Comments on: Life’s Modest Majesty

By: Greg Peterson

Greg Peterson — Wed, 09 Jul 2008 16:53:03 +0000

Are BEYOND evolutionary innovation’s outer limit, that should say.

OK, and I didn’t do a great job with the whole comment. What I’m trying to get at is, I picture the first air-breathing tetrapod and there’s all this LAND with all these various terrains and climates and such, and evolution can go off wildly in many directions. But once those niches are filled, I would think that the capacity for radical innovation would taper severely. Could that not be the limiting factor?

By: Greg Peterson

Greg Peterson — Wed, 09 Jul 2008 16:50:08 +0000

Would we not expect an explosion of diversity shortly after a new phylum emerged as new niches are exploited and filled, and a slow-down in diversity once available niches are evolutionary innovation’s outer limit?

By: amphiox

amphiox — Wed, 09 Jul 2008 02:48:52 +0000

WARNING: using loupes to pick at even smaller nits. . . .

one that claimed the dinosaurs

and

this myth that dinosaurs went extinct at the end of the Cretaceous

That event certainly claimed dinosaurs. Lots of them went extinct. A vast majority, I would presume. Mr. Zimmer did not write “all” dinosaurs.

By: Carl Zimmer

Carl Zimmer — Tue, 08 Jul 2008 01:43:01 +0000

I let that one slip by me. When I say dinosaurs, I mean, of course, non-avian dinosaurs.

By: Jerry Dl. Harris

Jerry Dl. Harris — Tue, 08 Jul 2008 00:57:48 +0000

WARNING: nit-picking ahead…

Some of the sexiest mass extinctions, like the one that claimed the dinosaurs 65 million years ago

Shame on you, Mr. Zimmer! As one of the best and a leading science journalists out there (and, might I add, one I respect a great deal), I find it surprising that you would perpetuate this long-standing myth about the Cretaceous-Paleogene extinction event! Surely you know that birds are extant dinosaurs (birds evolved from theropod dinosaurs and therefore are theropod dinosaurs, just as humans evolved from primates and therefore are primates), so the quoted sentence is patently false as stated. Is it true that the end-Cretaceous extinction claimed most of the dinosaurs? Certainly. Is it still a “sexy” extinction event (in the sense of being evocative for the non-specialist and attracting lots of scientific attention)? Of course. But we’ve known for over 20 years now that dinosaurs did not go extinct at the end of the Cretaceous because some of them survived and even thrived in the Cenozoic and supercede mammals in terms of diversity today! Please…let’s kill this myth that dinosaurs went extinct at the end of the Cretaceous!

By: amphiox

amphiox — Mon, 07 Jul 2008 17:33:58 +0000

Hmm, this graph seems to contradict a claim I read in a book by Peter Ward (The Life and Death of Planet Earth, I think) that earth’s total bioproductivity had probably peaked during the Permain and has been dropping steadily since.

By: Phil Plait

Phil Plait — Sat, 05 Jul 2008 19:32:14 +0000

Interesting! The bin size is a bit too big to see any periodicity on a, say, 60 million year time scale. There’s a claim that there is a periodic drop in number of genera on that scale, possibly linked with the Sun’s orbit around the Milky Way. I explore this a bit in my upcoming book, and while it’s interesting, it’s still tentative.

By: llewelly

llewelly — Fri, 04 Jul 2008 21:29:42 +0000

Everyone interested in biological diversity should read this great article on still more evidence that a severe drop in diversity has already began.

By: David Bradley

David Bradley — Fri, 04 Jul 2008 07:38:18 +0000

Intriguing, yes…but greater diversity now than millions of years ago does not mean (as you know) that we have any excuse to ignore the destruction of ecosystems across the globe, with concomitant extinctions, that we carry out in the name of progress.

By: Jan-Maarten

Jan-Maarten — Fri, 04 Jul 2008 07:02:02 +0000

Fascinating! Looks like there’s a couple of sharp drops after gradual rises.. But what’s up with the gradual decline in the Carbonian?

By: Carl Zimmer

Carl Zimmer — Thu, 03 Jul 2008 22:51:35 +0000

Indeed. Fixed it. Thanks!

By: EastwoodDC

EastwoodDC — Thu, 03 Jul 2008 22:24:37 +0000

>Perhaps there isn’t enough energy to let evolution run wild. The energy that comes from the sun gets dissipated as it flows through complicated food webs, and so it can support lots of new genera.

Should that be “CAN’T support lots of new genera.”?
That would seem to be more in keeping with limited energy keeping the exponential growth in check.