Earth to Kansas - Hello? Hello?, Geek Div.

Twice in this past week scientists have announced having uncovered fossils revealing so-called "missing links" - fossils of transitional forms, exactly the kind the creationists keep insisting don't exist.

The discovery you more likely heard about was in Utah, where

[a] "treasure trove" of fossils ... is helping paleontologists understand why some meat-eating dinosaurs evolved into vegetarians,[Scientific American reported on May 5]. ...

Scientists unearthed some 1,700 bones, which date to 125 million years ago, from the base of the Cedar Mountain rock formation in Utah.

The bones are of a new species, dubbed Falcarius utahensis, ("Utah sickle-maker," drawn from its sharp, curved 4-inch claws). What's significant about the find is that, as reported by the San Francisco Chronicle,

[i]t was "evolution caught in the act," said Scott Sampson, chief curator of the University's Museum of Natural History as he described the birdlike creature, barely more than 3 feet tall at the hip as an adult and 12 feet long from snout to tail. ...

"With Falcarius, we have actual fossil evidence of a major dietary shift, certainly the best example documented among dinosaurs. This little beast is a missing link between small-bodied predatory dinosaurs and the highly specialized and bizarre plant-eating therizinosaurs."

The legs, teeth, body bulk, and gut size all stood somewhere between earlier faster, smaller predators and later bulkier, larger plant-eaters.

As to why the change occurred, Sampson speculated that it "may have been directly linked to the spread of flowering plants about 125 million years ago." That involved a change

from a landscape dominated by ferns and pines to the advent of flowering plants on a large scale, Sampson said.

"Here was a new edible resource to be exploited," he said, "an open ecological niche, perhaps, that may have made Falcarius become a devoted vegetarian."

That, was, again, as Samson admitted, speculation - but, unlike the creationists, it's speculation based on what's known and on the logic of evolution because it suggests species change in interaction with environment. And it is at least intriguing, isn't it, that this transition from meat-eater to plant-eater emerged just about the same time that an abundance of edible plants was appearing?

But as I said, there were two announcements. The other, which I expect you were less likely to have heard, came two days earlier, last Tuesday. It probably made less of a splash because instead of involving dinosaurs, it involved fish. The Beeb gives the word:

Fossils of an ancient fish - dating back 450 million years, when the creatures had neither bones nor teeth - have been found in South Africa.

The finds, which are 50 million years older than any other fossil fish in Africa, will help provide a "missing link" in the evolution of early fish.

The first such specimen was found in 1994 and quickly nicknamed "Nelson" in honor of newly-elected President Nelson Mandela. Then, after a gap of 11 years, seven more were found in quick succession, leading to Tuesday's announcement. Richard Aldridge of the University of Leicester said that even without bones, the animals could be identified as fish.

"[T]he exceptional preservation displayed in these rocks enables us to recognise the eyes, scales and even the livers of the animals. The impressions in the shale are faint, but they are also clear and diagnostic."

Although analysis is preliminary, the researchers suspect the animals were swimming scavengers, living in a shallow sea during an ice age and feeding on whatever waste matter they could find. What's really important for the present discussion is that

"[t]hese exciting fossils will help fill in the 'missing link' in the evolutionary history of very early fishes," Professor Aldridge explained. ...

"The fossil record confirms that the evolution of fish was a step-wise event," explained Professor Aldridge.

"The various characters that make up a fish, or a vertebrate, didn't all appear at once - they were added one by one through evolutionary time."

I'd say "Take that, Kathy Martin!" except I see her over in the corner, her eyes closed and her fingers in her ears, shouting "LA, LA, LA, LA, LA, LA!"