The De-Evolution of the Ocean

An anonymous reader writes to mention an LA Times article entitled 'A Primeval Tide of Toxins.' The article looks at changing conditions in the world's oceans, and the resulting explosion in the growth of algae, jellyfish, and other primitive lifeforms. From the article: "In many places -- the atolls of the Pacific, the shrimp beds of the Eastern Seaboard, the fjords of Norway -- some of the most advanced forms of ocean life are struggling to survive while the most primitive are thriving and spreading. Fish, corals and marine mammals are dying while algae, bacteria and jellyfish are growing unchecked. Where this pattern is most pronounced, scientists evoke a scenario of evolution running in reverse, returning to the primeval seas of hundreds of millions of years ago. Jeremy B.C. Jackson, a marine ecologist and paleontologist at the Scripps Institution of Oceanography in La Jolla, says we are witnessing 'the rise of slime.'" The article is parting of a just-beginning series on our changing world called Altered Oceans.

Comments

"DE"-evolution?

[Sebastopol]

Why is this devolution? It is simply selection pressure: the higher life forms are pressured into extinction, and the jellyfish and algae go back to evolving: one taxonomy branch is pruned so that another may try. That IS evolution (well, a big hoerkin' chunk of it).

Re:"DE"-evolution?

[JDevers]

Exactly. Why does everyone think that evolution only leads to more and more complex life forms? Evolution is simply the never ending meat grinder getting the most out of the available resources. More often than not simple life forms are actually favored, which is why we live in a world with a thousand species of bacteria for every "higher" life form and a few billion individual bacteria for every "higher" life form.

We (meaning animals) are almost an anomaly, not the rule. Anyway, as you said, as the environment changes so do the life forms that thrive in it. The very small are generally more able to cope with changing environments so they definitely win out in the short term.

Re:"DE"-evolution?

[lubricated]

well, I'm a biology grad.

In general during extinctions it is the specialists that do poorly and the generalists that do well. The opposite is true other times.

Re:"DE"-evolution?

[dan828]

Evolution is neither good nor bad, it is a description of what happens. It's kind of like calling gravity or relativity good or bad. There also is no such thing as "de-evolution." Evolution is the change of allele frequencies within a population over time due to differential reproductive success. If this results in a "simpler" form of organism or the extinction of the species all together, it's still evolution. Of the five great extinctions to hit the earth, none of them caused any "de-evolution," they just killed off a good portion of extant species and left a lot a niches open for the survivors to exploit. We might be at the begining of the next great extinction event (though I doubt it'll get to that point, as I think we'll clean up our act before it happens).

Re:"DE"-evolution?

[Michael Woodhams]

That was pretty much my thought when I read the story.

Bacteria are no less evolved than us. They've had the same 3-4 billion years, with more intense selection pressure* and much shorter generation times. They are exceedingly well optimised, and are the dominant branch of life on Earth.

* The larger a population, the more effective evolution is. This is standard nearly-neutral population genetics, demonstrated by Kimura.

Remember those museum displays labeled "Age of bacteria", "Age of Fish", "Age of Amphibians", "Age of Dinosaurs", "Age of Mammals"? They should have read "Age of Bacteria", "Age of Bacteria (plus a few multicellular marine organisms)", "Age of Bacteria (plus a few multicellular marine and land organisms)". Bacteria dominated the past, they dominate the present, and will be thriving when vertebrates are extinct.

Consider (as is commonly done) the history of life on Earth as a day (but ending with the end of life on Earth, rather than ending with today.) The Earth will be sterilised by the red-giant phase of the sun, in about 5 billion years. Taking life as starting 3 billion years ago, the Age of Bacteria lasts 8 billion years, and on our 24 hour time scale, that means it is now about 9am.

Cue music from "Hair":

This is mid-morning of the Age of Bacteria
The Age of Bactera
Bacteria! Bacteria!

Evolution doesn't have a direction

[PIPBoy3000]

It's funny when people claim that things are evolving into "higher" or "lower" forms, as if people are the obvious pinnacle of the process.

What's happening is that the rate of change in the environment is faster than many species can keep up. When you have 10,000 individuals in a population and they breed every 5 years, they can only "absorb" so much change. When you have a species that has billions of individuals and reproduce every 20 minutes, they can take massive environmental change and thrive in it.

The genetic diversity in the bigger population is vast and there's bound to be some individuals with higher tolerance of whatever the change is, be it increased temperatures, environmental toxins, or loss of food supplies. If one individual has the gene that boosts survival, it can propagate through the species very rapidly due to short lifespans.

Think of the human species as the biological equivalent as a comet hitting the earth and you've got it about right.

Re:Seems reasonable....

[timeOday]

Of course it is reasonable. Of course it is cause and effect. The question is whether we want to keep causing these effects. I for one would rather not leave the world to mold and cockroaches, even if they are superior in the darwinist sense of adapting to environmental devastation. Let's think deeply about this for a moment... 1) pollution is bad for complex, "highly-evolved" organisms; 2) people are such organisms; 3) you and I are people; 4) do you get it yet?

Well, sure . . .

[StefanJ]

. . . but if you rewind the VCR of evolution and let it play again, the show won't be the same.

It could tens of thousands of years for all the niches to re-fill. And because ecological niches are defined in large part by what life is already around, the new species that arise won't be the same as the ones we are used too and benefit from.

We could end up with an ocean without fish worth eating. They could be bony or greasy or, like a lot of fish species, poisonous.

And the human survivors living in the depleted, impoverished ecosystems we leave behind will utterly despise us for our careless, irresponsible, wasteful ways.

Re:Start of the next version of earth biology?

[exp(pi*sqrt(163))]

How come this pseudo-scientific babble was modded +5 interesting? Sure, the concept of life on a planet carrying out a "biological reset" might be a great concept for a science fantasy TV series like Star Trek, but it has no place in any kind of discussion of what might actually be happening on Earth right now. This kind of teleologico-evolutionary raving is no better than the kind of nonsense spouted by Creationists and is a nice example of how many people blindly subscribe to evolutionary theory as a kind of religion without having the faintest clue of what it's actually about. Of course it's not surprising that some people hold such views, but it is mildly shocking that such views get modded to the highest level of interest on /.

??? That's nonsense.

[porcupine8]

Evolution can't "run in reverse." Evolution doesn't have a goal or a direction. Natural selection says that whatever organism is best adapted to a particular environment/nice will reproduce more. It doesn't say that that organism must be more "advanced" or complex than the ones that were in the niche before. Less complex organisms are better able to adapt to the changes happening in these particular environments. Maybe they'll get some new adaptations eventually that lead to their becoming more complex. Maybe not. Maybe the environment will change again to favor the more complex creatures. Maybe not. But it's certainly not running "in reverse."

Re:??? That's nonsense.

[porcupine8]

But the problem is, people with less science background read things like that and get the idea that that IS how evolution works. I went to a church a couple of weeks ago and the pastor was giving an anti-evolution sermon (not going back there) - and he was using arguments like "evolution claims that if we wait long enough, eventually humanity will evolve into perfection" (with the further argument that only God is perfect, so evolution is wrong). Which is patently untrue, but if the general media keeps churning out things like this it's very easy to see how people get that idea.

It's not even a useful metaphor. It's more of an attempt at sensationalism.