How Do Evolved Animals Change Colour?

Question

There are two similar parakeets that live in Australia: the Budgerigar and the Bourke's parakeet. According to evolution, would these two species have come from the same place?

If the answer is yes: Why is it, that there is no possible way that you could get a red budgerigar through mutations while the Bourke's has red in it? You could mutate the budgie for years and get all sorts of greens, blues, yellows, blacks, whites, curly feathers, funny body shapes... but no matter what, you will not get red (this is proven by the way, you will never get a colour from a bird that wasn't in it originally). However with the Bourke's you can.

I'm sorry if this is a really ignorant and obvious question. How do animals change colour through evolution when they don't have the colour in them in the first place? Or even, how could the colour disappear and never reappear again? You could have generations of pure white funny shaped birds but they will still produce offspring that look like (cont)

Answer 1

The crux of your problem appears to be this error: "no matter what, you will not get red (this is proven by the way, you will never get a colour from a bird that wasn't in it originally)."



That is simply not true.



The coloration of bird feathers doesn't work the way you would normally think it does. With most things, like skin, fur, flower petals, etc... the coloration is due to pigments that produce particular colors. However, in feathers the color is not only due to pigmentation but also due to refraction. The size of air pockets within the barbs on feathers control the specific wavelength of light produced. This means that a slight change in the size of air bubbles can produce a variety of colors, from green to blue, and even into the ultraviolet range.



If you take a look at a blue jay's feathers, for example, you will find no blue pigment at all. The color is simply a product of light diffraction, like the colors from a prism, but only a specific part of the spectrum.



Still, we're talking about the color red. Red is produced by the pigments called carotenoids, the same thing that colors carrots (hence the name). Actually, carotenoids can produce colors from red to orange to yellow. In other words, the pigment that makes yellow in one species is the same pigment that makes in red in the other. See:

http://www.birdersworld.com/brd/default.aspx?c=a&id=667



So, you have a common ancestor for both species it could have had some or all of the traits found in both of the species that descended from it. Furthermore mutations, genetic drift, and natural selection could have produce all of the changes since then. This wasn't something that happened overnight, but over hundreds of millions of generations.



Furthermore, it often only takes a single mutation to make a single new color. For example, the allele that produces blue eyes in humans is apparently a relatively new mutation that first appeared 6,000 to 10,000 years ago. Apparently people found blue eyes attractive, because the allele spread, and is the source for every blue eyed person alive today. See:

http://www.sciencedaily.com/releases/2008/01/080130170343.htm



Finally, while any animal will normally only give birth to offspring with only tiny changes from the parents, if you accumulate changes across many many generations the descendants will often be quite different from their ancestors. Large scale evolution of animals usually takes far too long for humans to see in their lifetimes, but the fossil, genetic, morphological, and geographic evidence all support that these species, and all others, most likely evolved from a common ancestor, even though they now have visible differences.



Hope that helps! :-)

Answer 2

The answer is pretty obvious, just from your description.



The mutation that causes red plumage clearly occurred *after* the branching between the two lineages ... their common ancestor did not have the "red plumage" allele. That explains why the budgies will not have a naturally occurring red form, but the Bourke's parakeet does.



>"You could mutate the budgie for years and get all sorts of greens, blues ..."



That phrase "mutate the budgie" is a bit odd. You can't "mutate" a species. You can *breed* a species, but you can't "mutate" it. The occurrence of mutation is not predictable or controllable ... much less a *specific* mutation. A species could go tens of thousands of generations without the specific mutation you are thinking of. And that is evidently what happened at some point to the Bourke's parakeet. That is something that can easily happen over thousands to *tens of thousands* of years that might never happen in even the few hundred (?) years that we have been domesticating budgies and parakeets.



So yes, you are correct that a human breeder could breed a bird for dozens of generations and never produce a bird with a color not in its genes. But that does NOT "prove" that such a color could not occur spontaneously through a mutation in one of those genes over the course of tens of thousands (not just a few dozen) generations.



This is an example of the "no new information" argument that you will find -- in many different guises -- in Creationist web sites. The argument basically goes: "scientists are unable to produce a controlled experiment (like breeding) showing the mutation of a new gene that didn't exist before ... therefore there is no evidence that new genes (new 'information') can occur through mutation." But this is making a *fundamental* mistake! There are other kinds of evidence besides controlled experiments. The way we see that such mutations have occurred is by looking at two species that vary in a particular trait, and showing that this trait is traceable to a specific kind of mutation (a point mutation, frameshift error, duplication error) that we know to occur all the time. We don't have to "witness" the particular mutation "as it happens" ... we just look for the tell-tale markers that it did occur ... in the same way that we don't have to "witness" a crime or a fire "as it occurs" to know that it did occur ... we just look for the tell-tale evidence (the clues in a crime, or the ashes of a burned down forest) of the event.



