Posted on 07/13/2006 1:21:13 PM PDT by presidio9
Finches on the Galapagos Islands that inspired Charles Darwin to develop the concept of evolution are now helping confirm it by evolving.
A medium sized species of Darwin's finch has evolved a smaller beak to take advantage of different seeds just two decades after the arrival of a larger rival for its original food source.
The altered beak size shows that species competing for food can undergo evolutionary change, said Peter Grant of Princeton University, lead author of the report appearing in Friday's issue of the journal Science.
Grant has been studying Darwin's finches for decades and previously recorded changes responding to a drought that altered what foods were available.
It's rare for scientists to be able to document changes in the appearance of an animal in response to competition. More often it is seen when something moves into a new habitat or the climate changes and it has to find new food or resources, explained Robert C. Fleischer, a geneticist at the Smithsonian's National Museum of Natural History and National Zoo.
This was certainly a documented case of microevolution, added Fleischer, who was not part of Grant's research.
Grant studied the finches on the Galapagos island Daphne, where the medium ground finch, Geospiza fortis, faced no competition for food, eating both small and large seeds.
In 1982 a breeding population of large ground finches, Geospiza magnirostris, arrived on the island and began competing for the large seeds of the Tribulus plants. G. magnirostris was able to break open and eat these seeds three times faster than G. fortis, depleting the supply of these seeds.
In 2003 and 2004 little rain fell, further reducing the food supply. The result was high mortality among G. fortis with larger beaks, leaving a breeding population of small-beaked G. fortis that could eat the seeds from smaller plants and didn't have to compete with the larger G. magnirostris for large seeds.
That's a form of evolution known as character displacement, where natural selection produces an evolutionary change in the next generation, Grant explained in a recorded statement made available by Science.
Explain how the same species, demonstrating smaller average beak size is a sign of evolution. If there were no smaller beaked birds in the general population a few decades ago, there might be an inkling of an inkling of a chance that it signalled the beginning of a possibility of some form of evolution.
Your comment is a prime example of how you "old earthers" will jump on anything to help bolster your point of view, even if it really does no such thing. All this shows is that those with smaller beaks get more food and are stronger and more viable, therefore more likely to breed. The result is more birds with small beaks. Of course, I guess it all comes down to what the meaning of "evolution" is (if you can decide the meaning of "is" too).
The definition of "species" is not "squishy". It is somewhat ambiguous at borders, because of the nature of speciation, but the term is well-understood regardless.<<
Since the advent of the theory of evolution, the conception of species has undergone vast changes in biology; however no consensus on the definition of the word has yet been reached. The most commonly cited definition of "species" was first coined by Ernst Mayr. By this definition, called the biological species concept or isolation species concept, species are "groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups". However, many other species concepts are also used (see other definitions of species below).<<
http://en.wikipedia.org/wiki/Species
That doesn't sound squishy to you? It is not well understood, it is flexible to the point of uselessness.
>>Crappy logic like evolution is both a theory and a fact.<<
>>How is this logic "crappy"? Please explain to show that you understand what is meant by the statement.<<
Evolution cannot be both a theory and a fact. Biologists have been remiss in their duty to use language rigorously. ToEs attempt to explain the observations that are really the fossil record. Of course once you say the word evolution, everything gets written in stone (I hope you appreciate that!). Now we have whole populations of scientists that think in terms of evolution...but they really don't have mountains of results from it.
The psych term for it is homosocial reproduction. You choose your successor based on self image.
This is a mechanism that helps assure paradigm shifts won't occur easily. But we are near one in biology. I'm looking forward to it.
I have mentioned several biological tech advances that don't require any evolutionary belief or training, but are far more important to humanity. When I ask about the usefulness of ToEs, I get sent to pages that describe computer genetic algorithms that spit out obscure circuit designs or other bizarre fringy stuff.
But there is one thing I have to note:
Please explain to show that you understand what is meant by the statement.
I have not asked you to show me that you know what you write. I may dispute what you write. I may disagree with you. I may try to persuade you. I may ask more about things you say. If insulted, I WILL return the favor. I will always remind the pompous if they said something foolish. A very bright moron once said we don't use epistemology in science. I still laugh at him and he hates it.
So why am I obligated to prove my knowledge to you?
BTW I love citations.
This is not a tagline or a gotcha, I would really like to know why you feel that?
DK
More importantly, do they taste good with a bit of garlic and clove?
Any of them evolved into a duck or an eagle yet??
More importantly, do they taste good with a bit of garlic and clove?<<
Okay, time to start sharing spotted owl recipes!
DK
... or Quimby?
Love that show.
"I loved your last post.
It has all the intellectual power of a grade school tirade. "
Look, if you can't post with even a modicum of maturity, please don't bother posting to me anymore.
Have a nice day.
You are a funny guy!
Did you even think about your post? Did you compare it to other posts I've made.
You insulted me. I came back at you, but I also included succinct arguments to chew on.
You weren't up to the task.
You're just impotent on this subject.
Go whine somewhere where your feelings won't get hurt.
Are you really a guitar person, or just a drummer?
DK
100 Locate new crevo thread
110 Cruise thread for an evo's post
120 Post reply: "Evolution is trash. You're an idiot. Call me when a bird turns into a toad."
125 If evo replies, hit abuse button.
130 If thread is moved to Chat or Backroom, GOTO 100.
135 Cruise thread for another evo's post
140 Post reply: "Evolution is only a theory. All evos are atheists. Hitler loved Darwin."
145 If evo replies, hit abuse button.
150 If thread is moved to Chat or Backroom, GOTO 100.
155 Cruise thread for another evo's post
160 Post reply: "Go back to DU. Evolution is nonsense. Stop bashing my religion."
165 If evo replies, hit abuse button.
170 If thread is moved to Chat or Backroom, GOTO 100.
175 Cruise thread for another evo's post
180 Post reply: [randomly selected text from creationist website].
185 If evo replies, hit abuse button.
190 If thread is moved to Chat or Backroom, GOTO 100.
195 GOTO 110
And they always have to get the last word.
Sorry I frightened you.
Maybe you need to go to a Disneyland thread.
You insulted me, remember?
DK
Please document this claim.
That's sooo BASIC.
Hey, I started with an Apple ][, so that's what I know.
What, that species interbreeding is more populsr than biologists want to explain?
It's in the definitions. Doh.
DK
Lights out, this this thread is done.
DK
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