Amazing evolution #1 – Convergence

last month
57 in science

Welcome to the first of a three-part (or more) series about the wonderful world of evolution

I will cover at least three topics without being patronising and going back to basics:

  • Convergent evolution
  • Unintelligent design
  • Artificial evolution

Evolution is one of the most elegant theories ever conjured up, alongside other classics such as F=ma and E=mc^2. Everything from all fields of science, be it biology, genetics, geology or even physics, simply fits in place like a jigsaw piece. Every time. Without fail.

But it seems to get a bad rap anyway. Not everybody believes Darwin like they do Newton and Einstein, and many think evolution is simply SO beautiful that a higher power simply created it all.

Well, yes, it’s often beautiful. I mean, who doesn’t like the occasional tape worm chomping away in their gut?


But to me and millions around the world, the long and arduous journey over billions of years through time and death is far more beautiful and fantastical than a snap of fingers.

I want to show people the limitless nature of nature, and how remarkable it can truly be. Put away your preconceptions of belief, disgust and cute mammalian bias, and let’s dig in.

Convergent Evolution

First I will explain how this works, and then I’ll jump into some awesome and sometimes bewildering examples of what is basically glorified coincidence.

Convergent evolution is an evolutionary process in which two or more species develop similar or identical traits, despite not being closely related genetically or geographically. This process demonstrates how nature will find the same solution for similar problems across the world, and can be found in thousands of examples in the natural world.

Flying

Sometimes, life has a good idea, say, wings. But life is not a single entity handing out good ideas to those who deserve it. Life did not give butterflies wings, and then, after hours of begging, finally handed them over to bats. No, these were totally separate good ideas that came about from the same initial ingredients. Birds, bats, MQ-9 Reaper drones, they all came to the same solution through entirely unique processes.

Birds

There are about 10,000 species of birds that we so far know of, and they come in boring form or splendorous form.


a boring mockingbird


A Splendiferous Greater Bird of Paradise!

But if evolution is so true, what use is half a wing? Surely there was a point between the time when there wasn’t a wing and when there was a wing?

Well, yes. According to science, feathers, as well as human hair, evolved from reptile scales. All three are formed from the same part of the embryo of each animal group. They all develop from something called ‘placodes’ – patches of thickened skin.

A dinosaur who developed the mutation of lighter scales and later feathers may benefit from insulation, keeping eggs warm and would also exploit the properties of feathers for aerodynamic escapes, higher jumps or even becoming more virtuoso tree climbers. I’m thinking chickens. Chickens can’t fly but they make good use of those feathers nonetheless.

With escape in mind, you can easily imagine the steady process from higher jumps, leaping from tree to tree before eventually lifting off entirely.

Bats

Bats are not birds, they’re mammals. There are about 5,500 species of mammals. A bat's rise to Batman-like abilities came through a different process via mammalian genes. Compare a bird wing to a bat wing:

Nice picture. The most striking thing here is that a bat wing appears to be more finger than anything else, put together with skin like my old school friend’s webbed feet. The bird’s skeleton, on the other hand, made the hand stubbier and extended the actual arm. A bat’s wing is essentially a giant hand.

Insects

Insects are not bats or birds, they’re invertebrates. There are around 1 million types of insects. As we learn in primary school, bugs don’t have skeletons in the way we do, so there’s no skeletal x-rays to be seen. This, combined with the fact that insects don’t fossilize very well makes it very difficult to actually find evidence of the process of acquiring flight.


oh, wait, here's an insect x-ray

There are theories though, generally looking at how they were developed from insect appendages for balance, hopping around on water and so on. The strongest evidence suggests development from abdominal tracheal gills or similar, as can be seen in this lovely shrimp-like machilis.


Thank you, Wigglesworth

Here’s the cute version:

Others

So here we have three distinct processes in which flight has formed. But there are several other examples of animals that seem to be in that very transitional phase, like the ridiculously adorable flying squirrel, which actually glides steadily.

