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Lecture 2:

Listen to part of a lecture in a zoology class.

Professor: Okay, we’ve been talking about birds, modem birds and their environments but it might be interesting to say something about ancient birds, especially the one called archaeopteryx. Difficult word I know, but all it means is“ancient wing”.

Thee first archaeopteryx was discovered ed in 1861, fossilized in a piece of stone from a quarry in Germany. From a paleontologist point of view this was a real stroke of luck. Not only were the fi agile bones of this ancient bird extremely well preserved, and that’s pretty rare for a bird, which is why we don’t find very many of them in the fossil record, but the fine details of this fossil were really quite extraordinary. You could even detect impressions of the feathers on it, amazing hull? Yes, Mike?

Student: Why was it that details like that showed up in this particular fossil?

Professor: Well, I mentioned before that the archaeopteryx fossil was found in a quarry, you know, where people cut stone, in this case exceptionally fine grained limestone. And the point is, the particles that this limestone was made of was so fine that the limestone preserved much of the fossil in exquisite detail. And as I said revealed impressions of details even as small as the lines in a feather.

But that’s pretty rare. There are not many fossils of ancient birds in general, being so fi agile, much less archaeopteryx fossils. So we don’t know for sure as much as we’d like to but there are lots of opinions .It’s like, say, the Mona Lisa, you guys have seen copies of that painting right? The Mona Lisa. Well one of the great tilings about it is that each person who sees that painting understands it a little differently, according to their own biases. You might say that the archaeopteryx is a scientific Mona Lisa.

Student: How so?

Professor: Oh, well, ornithologists who study modem birds tend to see the archaeopteryx as an early ancestor of the birds we see today, but paleontologists, the ones who study fossils and forms of ancient life, point out its similarity to some dinosaur species.

I mean, it is very different from modem birds in some important ways, I mean, there is no beak, the tail is long and bony the way a reptile’s is rather than short and stubby like a modem bird’s and it has claws at the end of what are called its wing fingers. They are generally absent in modem birds.

Student: So ornithologists think it’s a bird and paleontologists say it isn’t?

Professor: Oh, did I say that? Oh no, no, I’m sorry. That’s not what the debate is about.The archaeopteryx had feathers and creatures with feathers are classified as birds.

Student: So then, what is the debate about?

Professor: Okay. Well, like I said, even with the lack of a beak and with its tail and claws, it’s still classified as a bird.The debate is, well, evolutionarily speaking, where does archaeopteryx fit? For the paleontologist who studies other dinosaurs of that period, it’s well, in a lot of ways nothing all that unusual.

Student: Except for the feathers.

Professor: Except for the feathers, exactly. Paleontologists see the archaeopteryx in terms of its wider evolutionary relationships .They see it as a kind of link, almost, between dinosaurs and modem birds or at least closely related to one.

And for the ornithologists, the archaeopteryx is a bird with exceptional features and the earliest bird on record.A basic belief of ornithologists is that birds evolved or that their evolution is closely related to their developing the ability to fly. But some of those features I mentioned earlier, the lack of a birdlike tail, the claws, these don’t do much to support the notion that the archaeopteryx could fly but then again it did have other modem birdlike features so it probably could rise up off the ground but only very awkwardly and it probably wasn’t too graceful once it got into the air. Actually though, as to whether the archaeopteryx could fly, we don’t really have any conclusive evidence one way or the other.

Student: So do you agree with the paleontologists professor, or the ornithologists?

Professor: Well, the most recent research is based on some fossils being found in China .It’s hardly complete but I find its conclusions really compelling.

Apparently, the features of the archaeopteryx may have evolved not for flight, but either for display, males using colorful features to attract a mate, or for insulation .And features are very useful for conserving body heat in cold temperatures.

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