Register | Sign In


Understanding through Discussion


EvC Forum active members: 65 (9162 total)
5 online now:
Newest Member: popoi
Post Volume: Total: 915,807 Year: 3,064/9,624 Month: 909/1,588 Week: 92/223 Day: 3/17 Hour: 0/1


Thread  Details

Email This Thread
Newer Topic | Older Topic
  
Author Topic:   Mimicry: Please help me understand how
Doddy
Member (Idle past 5909 days)
Posts: 563
From: Brisbane, Australia
Joined: 01-04-2007


Message 6 of 241 (411164)
07-19-2007 4:59 AM
Reply to: Message 1 by Lampropeltis
07-14-2007 3:04 PM


Tiny, tiny advantage = advantage nonetheless
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!

This message is a reply to:
 Message 1 by Lampropeltis, posted 07-14-2007 3:04 PM Lampropeltis has not replied

  
Doddy
Member (Idle past 5909 days)
Posts: 563
From: Brisbane, Australia
Joined: 01-04-2007


Message 45 of 241 (418566)
08-29-2007 12:38 AM
Reply to: Message 36 by MartinV
08-24-2007 12:21 AM


Re: mimicry isn't the problem, then
MartinV writes:
So why imperfect mimics are not improved by natural selection even more?
Have you presented a specific example of this?

Help to inform the public - contribute to the EvoWiki today!
What do you mean "You can't prove a negative"? Have you searched the whole universe for proofs of a negative statement? No? How do you know that they don't exist then?!

This message is a reply to:
 Message 36 by MartinV, posted 08-24-2007 12:21 AM MartinV has not replied

  
Newer Topic | Older Topic
Jump to:


Copyright 2001-2023 by EvC Forum, All Rights Reserved

™ Version 4.2
Innovative software from Qwixotic © 2024