The flying fish, which has been caught on camera flying for a full 45 seconds

Frogs, lemurs, even snakes and lizards are working on taking to the skies!

What we can see is that even distant relatives simply re-use the genetic components provided in our DNA, shuffling them around to better adapt to the environment. There is no new material in a bat's skeleton or a human or bird skeleton. It’s all just re-proportioned.

Swimming

Fish swim. Fish live in water. Dogs can also swim but they usually don’t live in water, because dogs are mammals. Dolphins and whales are mammals too, so why do they live in the sea?

This is a pretty wild evolutionary U-turn which made sea creatures crawl up to land, realize it ain’t all that, and then hop back into the sea where it’s cool and less smoky.

Whales harbour the same skeleton we humans do, reformed to hold bigger, better lungs and a bigger heart. They even have tiny, vestigial legs deep beneath the blubber, and hair across their whole body – at least as babies.


A whale before it made the leap into water… I guess

Dolphins are wonderful examples of convergent evolution so drastic that they can easily be mistaken for sharks to the untrained eye, a fish millions of years separated from mammals entirely. This is why a dolphin’s tail is horizontal compared to the shark and fish’s vertical tail – They were separate inventions.

Additionally, there are multiple types of river dolphins that survive in fresh water, all of which evolved separately across the world in China, India and the Amazon.

Walking…or not

This is not a snake. It’s a legless lizard. Get your head around that one.

Seeing

Eyes are the most amazing and intricate little balls of jelly I can currently think of. Eyes are commonly used to argue the existence of God, but a closer look and you see there’s nothing really unique about the process that eyes took to go from ‘no eye’ to ‘eye’.

And this is so true, that eyes also evolved multiple times.

Humans and squids, for example creepily evolved the same eyes using the same genes, separately. In fact, the most recent ancestor of human and squid died out over 500 million years ago.


Actual squid eye

Compound eyes in insects and crustaceans are another example of a solution to blindness. In fact, the mantis shrimp’s eyes are capable of seeing much more than we can. Where we have 3 photoreceptors to pick up red, green and blue light, this shrimp has up to 16 receptors, 6 of which can see into the Ultra-violet range.

...Such a shame their brains aren’t big enough to discriminate between colours anywhere near as good as us, but hey, nice try.

Eyes have formed in their own way at least six times, from the camera eyes of octopuses and humans to the mirror eyes, cup eyes, pinhole eyes and compound eyes of… other… freaks.

Camouflage

Camouflage Is a necessity for so, so many animals. It’s no surprise that many animals mimic other animals sharing the same environment. If your neighbor never gets any shit because he’s bald with tattoos and a gun, but you can’t afford that kind of protection on your salary, the cheaper solution is just as effective; shave your head, fake tattoo stickers and a water pistol should suffice.

The same thing goes in the animal kingdom, where plants often mimic each other to ward off threats or, more strangely, attract customers. Sexually.


To a bee, this is a pretty legit mate

But a plant mimicking a plant, or an animal mimicking another animal for the benefit of itself is not convergent evolution. These things happen as a response to external stimuli.

It’s much stranger and more fascinating when you see a whole range of frogs evolve the same appearance around the world, having had no internet to exchange ideas at the time. They all found the same solution to hide from predators and blend into the background.

Hearing

We like to hear with our ears. It works pretty well. Echolocation is something else entirely. I mean, it’s not really, it’s a kind of hearing, but a skill we lack, nonetheless (aside from that one blind kid).

Bats and Dolphins both evolved this separately. Scientists in London revealed that ‘200 sets of genes had been identically mutated in dolphins and bats’. The bizarre thing is that not all of those genes were for echolocation. Some were actually linked to vision. Bats that do not use echolocation lack all of these shared genes entirely.

