 |
| Twisted Tree of Life |
Every once in a while I give out an award here for bad discussions of evolution in the media or scientific publications. I call this the “Twisted Tree of Life Award.” And here is a doozy. It comes from a recent paper in Science: The Shifting Balance of Diversity Among Major Marine Animal Groups — Alroy 329 (5996): 1191 — Science
The fossil record demonstrates that each major taxonomic group has a consistent net rate of diversification and a limit to its species richness. It has been thought that long-term changes in the dominance of major taxonomic groups can be predicted from these characteristics. However, new analyses show that diversity limits may rise or fall in response to adaptive radiations or extinctions. These changes are idiosyncratic and occur at different times in each taxa. For example, the end-Permian mass extinction permanently reduced the diversity of important, previously dominant groups such as brachiopods and crinoids. The current global crisis may therefore permanently alter the biosphere’s taxonomic composition by changing the rules of evolution.
- Twisted Tree of Life Award #7: NPR on the Evolution of Crying
- Twisted tree of life award #6: Scientific American Origins piece for dissing microbes
- Twisted tree of life award #5: Nicholas Wade & use of higher, lower, ladders, etc
- Twisted Tree of Life Award #4: Hoxful Monsters Blog on “Primitive” Animals
- Twisted Tree of Life Award #3: The Columbus Dispatch on Ancient Bacteria
- Twisted Tree of Life Award #2: Science Friday on the Five Kingdoms
- Twisted Tree of Life Award #1: Salk Institute Press Release on Kinases
Share this:
Jonathan Eisen's Lab 
What is basically meant by this sort of statement (when used by people like John Alroy, David Jablonski, Charles Marshall, etc.) is that a bunch of groups (say, families) will be observed to each have their own quite constant diversification rate (a result of their rates of production and loss of new species or genera), which might be constant over say 100+ million years.
Then a mass extinction event will happen, and suddenly many of these groups will exhibit some step change in these rates. The result is that new groups become dominant etc.
IIRC Alroy showed that models with these step changes in rates are often preferred to constant-rate models using e.g. AIC.
Whether or not “new rules of evolution” rhetoric is warranted is debatable I guess, but it is interesting.
LikeLike
This is an example of the increasing tendency to cap off a perfectly good piece of science by eco-political statements, which sound great but have no validity except as sound-bites…. I wont exactly say “crisis, what crisis?” but it's a totally anthropocentric term. Were the previous extinction events crises? well not for us, since we are here…
above all else this reflects the fact that we should actually be reflecting on biodiversity – as an integrated hierarchical concept of genetic, species and ecosystem diversity – to try and understand the earth system, what we as one species are doing to it, and how we may need to change, or not , as the case may be.
as for your rules comment – well again as a species we seem to like (or rebel against) rules – i wont comment further!
thanks for starting my Sunday off in an interesting way!
LikeLike
NickM – yes – I see your point about what they might have been trying to say. But that abstract seems like a press release more than an abstract. The rules of evolution do not change. The PATTERNs may change and some groups may shift from one pattern to another, but I see no evidence the rules even remotely changed.
LikeLike
It seems reasonable that the author simply didn't consider how this comment could be interpreted by readers. Changing the rules of evolution for species at this moment and time makes sense (because we are, seen any dogs lately? LOL); but changing the rules of physics that govern evolutionary changes does not. He probably deserves a Bulwer–Lytton award more than a twisted tree award.
LikeLike
It seems reasonable that the author simply didn't consider how this comment could be interpreted by readers. Changing the rules of evolution for species at this moment and time makes sense (because we are, seen any dogs lately? LOL); but changing the rules of physics that govern evolutionary changes does not. He probably deserves a Bulwer–Lytton award more than a twisted tree award.
LikeLike
Still no0t buying it Runkinatiaaar. Dogs certainly have undergone some unusual evolution since they partnered up with humans. But the RULES of evolution have been the same – it is just the parameters that have changes. Subtle point to some maybe. But claiming ones own research shows how the rules of evolution have changed is a bit much for me. May have been accidental but it was in the abstract and I think worth pointing out to people out there that the rules really do not change …
LikeLike
Perhaps the initials instead of given names promotes gender equality. I know of multiple female scientists who publish only under initials for fear of bias against them if they used their given names.
LikeLike
I'm more bothered by the “each taxa” than anything else. It should be “each taxon”.
LikeLike