A peppered moth (Biston betularia)

Evolution today

Evolution is a slow process. It took fish millions, if not tens of millions of years to conquer the dry land. Perhaps, that’s why evolution is met with such resistance: it is hard to accept something that you cannot see. Magical computers – they work in front of us, magical rocket ships – they fly right out there. Magical evolution… hmmm, no.

Or, perhaps, yes?

Q: Where can I witness evolution today?
Lots of examples:

  1. Many pests develop immunity to toxins: bacteria adapts to antibiotics, rats – to rat poison, insects – to insecticides. In viruses, we can see insane rates of evolution. In AIDS, for example – that’s why it is so hard to smoke out: the viruses evolve literally in hours and adapt to any attempts on them.
  2. The average length of elephant tusks has halved in the last 150 years. The frequency of tusk-less individuals has increased. The reason is poaching. Greedy poachers mostly shoot the individuals with largest and nicest tusks.
  3. One of the most popular examples – the evolution of peppered moth. The original colouration of this one is greyish-white. It is effective in crypsis, when the moths lands on white tree trunks covered with lichen. However, as soon as large cities and factories appeared, the qty of melanistic black individuals has grown and outnumbered the original whitish colour morph. It happened because lichen does not survive with factories nearby, and tree trunk got covered in industrial ash, thus becoming dark. The original colouration became ineffective, and whitish moths fell prey to birds easily. While the black individuals strove. The species becomes darker and darker…

Паденица берёзовая - белая и чёрная

To some, the change in tusk length or colour might seem insignificant. But allow me to object:

  • Essentially, all animals are different from each other in small details. A mammoth is merely a woolly elephant. A giraffe is an antelope, only with long neck and long legs. A bear is just an overgrown, brown and plump wolf. Aren’t they? Entire biodiversity of Earth is built from the same model. A feather is an effective insulation and flight solution, that’s why all birds are using it. A plagiarism without remorse, but who cares: feathers work, and dinosaurs forgot to register a patent.
  • Any change starts with small. Since tusks could halve in size, they would halve once again. And again, till they’re gone. If they’re gone, the behavior of elephants will change: their mating rituals, defensive behaviour. In the end, they’ll become totally different beasts.

Q: Right. A beetle became the same beetle, just with a small stripe on its belly. Elephantie became the same elephantie, but with slightly smaller tusks. Small stuff. Show me some true evolution! A lizard becoming a snake, or a whale becoming a hippo. Something like that.

I was hoping you’d ask that!

For starters, an example of two different species: a wolf (Canis lupus) and a fox (Vulpes Vulpex). They are quite different in appearance, anatomy, physiology, behaviour. No-one would argue that they are different.

From vseskazki.su

From vseskazki.su

Now I am about to show you two animals that are even more different from each other:

Взято с Pixabay.com и Википедии.

From Pixabay.com and Wikipedia.

Those are two breeds of dogs: chihuahua and Caucasian shepherd dog. In terms of their behaviour, appearance and physiology, they’re not even a fox and a wolf. More like a… bear and a raccoon!

Взято с Pixabay.com

From Pixabay.com

But what’s most interesting about those two is that they have evolved from wolves literally in front of people! They are two dog breeds selected by people. There are hundreds of dog breeds so far, and the process never stops: people keep making new. Big, small, black, white – while all of them are descendants to an ordinary wolf, and we, humankind, witnessed them changing. Evolution in action.

The actual mechanisms are demonstrated. Dogs were selected by people based on their behaviour, intellect, looks. Those individuals that don’t meet our prerequisites were discarded, and eventually dogs became more like what we wanted them to be. It’s not even evolution, it’s pure logic. People figured the process out long before Darwin. “Discard the weak, and only strong remain, and those strong in turn give birth to strong offspring”. Evolution is an example of basic laws of nature: it doesn’t contradict anything and does not even introduce anything new. Everything changes in the world, everything can be selected. Animals are no exception. So what’s so fantastic about evolution?

It’s working. There, right in front of us!

Q: Dogs are one species.
Formally, yes. But it means nothing. Animal names and systematics are made up for convenience, and dogs are one species for the only reason: scientists want so. In biological taxonomy, it’s against agreement to give the status of separate species to artificially bred animals. Even if dogs are selected to the point where they start laying eggs, grow shells, fins and scales, they won’t become turtles. Formally, they’ll be turtle-like dog breed.

More detail on species and systematics – here.

Q: They’re one species because they can interbreed.

I don’t know for what purpose do scientists keep saying that over and over, but chihuahuas and Caucasian shepherd dogs don’t interbreed. Okay, their gametes are probably compatible… but gamete compatibility alone doesn’t make animals interbreedable. If so, then lions and tigers are one species, lots of colubrid snakes – too, wolves and coyotes, polar and brown bears. Even humans and chimps… there is a confirmation that human sperm can penetrate chimps’ ova. Thousands of species in the wild are separated from each other by factors other than gametes’ compatibility.

For animals to be interbreedable, a series of requirements must be met. Such as:

  1. Geographic (they must inhabit the same location).
  2. Anatomical (copulative organs must “fit” each other, the overall anatomy must allow for sex to happen)
  3. Behavioural (they must recognize each others’ mating rituals, let alone be attracted to each other).

And only after those, physiological and genetic factors come. Even if a single prerequisite is not met (say, animals live apart, like lions and tigers), they don’t interbreed. Now go and think: can a male shepherd dog have sex with a female chihuahua? Would it even come to their minds: I doubt that they embody each others’ ideals of attractiveness, and as for little chihuahua – it will probably be afraid of that huge woolly monster! Even if they decide to mate, how are they gonna do it? Will chihuahua even survive?

Okay, true, we could help them a little: collect semen and ova from them in a lab, and then – it’s technical business. But pardon me, help doesn’t count. Otherwise, we could let geneticists into the game: they’ll do some chromosome mojo, and suddenly, giraffes and hippos are one species…

Dog breeds are true speciation that happened right in front of us!


Further reads

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