Page 3 of 3 FirstFirst 123
Results 21 to 23 of 23

Thread: Chameleons and guided evolution?

  1. Top | #21
    Contributor DrZoidberg's Avatar
    Join Date
    Nov 2007
    Location
    Copenhagen
    Posts
    8,506
    Archived
    5,746
    Total Posts
    14,252
    Rep Power
    59
    Quote Originally Posted by excreationist View Post
    A sense of smell getting less sensitive is different from a hearing system that stops using the old system and uses a separate new system (that is generally inferior)....
    https://chameleonowner.com/can-chameleons-hear/
    "...Chameleons have a membrane at the side of their head which they use to hear low tones..."
    That's what you'd expect to see in a system where the driving force is something combining things at random. The digestive system of rabbits is in reverse, so it has to eat it's own poop after it's gone through once.

    It's all about survival. An important component in evolution is extinction events. Once every couple of hundred thousand years or so there's a major catastrophe wiping out a majority of all life on Earth, or in a large area of the planet. The surviving animals have plenty of space to spread out on, and at that point evolution can get very weird indeed. All creatures have plenty of these bizarre features that have stuck around since those events.

    This could be something that has arisen in one of those extinction events.

    Quote Originally Posted by excreationist View Post
    Having skin cells that can change colour has evolved in nature many times.
    Yeah though I don't think there are many animals that can change to pretty much any color like chameleons can. They can also have many different patterns - or a chaotic pattern.
    So what? Given enough time, anything that can evolve will evolve. It's not physically impossible for this function to evolve all by itself.

    Here's a video explaining the evolutionary mechanism behind all camoflaging evolution.
    https://www.youtube.com/watch?v=xWwgOIHSc1o

    Quote Originally Posted by excreationist View Post
    It's not a particularly complex or amazing feature. Humans can do it to. Our skin becomes darker when exposed to UV rays.
    Changing to any color is different from going darker over the course of days or years.
    I don't think you understand evolution, or you wouldn't have made that comment. It doesn't matter if a species does something a little, or a lot, or slowly or fast. If it can do it a little bit, that's all an evolutionary path needs to get started. If there's an evolutionary pay-off high enough it'll start down this road.

    The major difference between humans and chameleons is that they are cold blooded. So having the right temperature is critical. We're mammals and regulate our own inner temperature. So for us the colour change ability serves a different purpose. Namely having a balance between getting vitamine D and skin cancer.

    Quote Originally Posted by excreationist View Post
    One thing that keeps amazing me about creationists is the lack of interest. If you really cared about this, you'd look it up. You'd find a real scientific text book and learn about it. It's not that hard.
    If that's so easy then maybe skeptics on this forum could do it... I'm not happy with Politesse's attempt though - I think the color changing involves more than just simple skin stretching because I think there are at least 3 independent kinds of color changing elements. BTW "real scientific text books" are often A$100....
    There's loads of biologists on youtube explaining it. Any video sponsored by a real university is usually legit. Those text books cost that much because on university courses the professor gets to chose what books are required reading. By chance they often pick books they have written themselves and can bump up the price. You don't need to spend A$100. Also, this stuff isn't controversial in the least. There's plenty of excellent cheap books on it.

  2. Top | #22
    Senior Member excreationist's Avatar
    Join Date
    Aug 2000
    Location
    Australia
    Posts
    935
    Archived
    4,886
    Total Posts
    5,821
    Rep Power
    75
    Quote Originally Posted by DrZoidberg View Post
    Quote Originally Posted by excreationist View Post
    A sense of smell getting less sensitive is different from a hearing system that stops using the old system and uses a separate new system (that is generally inferior)....
    That's what you'd expect to see in a system where the driving force is something combining things at random
    I'd expect it to keep the perfectly good hearing system and just combine it with the other rather than also removing the old system (rather than just turning it off)

    Quote Originally Posted by DrZoidberg View Post
    Here's a video explaining the evolutionary mechanism behind all camoflaging evolution.
    https://www.youtube.com/watch?v=xWwgOIHSc1o
    About 30 seconds in your video says:
    Most people think chameleons change color for camouflage, but that's not it at all! Only the males can change color, and they do so to communicate danger to other nearby chameleons, or for a mating display.

    The video was still useful though because it says that chameleons use iridophores while I assumed it was like other animals and use chromatophores. At about 3 minutes in it also said that scientists had assumed that chameleons used the same techniques as cuttlefish and octopuses but a couple of years ago they investigated it more closely. (published in 2015?)

    Quote Originally Posted by excreationist View Post
    It's not a particularly complex or amazing feature. Humans can do it to. Our skin becomes darker when exposed to UV rays.
    Changing to any color is different from going darker over the course of days or years.
    I don't think you understand evolution, or you wouldn't have made that comment. It doesn't matter if a species does something a little, or a lot, or slowly or fast. If it can do it a little bit, that's all an evolutionary path needs to get started. If there's an evolutionary pay-off high enough it'll start down this road.
    One way color change is different from two-way.... also my comments about chromatophores are more relevant (though ultimately misguided based on recent science and things like iridophores)

    There's loads of biologists on youtube explaining it. Any video sponsored by a real university is usually legit. Those text books cost that much because on university courses the professor gets to chose what books are required reading. By chance they often pick books they have written themselves and can bump up the price. You don't need to spend A$100. Also, this stuff isn't controversial in the least. There's plenty of excellent cheap books on it.
    Yeah YouTube can be very good...

  3. Top | #23
    Contributor DrZoidberg's Avatar
    Join Date
    Nov 2007
    Location
    Copenhagen
    Posts
    8,506
    Archived
    5,746
    Total Posts
    14,252
    Rep Power
    59
    Quote Originally Posted by excreationist View Post
    I'd expect it to keep the perfectly good hearing system and just combine it with the other rather than also removing the old system (rather than just turning it off)
    Everything in nature has a cost. If the old system wasn't protecting them from whatever was killing them, or didn't help them catch their prey, but the other did they will switch.

    In nature there is a constant arms race. And what is good to have keeps changing.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •