Hi Holden,
Originally posted by Holden McGroin
It took about 3 minutes in Google to find information about possible evolutionary links between dinosaurs and birds and another about our possible ancestors and ape ancestors.
This will probably be my last response on the BB tonight, as tomorrow is obviously the busiest day of the week for me. Anyway, unfortunately what you're doing above is precisely what I was referring to in a previous post. A few species are found that resemble another species and then there are speculations that this is an "ancestor." Scientifically its the equivalent of finding a Camaro in the junk yard at one level in a stack, and a Corvette beneath it and speculating that the Camaro developed from the Corvette based on functional similarities between the two.
I wish I could cram several years of reading on this subject into one thread, but it's not going to be possible. Look let me oversimplify and say that if evolution were working according to the traditional hypothesis referred to as
"phyletic gradualism" presupposed by Darwin, we would see an easily discernable pattern of chains in the fossil beds, as species clearly "mutated" into other species. This however is not what we find. Eldredge and his late Colleague Stephen J. Gould have written reams on this subject alone:
"No wonder paleontologists shied away from evolution for so long. It seems never to happen. Assiduous collecting up cliff faces yields zigzags, minor oscillations, and the very occasional slight accumulation of changeover millions of years, at a rate too slow to really account for all the prodigious change that has occurred in evolutionary history. When we do see the introduction of evolutionary novelty, it usually shows up with a bang, and often with no firm evidence that the organisms did not evolve elsewhere! Evolution cannot forever be going on someplace else. Yet that's how the fossil record has struck many a forlorn paleontologist looking to learn something about evolution." (Eldredge, Reinventing Darwin: The Great Evolutionary Debate, 1996)
"It is, indeed, a very curious state of affairs, I think, that paleontologists have been insisting that their record is consistent with slow, steady, gradual evolution where I think that privately, they’ve known for over a hundred years that such is not the case." (Eldredge, "Did Darwin Get It Wrong?" Nova 11/1/81))
"Paleontologists have paid an enormous price for Darwin’s argument. We fancy ourselves as the only true students of life’s history, yet to preserve our favored account of evolution by natural selection we view our data as so bad that we almost never see the very process we profess to study. ...The history of most fossil species includes two features particularly inconsistent with gradualism: 1. Stasis. Most species exhibit no directional change during their tenure on earth. They appear in the fossil record looking much the same as when they disappear; morphological change I usually limited and directionless. 2. Sudden appearance. In any local area, a species does not arise gradually by the steady transformation of its ancestors; it appears all at once and ‘fully formed.’" (Gould, The Panda’s Thumb, 1980)
"Most families, orders, classes, and phyla appear rather suddenly in the fossil record, often without anatomically intermediate forms smoothly interlinking evolutionarily derived descendant taxa with their presumed ancestors." (Eldredge, Macro-Evolutionary Dynamics: Species, Niches, and Adaptive Peaks, 1989)
Then there is the infamous Cambrian Explosion, the Biological Big Bang, that totally knackers phyletic gradualism:
"The “Cambrian explosion” refers to the geologically sudden appearance of many new animal body plans about 530 million years ago. At this time, at least nineteen, and perhaps as many as thirty-five phyla of forty total (Meyer et al. 2003), made their first appearance on earth within a narrow five- to ten-million-year window of geologic time (Bowring et al. 1993, 1998a:1, 1998b:40; Kerr 1993; Monastersky 1993; Aris-Brosou & Yang 2003). Many new subphyla, between 32 and 48 of 56 total (Meyer et al. 2003), and classes of animals also arose at this time with representatives of these new higher taxa manifesting significant morphological innovations. The Cambrian explosion thus marked a major episode of morphogenesis in which many new and disparate organismal forms arose in a geologically brief period of time.
To say that the fauna of the Cambrian period appeared in a geologically sudden manner also implies the absence of clear transitional intermediate forms connecting Cambrian animals with simpler pre-Cambrian forms. And, indeed, in almost all cases, the Cambrian animals have no clear morphological antecedents in earlier Vendian or Precambrian fauna (Miklos 1993, Erwin et al. 1997:132, Steiner & Reitner 2001, Conway Morris 2003b:510, Valentine et al. 2003:519-520). Further, several recent discoveries and analyses suggest that these morphological gaps may not be merely an artifact of incomplete sampling of the fossil record (Foote 1997, Foote et al. 1999, Benton & Ayala 2003, Meyer et al. 2003), suggesting that the fossil record is at least approximately reliable (Conway Morris 2003b:505)." (Meyer, PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON, 117(2):213-239. 2004, "The origin of biological information and the higher taxonomic categories")
As Gould pointed out:
"Stepping way back and looking at too broad a scale, one might discern some sort of progress in life’s history. ...But the pattern dissolves upon close inspection. Most structural complexity entered in a grand burst at the Cambrian explosion, and the history of Phanerozoic life since then has largely been a tale of endless variation upon a set Bauplane. We may discern a few ‘vectors’ of directional change - thickening and ornamentation of shells...--but these are scarcely the stuff of progress in its usual sense." (Gould, "The Paradox of the First Tier: an Agenda for Paleobiology," Paleobiology, 1985)
- SEAGOON
