Naked Science Forum
Life Sciences => Plant Sciences, Zoology & Evolution => Topic started by: neilep on 12/07/2008 13:33:23
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Dear Cockroacheologists !
See Elphabeth here ?
AmericanCockroach1.jpg (28.83 kB . 250x332 - viewed 4796 times)
She's a fine specimen of Roach goodness !.....in the Roach world she's a supermodel and won't get out of bed for anything less than three leaves and some animal protein and perhaps a nice drain to dwell under for a while !
I've often heard that cockroaches are resistant (or more resistant) to radiation than ewe and me.....is this a fallacy ?...if not.....then what makes them so hardy against radiation nastiness ?
Thank ewe
Neil
Rogue Roach Asker
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Hi Neil
They're not! It's a myth! They say cockroches would be the last survivors on earth, but that's only due to them being able to consume a very wide variety of products.
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Having an exoskeleton may allow them to survive a higher dose of radiation than us mammals,
analogous to a person wearing a suit of armour being able to withstand higher levels of radiation.
Dr Karl on cockroaches and radiation...
Drs. Ross and Cochran found that a dose as low as 6.400 rads would kill 93% of immature German cockroaches - making cockroaches only six to fifteen times tougher than we frail humans. Sure, cockroaches survive radiation better than we do - but they curl up and die at doses than don't even bother other insects.
http://www.abc.net.au/science/k2/moments/s1567313.htm
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I rather suspect that the reason she won't get out of bed is because she's pinned to it.
Mythbusters did a prog on this topic - they found that cockroaches weren't especially good at resisting radiation - they tested a few different creepy-crawlies and found one of the others was much more resistant than the roaches - sorry can't remember exactly what they were though.
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To understand this you need to understand why radiation is dangerous.
Radiation damages DNA. DNA are the instructions to build new cells and perform cell functions. So damaged DNA is a primary concern when it needs to be used to replicate another cell.
Imagine DNA as like construction directions for a tv. You don't really need them to operate the tv. But you can't build a new tv without them. So DNA in a cell could be damaged beyond repair but the cell will continue to function effectively until it tries to replicate. That's when it realizes the DNA is damaged and the cell commits sudoku.
Cells that replicate often are more likely to die from exposure to radiation than cells that don't replicate often. That's why cancer patients lose their hair. The skin, intenstines, bone marrow and other organs are more susceptible. The brain, cortical bone and nerve cells are more resiliant.
The exoskeleton of a cockroach only replicates when molting. When it's done the shell becomes hard and replication stops so it's more resilient to radiation.
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Where did this myth come from? Anyone know?