if it’s not this.

Evolution is the change in heritable characteristics over generations. That is what’s being documented here. It’s micro evolution, but it’s evolution. Selection is ONE pressure causing evolution. The selection is the increased radiation environment around Chernobyl that favors individuals with more melanin. But the higher proportion of individuals with increased melanin in the population over time? That’s evolution bruh.

there's no such a thing as micro evolution. what you're referring to is called selection

Selection is the pressure. Evolution is the result. You have a bad understanding of the terms and hopefully are not passing this bad understanding to your pupils. Read what people with PhDs in evolutionary biology have to say on the matter.

What’s an example of evolution based on your understanding?

The molecules that make up most white things usually aren't able to screen (what a metal does) or significantly absorb light with energies high enough to be damaging to DNA. What you see as white is usually only good at scattering most might in a relatively narrow band of visible light, and since scattering doesn't change the angle of the main energy path much, it's not really protective (you'll get a chain of scattering off of lots of molecules as the photon dumps energy into them, including damaging the DNA).

Similarly, absorbing light is difficult as the higher frequencies require electronic and eventually nuclear transitions (this is the difference between x-rays and gamma rays) to actually absorb the photon. So scattering is the predominant energy absorption mechanism for biological interaction with gamma and x-rays.

Evolution writ large requires the production of new genetic information in the living population. This is simply natural selection of traits that already existed in the population, not the complete cycle. Unless I'm reading the article wrong.

incorrect. selection can be a result of it's own. evolution is something much greater than simply changing colours. you're still confusing selection (and variance) with something greater, so much greater that it completely overshadows selection. these frogs are the same frog in a new colour. where as a cat and a tiger are not on the same level of disparity.

if my mums pink roses turn white it's not an evolution of the rose. they are still roses, with a new colour. that's selection, as a pressure, yes; and variance IN POPULATION as a RESULT. there's no evolution.

UV light is a form of ionizing radiation. That’s why melanin is a thing.

Not sure how effective it is against radioactive radiation.

We can see a very small sliver of radiation. Actually, radiation is the only thing we see.

Not really though all that you mentioned fits with adaptation

JFC. You are a science teacher? Where? Do you deny the fact of Darwinian evolution?

It’s not JUST a change in color. You’re acting like the frogs got a sun tan. What is changing over successive generations is the frequency of genes in the population that code for more melanin. The population is changing. The gene frequencies are changing. The offspring are very slightly different than their ancestors, on average. That’s evolution, baby. The author of the study has a PhD in biology.

you're describing selection and variance. this isn't a new frog species, it's a new colour.

You really should take a hard look at whatever “lesson” you got in college and actually read what evolution means from some current evolutionary biology papers. It doesn’t only refer to speciation. Obviously speciation can happen as a gradual process without a clear start and end date as two populations slowly diverge. That process is called…evolution.

What's the length of a generation in this species? Do they grow to maturity in a year?

>Melanin is responsible for the dark colour of many organisms ... And its protective role can extend to ionising radiation too

Interesting, can we produce melanin externally and use it as shielding, in lets say spaceships for example, against space radiation?

This is way off topic, but...

For spacecraft operation longterm in a void, heat dissipation is a serious logistical issue. Engines, circuitry, etc, generate heat that builds up without any atmospheric particles to transfer it to. Surfaces that absorb energy directly from sunlight can get too hot. For this reason, NASA's designs specifically called for white exterior surfaces on their shuttles.

More detail about that here:

Spacecraft Subsystems Part 3 ‒ Fundamentals of Thermal Control (PDF)

>Thermal control surfaces can be any surface that is used for spacecraft thermal control to include coatings, paints, and finishes. Most internal and external spacecraft components have a thermal control surface to help control its emittance and/or absorptance properties. The performance of these surfaces are characterized by the ratio of absorptivity to emissivity, α / ε, which are characteristics of heat transfer by radiation. For example, white paint has a low ratio and therefore is used as a heat emitter. Ratios greater than 1.0, like blank paint, will get hot when exposed to sunlight.

>Black and white paints are the most common color. Most paints have a high emittance, with varying absorptance and electrical conductivity properties. Black paints have the following characteristic: α ≈ ε ≈ 1.0, which is close to thermal equilibrium. This means that most of the heat that is absorbed is then emitted. This makes black paint an effectively neutral color, thermally. Because of this and its performance ratio of >1.0 as previously discussed, most internal spacecraft components are painted black. Most external spacecraft surfaces are painted white to minimize solar energy absorptance.

>Thermal control surfaces are also a key part of other thermal control methods to be described in this section, which include multi-layer insulation (MLI) blankets and radiators. Aluminized Kapton is commonly used for the MLI blanket external layer. Surfaces with a performance ratio of less than 0.4, like white paints or optical solar reflectors (OSRs), make them effective radiators.

I can’t wait for these show up in Stalker 2

Interesting, I was thinking that melanin provided protection by some additional properties than just being black, maybe by some organic property, I was probably mistaken