Kids underfoot? Are they pestering you for entertainment? Tell them to go look up dinosaurs in Dinobase, and to come back when they’ve got them all memorized. I remember as a kid it was easy to wow the grownups by memorizing a few dozen genera, but now … whoa. There’s more minutia there than you’ll find in packs of baseball cards, that’s for sure.
I’ve been looking forward to seeing these little jewels in print since I saw Kuratani talk about them at the SICB meetings in January. Hagfish are wonderfully slimy jawless chordates that have been difficult to raise in the lab—although if you poke a whale corpse rotting in the cold deeps you’ll find them swarming everywhere. The Kuratani lab has managed to keep animals of the species Eptatretus burgeri alive and healthy in a lab aquarium maintained at cold temperatures (16°C), and has even had success in breeding them. That object to the right is a single hagfish egg, brown and leathery-shelled and surprisingly big—it’s an inch and a half long!
They collected 92 eggs, and then another limitation emerged: it took 5-7 months for embryos to develop in a small number of the eggs. Hagfish aren’t going to be your typical fast-developing model system, I’m afraid, but they are extraordinarily cool animals, and it’s good to see work beginning on them.
NOVA is going to be showing a program on the cuttlefish Tuesday evening, 3 April — it’s called Kings of Camouflage, and the website for it is also very well done, with nice illustrations of anatomy and behavior, and one excellent clip of color changes. I’m definitely going to tune in, check it out!
I must disagree with Larry Moran, who accuses the field of evo-devo of animal chauvinism — not that it isn’t more or less true that we do tend to focus on metazoans, but I disagree with an implication that this is a bad thing or that it is a barrier to respectability. Larry says we need to cover the other four kingdoms of life in greater breadth, which I agree is a fine idea. I would like to have a complete description of the genome of every species on earth, a thorough catalog of every epistatic interaction between those genes during development, a hundred labs working on each species, and a massive collection of papers for each one documenting every step and every protein and every variation in their development. I would like it tomorrow.
I think we all agree that that would be impractical. The question is how we will focus our research to maximize our use of limited resources, and get us useful answers that will lead us in productive directions. Larry is advocating maximizing our phyletic breadth by following organisms representative of the greatest amount of diversity. He is proposing this in opposition to the proposal from Jenner and Wills, who suggest a different strategy — and I find myself agreeing more with Jenner and Wills than with Moran.
The mammalian tree is rooted deeply and branched early!
That’s the message of a new paper in Nature that compiled sequence data from 4,510 mammalian species (out of 4,554) to assembly that lovely diagram above. Challenging the ‘conventional wisdom’ that mammalian diversity is the product of an opportunistic radiation of species after the dinosaurs were wiped out at the end of the Cretaceous 65 million years ago, the authors instead identified two broad periods of evolutionary expansion among the mammals: an early event 100-85 million years ago when the extant orders first appeared, and a radiation of modern families in the late Eocene/Miocene. A key point is that there is no change in rates of taxon formation across the Cretaceous/Tertiary (K/T) boundary—mammalian diversity was rich before the dinosaurs disappeared.
It’s a b i g picture, slowly scrolling by, of a full-sized blue whale. Load it up and just let the whale swim past your window…it’ll take a while.
(via inkycircus)
This evening, I caught most of some episodes of this series the Discovery Channel is airing, Planet Earth, which was advertised here for a while. It wasn’t bad. It had some spectacular photography, did a great job of displaying a wide range of environments, and showed off some of the amazing abilities of animals very well. There were a few things that irritated me, though (I admit it, I criticize everything).
The biggest problem? It’s a show for people with short attention spans. We got brief vignettes of a few minutes—you’d just be getting into the pumas and alpacas in Patagonia, and zip, we’re off to grizzly bears in the Rockies. It was popcorn biology, crunch crunch crunch, you’ve snarfed down a whole bag a few kernels at a time.
That quick glimpse of each biome also meant the focus was entirely on the biggest, most distinctive organisms in the environment, the ol’ charismatic megafauna problem of nature documentaries. For instance, several of the scenes featured whale sharks or dolphins or sailfish chowing down on these great schools of generically named “bait fish”…but hey, wait a minute, aren’t these “bait fish” a rather critical component of the ecosystem? Why not tell us more about them? Treating them as convenient clouds of meat for bigger predators didn’t seem to do them justice.
Still, it was worth watching, and maybe younger kids would have an easier time getting into it. After a few hours exposure, I was feeling a bit whipsawed by the too frequent changes in subject.
Here’s a picture to make you feel relatively fortunate, from the April 2007 issue of Natural History:
Naked mole rats are odd little mammals in which only the queen of the colony gets to breed. The point of this picture is that even when not near the end of their term of pregnancy, they are recognizably distinct from other rats in the colony — they tend to be much longer. The reason is that the hormones during pregnancy, and probably also the physical stresses on their body, induces the lumbar vertebrae to actually grow longer. Humans, fortunately, do not grow a couple of inches vertically with each child.
