Quirky "fishapod" crawls onto our family tree. (Thanks Jen!)
Let's see how many creationists want to talk about this. ;-)
(Not to mention Archaeopteryx etc...)
It should also be pointed out, as someone else commented, that there really isn't such a thing as a "missing link". This terminology was invented by creationists trying to find a way to argue against science. It takes a rather in-depth ignorance of the subject to think that evolution is a single chain from *poof* having life begin, and *tada!* having us as the end of the evolutionary chain. And that is putting it -very- nicely.
Starting with the concept of "life", which is something religious wackos have essentially no real grasp of... we have something that is actually a progression of proteins, molecules etc... those which "work", stay. Those which don't... don't. For instance, the protein that causes mad cow disease (and mad deer) isn't a living thing... although it acts like one. It's simply a protein that has found a way to travel and reproduce as such... where does this fall?
Religious nuts like to think of "life" as this magical gift from god that just starts... magically... at some point... when God chooses to give you a soul or something... (explain plants? explain bacteria? are they alive? how about viruses? where do you draw the ARBITRARY line?)
In actuality, those with any real scientific understanding know that "life" is an arbitrary classification we give things that portray certain characteristics. For instance, let's look at the criteria listed on Wikipedia's Life page:
Although there is no universal agreement on the definition of life, the generally accepted biological manifestations are that life exhibits the following phenomena:I don't see any mention of a magical gift from God... or a soul in there... do you? I do however, see a set of scientifically testable criteria. Funny that...
- Organization - Living things are comprised of one or more cells, which are the basic units of life.
- Metabolism - Metabolism produces energy by converting nonliving material into cellular components (synthesis) and decomposing organic matter (catalysis). Living things require energy to maintain internal organization (homeostasis) and to produce the other phenomena associated with life.
- Growth - Growth results from a higher rate of synthesis than catalysis. A growing organism increases in size in all of its parts, rather than simply accumulating matter.
- Adaptation - Adaptation is the accommodation of a living organism to its environment. It is fundamental to the process of evolution and is determined by the individual's heredity.
- Response to stimuli - A response can take many forms, from the contraction of a unicellular organism when touched to complex reactions involving all the senses of higher animals. Plants also respond to stimuli, but usually in ways very different from animals. A response is often expressed by motion: the leaves of a plant turning toward the sun or an animal chasing its prey.
- Reproduction - The division of one cell to form two new cells is reproduction. Usually the term is applied to the production of a new individual (either asexually, from a single parent organism, or sexually, from two differing parent organisms), although strictly speaking it also describes the production of new cells in the process of growth.
From these beginnings, fitting the theory of "Survival of the Fittest", as atoms followed the laws of physics and molecules formed... and proteins etc... and these continually followed the mantra of the best "surviving" and the imperfect ones failing... we grew. "Life" grew. There was no magic moment when Life BeganTM. Things simply progressed... and this progression, from the start... was as a tree with a multitude of branches... ever growing. Not a single chain... but each "offspring" having it's own offspring... and essentially all of them slightly unique... and as these branches grew... some grew ever further apart from each other as each found different traits beneficial to survival... either through reproductive traits... or survival traits.... depending on geography, habitat, "food", mate availability etc... any number of different factors... and so we progressed from organic compounds... proteins... single celled organisms... multicellular organisms... towards things like primitive plants and animals as the first "major" branches of the tree of life started diverging in more dramatic ways. (See Wikipedia's article on "Evolution" for another thourough explanation.)
Many of these branches exist simultaneously, in similar forms. Some reach essentially efficient stable forms and remain unchanged for millions of years, such as Sharks. Some have been merely a twinkle in the eye of time... some have held sway over the earth for millions of years... only to be eventually unseated by a different form... such as the transition from the dinosaurs to mammals as we now know them as the dominant life forms (leaving out insects and such, who ridiculously outnumber us).
But back to what I was saying... as someone earlier said... as much as such a "missing link" is a transitional life form... which essentially all live on earth is... then we must not forget that we are simply a transitional life form between our more ape like ancestors and relatives, and some future "super-human" form. We are a chronospecies... one that will inevitably cease to exist simply due to the passage of time. Any real study of the fossil record will demonstrate innumerable species that have changed so dramatically over the course of time, that if you took the animal now, and one of it's ancestors from millenia past... they would not be able to interbreed, having changed so dramatically in the interim.
I have no problem addressing these complex issues scientifically, and adjusting the models as evidence and data requires... but oversimplification and rote denial of mountains of factual data and scientific evidence in pursuit of elevating a belief, based on ignorance, to the level of supposed credibility... I have a rather serious problem with that.
For instance, there has been an issue of an evangelical nutcase archaeologist who claims to have discovered organic "tissue" inside T-Rex bones etc... while I think that she is a nutjob, given many of her public statements... I won't discount her findings over it... I simply want to see more research done along those lines. If the models of biological material decay were wrong, address them... if there really is some other problem with the models... address them. Failure to address an issue when it doesn't fit the expected guidelines, out of a fear of what it might mean, is to completely fail the goals of science.
(Read this article about the T-Rex, from the perspective of some Creationists, to get an idea how ridiculous these people's beliefs are. For instance, take every living species of animal alive today, and take a single male and female from each (not to mention that the bible specifies that SEVEN of every type of clean animal and SEVEN of every type of bird... AND food enough for themselves and every single animal... aside from "every kind of food"... or the fact that the waters were so deep that they covered the entire earth COMPLETELY, 20 feet deeper than the tip of the highest mountain on earth... or that all mankind was killed except for Noah, his wife, their 3 sons, and their wives... and all of humanity is supposedly now descended from those 8 people... or maybe more, as polygamy was accepted in those days... the list goes on and on and on...) and see if you can fit them all onto a single boat of the size Noah built. Not to mention ignoring the fossil record and archaeological evidence concretely dating when these animals lived. Or ignoring the fact that due to inbreeding, almost all of these species would die off etc... it's simply scientifically ludicrous bullshit... but that doesn't stop these nutjobs from throwing mountains of science out the window, while clinging to straws... even scientific ones... to try to prove they're right.)
We have creationists scrambling to cling to this issue as supposed proof of young earth theory etc... and others denying the evidence outright, without even looking into it, for fear that it might give the young earthers ground to stand on.
(Let's not forget that the bible explicitly lists the animals created during creation; cows, birds etc... and fails to mention the kind of life we know actually came about, billions of years after the formation of our planet, which in turn came billions of years after the beginning of the universe as we know it... to put this a little more clearly for you... sit down in front of a nice old analog wall clock, and starting at midnight, watch the second hand sweep around... second after second... as it travels around the face of the clock 1,440 times over the next 24 hours... and just before midnight, 24 hours later, as the second hand ticks off that one final second... that single second, in relation to the previous 23 hours, 59 minutes and 59 seconds, represents more time than cows as we know them, and ourselves, have existed in relation to the age of the universe as we know it.)
UPDATE - WEDNESDAY, APRIL 12, 2006:I think it's pretty safe to say that fundamentalist Christians are broken in the head... but let's not let our fear of their delusional rantings prevent us from addressing what could be shocking findings about fossilization and such. Keep our eyes on the truth for the sake of the truth, the whole truth, wherever it may lead us.
Please see my later post Visual timeline of evolution that has a link to a much better visual example then my clock metaphor. (Evolutionary Timeline)