Intelligence

We normally like to think of intelligence as Us vs. Them in the natural world. We are super smart; they are pretty dumb. Apes are kinda smart I guess, but only because they’re trying to be like us, if Jungle Book taught me anything.

But intelligence comes in many different forms, and the intelligence of some birds expresses that wonderfully.

Crows are considered one of the most intelligent animals out there. They can adapt easily to human intervention, learn tool use quickly and effectively and even show their own ingenuity without training.


Crows have noticeably bigger brains than other birds. In terms of proportion, they are the same as Chimpanzees

Some crows in Japan have been spotted carrying nuts high up to a lamp post, dropping the nuts down to the road below for cars to crush, waiting for traffic lights to turn red and enjoying the easymeal in safety.

Despite having a totally different brain structure, the mental tools shared among primates, dolphins and crows – anticipation and natural reasoning – is otherwise identical. Almost no other animals in nature share these problem solving traits. Other intelligent birds are known to hold grudges – remember specific birds that stole food or annoyed them in some other way, and punishing them later by not providing food sources, for example.

So there you have it, the wonderful world of convergent evolution. I mean, this was barely a scratch on the surface. Just a brief look at the Wikipedia list will make your mind spin with apathy.


…and then some

But I have a habit of writing too much, so hopefully this will inspire people to go on that wiki page and take a look and learn the wonders of how leaves have evolved multiple times, pitcher plants learnt to trap animals the same way, swim bladders evolved in fish and octopuses, different orb-weaving spiders evolved, migrating birds and dolphins have half their brain sleep with the other half awake, some snakes share the same camouflage, opposable thumbs are found in primates, bears and opossums; fingerprints in humans and koalas, prehensile – controllable - tails in mice and monk… Ok I’m done.


High five

Sources:


https://www.factmonster.com/science/animals/estimated-number-animal-and-plant-species-earth
http://assets.nydailynews.com
https://bekkabrodie.com/2014/08/08/insect-flight/
https://askabiologist.asu.edu/human-bird-and-bat-bone-comparison
http://ngm.nationalgeographic.com/2016/02/evolution-of-eyes-text
https://en.wikipedia.org/wiki/List_of_examples_of_convergent_evolution
https://en.wikipedia.org/wiki/Convergent_evolution
http://changelog.ca/quote/2011/10/30/eyes_evolved_multiple_times_but_have_common_origin

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41
  ·  last month

Awesome. Informative and interesting without blinding us with the science [I actually wanted more science but that's just me].
Keep it up!

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57
  ·  last month

Cheers! Yeah I really wanted to be more scientific but I'm also told too long is boring so I had to think about it differently... Maybe if I ever gain more popularity I can build on the science aspect more =D

38
  ·  last month

That's a great, thorough explanation of evolution, with nice pictures. I'm always interested in evolution and I just posted a photo of marine iguanas on the Galápagos islands: A superb place to understand and see evolution.

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57
  ·  last month

Thanks, glad you enjoyed it. Yeah It's been a dream of mine since I was a kid to go to Galapagos and get chased by giant tortoises

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38
  ·  last month

Haha, then you should be a great runner!

54
  ·  9 days ago

Your posts are so good I don't get why pay is so low. The Dark Ages I guess before HF19 and new and improved articles about jerk mammals and rapey dolphins.

Damn, I envy good writers like u. I have no writing skills, pretty piss poor actually. Great posts!!

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57
  ·  9 days ago

Haha I super appreciate you going through them all! Always nice when my stuff is recognised even by a single individual.

Like reality, it's who you know, rather than what you can do, for the most part. I had a period of high earning having become friends with a small whale, but he has largely been absent the last few weeks so yeah, my recent stuff is barely making a dime. Ah well, I enjoy doing it anyway.

So I see you're an artist. Visual or only musical? I'm looking at two projects collaborating with artists if you wanna split the $0.25 between us, and you could re-post on your page if you wanted, too.

I've already got a few artists lined up but need more!