winners and losers

Folks at UCLA have created a list of evolutionary winners and losers. They've based this list on a species' ability to diversify over time. At the top of the winners list are birds (with 9,000 species) and mammals (with 5,400 species). Compare that speciation with big fat losers like crocodiles and alligators. Crocs and gators have been evolving for 250 million years and have exactly 23 species to show for it.

One particular loser highlighted in the article is the tuatara, a native to New Zealand.


It looks like a lizard, but they claim it's more closely related to snakes. Believe what you will. Whatever its family tree, the poor little guys have only diversified to two species. In that same amount of time, we've been graced with over 8,000 different species of snakes and lizards. You may be like me and say, "Summin' ain't right... how come?" Even those who actually study this stuff for a living are mystified. They are offering a free mosquito teen-repellent device to anyone who can provide an answer.
So like most scientific studies, we're left still losing sleep over this. That's why I stick by my guns and say: if you throw "evolution" out the window, you don't NEED answers. That simple.

In breaking news, here is the latest addition to the list of winners:


Dave, the kitten that survived being shot with a crossbow.

If you want to read the actual article, go ahead.


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It looks like a lizard, but they claim it's more closely related to snakes.

What? That's not right. Snakes are nested within lizards and the tuataras are basal to the whole squamate clade.

By Sven DIMilo (not verified) on 03 Aug 2009 #permalink

Well... from my understanding, while they do belong to the same order, they're obviously of different suborders. And yeah, snakes did evolve from lizards, but they're two very different types of reptiles with distinguishing characteristics that define them both. I think the article is claiming that given the differences between lizards and snakes, the tuatara sticks closer to the snake side of the reptilian evolutionary tree.
Any one else want to chime in?

Sven is right. Snakes (in spite of their unique anatomy) and lizards are more closely related to each other than either group are to tuataras. In fact, snakes are really just highly specialized lizards (or, in the parlance of Alfaro et al. "non-gekkonid squamates", which is incidentally a paraphyletic grouping but, eh, who's counting).

Not that you would know it from the Alfaro paper, but both crocodylians and sphenodontians were far, far more diverse in the past than they are today. Extinction's a bitch.

I must dissent about... Eh...
AWWWW! Poor kitteh! :3

By Luis Daniel (not verified) on 03 Aug 2009 #permalink

So many things wrong...
but that's surely not a cross bow bolt, it's way too thin, and looks like a standard arrow for standard style bows. :P

Rosel: It's a crossbow bolt. Look at the end ... the style of nock is the clue.

I hunt ( deer and elk, not pets ) with one ... the bolts are starting to look a lot like arrows these days.

By Kristopher (not verified) on 04 Aug 2009 #permalink

Birds? Mammals? Winners? Who are these guys kidding? There are over 10,000 species in just the grass family; the orchid family is even more speciose. And then there are the Coleopterans. Ah, but the fascination with the depauperate vertebrates continues.

When you're already perfect, who needs to diversify? And even by that measure, DrA is right, these counts are all dwarfed by the number of beetles species out there.

I think UCLA was paid off to hide who the REAL winners are...

For a slightly more accurate assessment of evolutionary "winners" and "losers," might we want to know how long birds and mammals have managed to remain on the scene?

Yes. Snakes are limbless lizards, phylogentically. Tuatara are the last living remnants of Sphenodontia, the extant sister group of Squamata (the clade comprising lizards -- including snakes -- and the so-called "worm lizards").

In my book, if you are not extinct, you are at least a runner-up.

this only confirms my suspicion that one needs to use the proper yew Welsh-made longbow on kittehs, crossbows are not as effective from a distance (not mentioning their slow fire rate).

Posed Kitty with arrow???

I also don't believe that level of diversification is equated with success. If you've managed to survive, then you're successful. If you can do it without having to change, then good for you.

Neil is right - there were possibly 100s of species of Sphenodontids back in the day, and they ranged all across Europe and the Americas. They just all went extinct, except for the tuatara. So saying the tuatara has only diversified into 2 species (and actually it should only be one), is a bit like saying homo sapiens is a loser for only diversifying into one species.

That poor kitten it defentaly has been shot some people say that the bow looks fake but hey just because you've seen a cross bow doesnt mean that the one that you saw was the only one in exitence!!!!!!

By hella baloh (not verified) on 16 Jun 2010 #permalink