read this, it refutes the article you linked
One aspect of evolution that does not make sense.....
by EndofMysteries 153 Replies latest watchtower beliefs
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EndofMysteries
Chameleons' mastery of camouflage goes further than anyone expected - it seems they can fine-tune their colour changes to the visual systems of specific predators.
Devi Stuart-Fox at the University of Melbourne, Australia, and colleagues studied the Smith's dwarf chameleon (Bradypodion taeniabronchum), which lives in South Africa.
This critically endangered chameleon can alter its colour palette in milliseconds, either for camouflage or for social signalling.
The team captured eight males and eight females of the species. They placed them on a branch and presented them with realistic models of two of their biggest predators: the fiscal shrike (a bird that impales chameleons on thorns before eating them) and a venomous tree snake called the boomslang.
Bird threat
Using a spectrometer, the team took readings of the colour shades and brightness of the background and the chameleon. Then, after the chameleon had spotted the model predator and changed colour, they took another set of readings.
The chameleons colour-matched their backgrounds much more closely when presented with a bird than a snake, the team found.
However, when the team modelled the visual systems of both predators, they found that the chameleon still appeared better camouflaged to the snake than the bird, thanks to the snake's relatively poor colour vision. In the presence of a snake, it seems, the chameleons just don't have to try as hard.
Subtle changes
The researchers noticed that the chameleons were also consistently paler, compared with their background, when presented with the tree snake.
"This is probably because while birds usually approach from above, putting the chameleon against a dark background, snakes usually approach from below, putting it against a background of a light, bright sky," says Stuart-Fox.
Other animals can adjust their defensive behaviour or appearance in response to different predators.
For instance, the ground squirrel pumps more hot, infrared emitting blood into its tail
when it spots an infra-red sensing rattlesnake. But this is the first time anyone has observed an animal modifying that change to best avoid being seen. -
cofty
EOM - Chameleons have evolved an ability to control their colour changes. Evolution has selected for colour change over many generations. As I said above it probably had more to do with communication and the camouflage was secondary. Even a tiny advantage can be selected for and become more sophisticated through an accumulation of favourable mutations over many generations. What's not to understand?
The fact that some fish also learned the trick is an example of convergent evolution and shows that it had a selective advantage in two different environments.
You didn't read the link did you?
PS - your link didn't refute anything, it jsut provided some very interesting research on how chameleons can control their colour.
Are you just arguing because your bored?
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EndofMysteries
I read the link, as you said chameleons changing their appearence to camouflage and hide from predators is a myth, which the link and article I then posted refrutes that claim.
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EndofMysteries
" There is this myth that chameleons change
colour to blend in with their surroundings, but this is actually not true. " That's what your article said,,,,,my article says, "
Using a spectrometer, the team took readings of the colour shades and brightness of the background and the chameleon. Then, after the chameleon had spotted the model predator and changed colour, they took another set of readings.
The chameleons colour-matched their backgrounds much more closely when presented with a bird than a snake, the team found."
Both articles have opposite claims, my article is backed by research and study.
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cofty
OK - so chameleons are even more clever than I thought.
Thanks for the link.
What's your problem? Is it just your inability to imagine how this could evolve step by step? If so do some more reading.
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Apognophos
There's actually some dispute about this. I was reading the talk page for Wikipedia's Chameleon article yesterday and chameleon owners were arguing about whether chameleons hide using camouflage. Some of them are positive that the kind of chameleon they own does not match its environment, and maybe they're right and some species do not do this. Perhaps we should instead move the discussion underwater, as many species indisputably use camouflage deliberately (albeit instinctually) to hide from predators: Underwater camouflage.
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EndofMysteries
Okay I'll accept your backing out of this debate.
What is my problem?
Okay, chart out an evolutionary process that will allow humans to camouflage exactly like chameleons do, whether it takes 1,000 years, 1 million years, or 1 billion years, without direct scientists intervention, at some point in the future a human can do what chameleons do, and it must be by evolution only.
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EndofMysteries
apognophos - my theory assuming the species are the same is that the chameleons are comfortable w/ their human handlers so their color changes are only mood based since they don't feel the need to camouflage. That theory could be tested by presenting them w/ predators, etc, out of their comfort zone and seeing what happens.
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cofty
EOM - You are like a 6 year old demanding that a maths teacher explain differential calculus to him NOW!!!!
Go read some basic textbooks and when you have realised how misguided most of your questions are come back and ask for help with some sensible ones.
Here are a few suggestions...
"Endless Forms Most Beautiful" by Sean B. Carroll
"The making of the fittest" by Sean B Carroll
"Evolution, what the fossils say" by Donald Prothero
"The Greatest Show on Earth" by Richard Dawkins
"Why Evolution is true" by Jerry Coyne
"Your Inner Fish" by Neil Shubin
"Life Ascending" by Nick Lane
For starters take an hour or so to read the Common Ancestry thread.
when it spots an infra-red sensing rattlesnake. But this is the first time anyone has observed an animal modifying that change to best avoid being seen.
colour to blend in with their surroundings, but this is actually not true. "