I'm not a prophet, and I want to make it clear that this is an uninformed and partisan opinion. I'm basically an enthusiastic but not terribly knowledgeable fan of the Dallas Cowboys, and none of the NFL pundits I've read are going to say anything this strong.

But, I have to sound off about this Sunday's playoff game between the Cowboys and the Vikings: I think it's going to be Brett Favre's last game in the NFL. The last time he played a Wade Phillips defense, he was 38 years old. A corner blitz knocked the living legend out of the game in the second quarter, when a fourth-string cornerback named Nate Jones put his helmet on Favre's elbow. Aaron Rodgers came in to run the offense and sometime during that game probably convinced the coaching staff that he would be able to replace Favre in an outstanding effort that nearly brought Green Bay back in a game in which they were seriously undermanned on offense.

And, after that '07 season was over, as everyone knows, Favre hung it up. Sorta. Kinda. Well, all that was two jerseys, two comebacks and 26 months ago.

Favre is now, at 40 years and change, the oldest quarterback to start a playoff game. Ever.

A less accomplished fellow with a stronger grasp of their own mortality would probably tweak their game to reflect their oddysey as the last of their generation of football players. Not Brett Favre. He is still the same gunslinger who likes to make plays, throwing on the run to his right side, even into double or triple coverage.

In other words, he's a stubborn, but talented son of a gun. You couldn't play the way he's playing if you weren't both of those things. A guy with dramatically-reduced skills would've already lost his job. A guy who modified his game wouldn't have accumulated the kind of numbers (and attention) that Favre seems to crave. Favre has the job, and he has the numbers, and quite deservedly our attention. Bully for him, for not conceding anything to Father Time even though he's not getting any younger.

But, here's the thing. Wade Phillips hasn't gotten any younger, either, but he has always served up some of his best work at Favre's expense. (Exhibit A: 1998 Atlanta Falcons) He has a lot more to work with on the defensive side of the ball now than back in November of 'o7, particularly in the Cowboys' rebuilt secondary.

And, frankly, Phillips doesn't have to move and run an offense against his own defense. Brett Favre does.

I hope, really, that nothing bad happens to Brett Favre. I want to win, but I don't want anyone to get hurt. But the way I see it, this guy is going to get whacked. If the Cowboys can get to Favre, they will win. Pretty much everyone really understands that, except the strong-willed Favre. He's going to end up holding a football a bit too long trying to make a play, and the Cowboys pass rush is going to make him pay for it. That, more than anything else, is why I think the Vikings will come up short in the divisional playoff, and (expecting the costs to be dear) that is why I think Favre's career has one game left.

You can call me arrogant, but the way this Cowboys defense is playing, it's not that much of a stretch to see that they are going to get multiple shots at Favre's 40-year-old body. It doesn't take a degree in psychology to understand that a great competitor like Favre is going to hang on longer than he should in a game of this dimension, and that the likelihood of serious injury is magnified as a result.

The Vikings do have an equalizer, though: Adrian Peterson has the ability to take over the game not just as a runner, but as a receiving option. The Norsemen have got to hope that they are able to establish this aspect of their game early and often in the first half, and get a couple of scores on in the first quarter. This will help them dampen the Dallas pass rush, and reduce the chance of a corner blitz skewering their old field general.

But I wouldn't bet on it. The Dallas front four has shown they have the ability to pressure a QB without needing a lot of help from blitz packages, and they've been especially ferocious the last six weeks. And, the last seven weeks, 'AP' has not had the sort of signature performance required to balance the Vikings' aerial attack. Instead, time and again, Peterson's either been stuffed running inside (rather than to the perimeter), or when productive, his carries have been limited by the well-documented tendencies of his QB to audible pass plays. I

f you had asked me at mid-season which team was better, I would've said the Vikes hands-down, but a perfect storm is coming to the Metrodome or whatever they are calling their facility these days. No matter the outcome, this game is going to be hard to forget. If Favre can win, he will set another of those records he seems to excel at collecting: oldest QB to start and win a playoff game, for example.

But, I think it more likely that the Cowboys are going to be the villains in this playoff. Don't say I didn't tell you if it pans out that way.



A family member sends me a link to this news story about a marvelous creature, the sea slug Elysia chlorotica:

I know, it looks like a leaf. But, actually, its a mollusc, specifically a gastropod, like the snails and slugs you might find in your garden. This particular slug's green color is derived from the fact that it sucks up up intertidal algae as a food source and actually incorporates some of the captured chloroplasts into its own cells. The significance of the news item is that scientists from the University of South Florida have shown that the slug has acquired the genes to manufacture its own chlorophyll, a pigment required for photosynthesis. That is a little mind-blowing, and the best guess put forward to how this happened is a process (horizontal gene transfer) usually associated with bacteria.

Most of us have grown up knowing that plants do photosynthesis, and animals eat the plants. Plants are said to be autotrophs ('self-feeders') since they make their own food, while organisms like ourselves are described as heterotrophs ('other-feeders') since we eat the plants or some other creature higher up in the food chain based on the plants.

But the skimpy MSNBC article I was originally sent is a little breathless* when it describes the creature as 'half-plant, half-animal.' I (ahem) 'fished' around for other news coverage , and while this article is better on the science, it still uses the (misleading) 'part animal, part plant' tagline.

In the first place, algae are not plants, anymore than mushrooms are plants. While photosynthetic like plants (which are multicellular), algae as a group are simpler, the vast majority unicellular and found in aquatic environments. Algae are actually a very diverse group, more so than the plants, with many important biochemical differences, and phylogenetic studies reveals that the common ancestor of today's land plants and modern-day algae lived nearly 500 million years ago. Bottom line: algae are similar to plants in some ways, but different in others and they are not all that closely related.

In the second place, it would be just as clumsy to describe the sea slug Elysia chlorotica as 'half-animal, half-algae' . Elysia chlorotia is still a sea slug, it is still a mollusc, it is still 100 percent animal. How can I say that? Because, morphologically and behaviorally it is still defined in those terms: it is a heterotrophic, ingestive, predatory.

People will no doubt wonder if all these distinctions matter. After all, doesn't the sea slug have some algae genes? There is a subtle point that needs to be acknowledged, however. While properly speaking genes from algae could be called 'algae genes', there is nothing inherently 'algae-ish' about the genes. Genes are simply instructions to build proteins, and the fact that a sea slug appears to have acquired a recipe for building something exotic doesn't mean that it's now anything other than a sea slug.

After all, you and I both have fifty percent of the same genes as a banana. That doesn't make us 'half-person, half-plant'.

Now, some (often creationists) have suggested that the fact of horizontal gene transfer is a blow to the old 'tree of life' image in biology, that there might be something fundamentally wrong with the notion of common descent. Please. We can still draw phylogenetic trees, we just have to add some horizontal nodes to our branching diagrams:

All this does is establish another mechanism for the generation of genetic diversity in populations. If it is to be of value to any population, the incorporation of new genes must somehow enhance fitness. Natural selection will still be involved, and if the venerable image of a tree can not always be mapped exclusively to "vertical" branches, oh well. Evolution still happens!

* There are lots and lots of organisms that are not plants, but can still photosynthesize or which have little photosynthesizers living in them. Euglenoids, for example, are well-known protists that swim, they eat other microorganisms, and turn sunlight into sugars.