Lampropeltis writes:
How can appearing EVER SO SLIGHTLY like bird droppings be advantageous?
There is a useful analogy to this, and it is this joke:
quote:
Two friends went camping and were sleeping in a tent when one heard a rustling sound. He woke up and recognized the odor and growls as those of a bear. He woke up his friend and told him that there was a bear on the loose in the campsite. Without saying a word the freshly-woken friend began to put on his running sneakers. Upon seeing this the other friend started laughing and incredulously asked, "You're not planning on outrunning that bear, are you?!? He'll chase you down!" The other friend continued to be silent and put on his other shoe. The friend again asked, "You do understand that you cannot outrun a bear, don't you?!?" At this point the other friend finished tying his running shoes sat up and with a gleam in his eye said to his interrogating friend, "I know that I cannot outrun a bear. All I have to do is outrun you!" and took off.
The insect or spider doesn't have to hide from the bird completely - it just has to hide slightly better than everyone else.
Remember that a bird may only get is a fleeting glance, and no bird has the big brain that allow us humans to recognise images (ever see a bird attack its own reflection?), and that these birds don't have a minute to sit in front of a picture to scrutinize it.
Consider also that this is hardly likely to be a disadvantage to the organism - it will be neutral at worst. 0.001% less of a chance of being eaten by a bird is still better than no change at all. So, because there is not real selection pressure acting against it, the tiny selection pressure acting for it can still make a difference. And, the more difference it makes, the more it increases the selection pressure, hence snowballing the effect until eventually the species looks as close to bird-droppings as it's morphology will allow.
Help inform the masses - contribute to the EvoWiki today!
Contributors needed for the following articles: Pleiotropy, Metabolism, Promoter, Invertebrate, Meiosis, DNA, Transcription, Chromosome, Tetrapod, Phenotype, Messenger RNA, Mammals, Appendix , Variation, Selection, Gene, Gametogenesis, Homo erectus and others.
Registration not needed, but if desired, register here!