My wife and I were watching a Discovery Channel Programme on animal camouflage, and we both began to wonder…How’d they do that!?
Specifically, how does evolution choose to give a certain caterpillar the ability to mimic the look of bird droppings to fool it’s predators and make them search elsewhere for their meals? Or how does the Mimic Octopus evolve the “trait” to know how to mimic a flat fish, or a sea snake?
I find this extremely fascinating, where animals and insects can mimic things in their environment to further their species. Speaking of camouflage, the octopus changes are so dramatic with-in it’s environment, I am amazed how natural selection has given such an organism so much power over it’s own body.
So does anyone know how this works? How does evolution/natural selection give organisms such as these the physical charactoristics to produce such dramatic abilities with-in their environment?? Anyone know?
Well there’s nothing special about camouflage. Evolution has given various animals arms and brains and electric eels and eyes and termite metropolises and the ability to suspend a pregnancy and so many truly amazing things I don’t know where to start. If you get how those work, you get how evolution of camouflage works, it’s the exact same mechanism.
So there’s a whole bunch of catepillars of a certain species. Just by sheer random chance, one of them happens to have a mutation that turns their skin the color of bird droppings. It’s not a perfect disguise by any means, but does seem to make a tiny difference, so with a little luck this catepillar survives and its children tend to survive a little better. So each generation, a few more of the regular-colored 'pillars are eaten, and a few less of the whitish ones are, and eventually most of the population is whitish.
Then, again by pure random chance, one of the whitish 'pillars has another mutation that adds little dirty spots, making it look a little more like birdy poop. Again, it’s not a huge advantage over just whitish ones but even a tiny advantage adds up over generations.
Repeat and eventually you’ve got an amazing likeness.
Keep in mind these pure random chance mutations also result in the occaisional catepillar that instead of looking more like bird droppings, has neon ‘eat me’ signs flashing on its back. But these tend to get eaten more often and soon disappear from the gene pool.
Quercus’s answer is a basic summation of evolution in action. You’d be hard picked to find one exact cite, there are thousands on the general mechanism. To learn more, I highly reccomend the books by Richard Dawkins, particulalry The Blind Watchmaker and Climbing Mount Improbable.
The Panda’s Thumb by Stephen Jay Gould, goes into the mechanics of microevolutionary steps leading to things like camouflages and big things like evolving eyes.
