Survival of the Fittest?

I bloody hate Cockroaches. I tense up when I see them on TV, I shriek like a little girl if I see one in real life, I even started vomiting when a "friend" threw one at me in Florida once. I have Katsaridaphobia. Phobias are usually triggered by an event that stores a little piece of information in the brain's hippocampus that is filed away under 'DANGER'. Thus when the situation is encountered again the 'DANGER' file pops open and invokes the fight or flight mechanism, in most phobic situations it will be flight. I realise cockroaches pose very little danger to me but I'm still terrified of them

I remember the event that caused my phobia. I was reading Better Than Life by Rob Grant & Doug Naylor, in the book it was a massive amount of time in the future and Planet Earth was ruled by 'eight foot long cockroaches'. I only had a sneaking suspicion at that point that cockroaches would one day inherit the earth but after reading BTL it was confirmed and my phobia was properly realised. Cockroaches will eventually take over the planet, they have to, it's only matter of time because they've been trying so damn hard, they'll work it out eventually, evolutionary theories suggest in their favour. They're just biding their time. This is in my favour though, I will be long gone by the time it happens. Cockroaches don't have very good memories and they always turn right, both factors equal a very slow evolutionary progression surely. A bunch of bored and over-funded scientists experimenting on cockroaches in their lab of insect torture discovered that its very hard to condition cockroaches. If a cockroach in a Y-shaped tube turn right at a crossroads one of the little blighters antenna's got snipped off and back to the start of the maze it went. 57% of the antenna-less cockroaches turned right again. The scientists, showing their humane side left the remaining antenna intact.

Cockroach fossils have been found from 354–295 million ago. They survived whatever it was that killed the dinosaurs. I thought dinosaurs were hard bastards but they've been shown up by this little shit. They have some amazing survival traits but probably wouldn't, as is popularly believed, survive a nuclear war. They certainly wouldn't survive a nuclear explosion, they'd be vaporized like everything else. It's true that cockroaches do have a much higher tolerance to radiation than humans. They can take up to 15 times the amount of radiation that would kill a human. 

I don't believe that nuclear armageddon will be the end for us and it certainly won't be the reason cockroaches will take charge. A cockroach can survive without food for a month. The mythbusters failed in their attempt to drown cockroaches: I know that wasn't the premise of the experiment but I hate them, the little arses. 

However, the most (I've gotta give it to them) impressive survival capability of the cockroach is their uncanny ability to survive having been decapitated for up to three weeks. Cockroaches have a much much lower blood pressure than humans do.The sliced surface would clot rapidly leaving no time for uncontrolled bleeding. You may ask "How can the wee fucker survive without its brain?". Well, the cockroach's respiratory system is made up of spiracles rather than a nose or mouth for inhaling/exhaling. The spiracles pipe air directly to the tissue through a set of tubes call tracheae. The brain does not control these and the blood does not carry oxygen around the body. "But still, it's not living so to speak...?". As with most insects, cockroaches have nerve tissue agglomerations, or ganglia, in each segment of the body. Again, these are not controlled by the brain so a cockroach with no head can still manage very simple physical functions, standing, reacting to touch and movement.

Sickeningly a cockroach head that has been removed from its body can survive for several hours until it runs out of steam. Experiments have been conducted showing that if given nutrients and is refrigerated the roach head can last even longer. Like a sick little tamogotchi.

If you want to rid yourself of a cockroach you can't drown it, you can't expose it to radiation, you can't starve it, you can't chop it's head off. Stamp on it. Stamp on it good. Scrape it up of the floor, gather the resulting substance into a pile, fold it into some paper, stamp on it again, fry it, blend it, bin it, empty the bin, put in compactor, crush the compactor, bury compactor, blow up the planet.

For a long time I thought that cockroaches were the hardiest species on the planet. That is until I learnt of the cute sounding Water Bear.

Yeah, that picture is not a picture of a Water Bear.

The Water Bear or Moss Piglet is not cute. It actually looks fairly disgusting. You're unlikely to have ever seen one though as the biggest Water Bear probably wouldn't grow over 1.2mm. Newly hatched larvae could be smaller than 0.05mm.

Tardus - Slow. Gradu - Step. Tardigrades or Slow Walkers might well have had their name taken from Dr Who's TARDIS.Time And Relative Dimensions In Space. Tardigrades have an astonishing ability to suspend themselves in any given moment only to reanimate at a later, some times at a much much later point in time. This process is called Cryptobiosis. The Tardigrades metabolism drops to less than 0.01% of normal and their water content to roughly 1% of normal. The water is replaced by a type of sugar called Trehalose. This sugar is also found in sea-monkeys. 

Tardigrades effectively dry themselves out in a process called desiccation and it is just about the most fail safe defence mechanism imaginable. The Tardigrade will do this to itself when it's environment becomes inhabitable and can longer provide for it's needs. Very little can affect the Tardigrade when it is in this state. One deep sea species can survive 6000 atmospheres of pressure. 10 metres under the sea exerts about 2 atmospheres of pressure. A Tardigrade can survive for a couple of minutes at -272°C which is basically absolute zero. They can go the other way too, surviving temperatures of 151°C. Like the cockroach they can survive blasts of radiation. Only they do it much better than a cockroach. They can survive 5000Gy (gamma rays). 5-10Gy would kill a human. They can survive droughts with ease, 120 year old Tardigrades have been found in their suspended state. 

 In 2008 a group of European scientists exposed two species of Tardigrades to the vacuum and had radiation of space. They survived the vacuum and low temperatures easily, and even laid fertile eggs afterwards, but exposure to the full intensity of the sun's ultra-violet radiation caused them problems and survival rates were then much lower. But still, a handful survived the full frickin' force of the sun's power! All that it takes to bring these lil buggers back to life is a drop of water and they'll be on their way.

I'm not afraid of Water Bears though. I probably would be if they were eight foot long but I'm so totally full of admiration for the way that they exist. They will be on this planet long after humans have wrecked it all or humans can no longer exist under the expanding sun. I have got absolutely no idea how you could rid yourself of a Tardigrade if you found yourself in a situation where you wanted to. I'd hazard a guess that you'd have to take him by surprise attack with a flat swatting weapon because once he dessicates he's there for a while.