I don't know if the specific genetic basis for color differences in budgies and parakeets has been studied ... but I do know that the genetic basis for plumage colors in birds in general has been studied extensively. (See source.)

Answer 3

I'm not familiar with those parakeets but i'll assume everything about them here is true.There are a few possible solutions that jump to mind.I'll focus on a couple probable solutions.(1)The 2 shared a common ancestor long ago.That ancestor carried the *red* gene.That ancestor had offspring that split up.(living things certainly like to move)The 2 relatives eventually became seperated into 2 different species.No longer able to mate with each other.there was a selective pressure(we'll say for mating purposes,this is known as sexual selection)in the bourke's lineage that favored the red gene.This gene would remain more frequent and intact because of selective pressure. However,In the budgerigar,that gene could have become fossilized(see below)because it wasn't favored by mating budgerigar's.Once a gene becomes*fossilized*,it can't be teased out. (2)Another possibility is that the bourke's red gene is novel to that species.It appeared after the split.In either scenario,they could still share a common ancestor. " How do animals change colour through evolution when they don't have the colour in them in the first place?"Answer:we've identified many ways in which this can occur.See here :http://evolution.berkeley.edu/evolibrary/article/0_0_0/mutations_01 This is an amazing ongoing experiment where bacteria evolved the ability to digest citrate.>>>> http://scienceblogs.com/loom/2008/06/02/a_new_step_in_evolution.php *a fossil gene means that a trait or characteristic is lost and can never come back.See also broken genes. For more information on evolution:works http://evolution.berkeley.edu/ It's a really good site that's easy for even beginners to follow.If you want to have a little more fun,check out http://www.talkorigins.org/ or http://www.pandasthumb.org/ This is a good sight if you want to see actual scientists,teachers,etc,debate with creationists and Intelligent design proponents.If you are serious and curious,sign up and ask some questions. http://www.iidb.org/vbb/forumdisplay.php... A good book to start off with is The Selfish Genehttp://www.amazon.com/Selfish-Gene-Anniv... Or Evolution: The Triumph of an Idea http://www.amazon.com/Evolution-Triumph-...

Also you can read ,in no particular order.Climbing Mount Improbable,Genome An Autobiography Of A Species in 23 chapters,The Blind Watchmaker,The Ancestors Tale,The Mating Mind,The Red Queen, From D.N.A. To Diversity, http://www.amazon.com/Ancestors-Tale-Pil... A few more i thought of Deep Time : Paleobiology's Perspective ,Genetics in the Wild , Frogs, Flies, and Dandelions: Speciation--The Evolution of New Species,The Making of the Fittest: DNA and the Ultimate Forensic Record of Evolution http://www.amazon.com/Making-Fittest-Ult... ,

Endless Forms Most Beautiful: The New Science Of Evo Devo And The Making Of The Animal Kingdom by Sean B. Carroll

http://www.amazon.com/s/ref=nb_ss_b/002-...

Answer 4

<< According to evolution, would these two species have come from the same place?>>



Evolutionary theory is concerned with their most recent ancestry, not their location. I don't happen to know how closely these birds are related in comparison to other parakeets. Colour can be a poor indicator for that. For example, the closest living relatives of black panthers are predominantly yellow. The closest relative of the white polar bear is the brown bear.



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Colour is often very variable. Think about people. Very dark black skin through a range of browns, reds, pinks... Very dark hair through browns, blondes, even reds... Brown eyes, or would you prefer blue or green? Variation happens.



And should a particular variation happen to prove advantageous, perhaps because it helps you blend in better with the environment or the ladies happen to find that particular tone sexually stinulating for no particular reason beyond that, then there's a built-in tendency for that tone to spread through the population due to numbers of descendants. Vaguish tones can then also become more strongly pronounced.

Answer 5

that's strongly believed (with the help of a lot of people and scientists alike) that people won't save evolving. it incredibly is principally using fact there relatively is not any choose for Homo Sapiens (people) to try this from now on. get what i mean? We people are completely superb and chuffed the way we are. Our species relatively has no would desire to conform as a fashion to stay to tell the story and save our species from transforming into extinct. Over tens of millions of years many animals have stepped forward as a fashion to regulate the hard annoying circumstances that nature throws at them. as an occasion that's a great deal believed that we people stepped forward from apes. those apes we stepped forward from as quickly as lived in timber yet at last, in seek of greater foodstuff factors, began coming near the floor, and, over 1000's of years, settled on the floor. our bodies began changing in accordance to the greater modern-day ecosystem around us. We began walking upright, grew to become much less furry(!) etc. people are a superb species interior the international and in nature using fact we've the only element different creatures don't have. intelligence. no longer plenty a great deal threatens our existence and so we are able to, maximum possibly, by no potential would desire to conform anymore. yet then the concept of evolution is likewise a great deal arguable. So possibly we've by no potential even stepped forward and so by no potential will...you by no potential understand with those issues....

Answer 6

You should check with chameleon for a better picture from horse's mouth!