Hi everyone, I´m finally back both physically and mentally from my holiday to NYC(where I met some fabulous people by the way) and I´ll get right down to business.
I´ll start with this large little item.
Sometimes really weird, fun, unexpected things turn up out of nowhere.
These amoeba may change the way we view evolutionary history!
In 2008, some researchers looking for deepwater fish found some large lumps of mud-covered stuff on the ocean floor. Behind each of them it looked like there was a track, left by some sort of motion, like they´d been rolling around, and some seemed to have rolled upwards. Some were about 50 centimeters long, and the organisms were the size of grapes. Back in the lab, it turned out that these grape-sized thingies were actually giant one-celled protozoa(early animals that eat other organisms)!
(These balls of weirdness were first discovered in 2000, but at that site there were no tracks, which turned out to be very important.)
Previously it has never been known that single-celled creatures can make tracks from motion.
The tracks are marked in the middle with a narrow ridge, and they look very similar to some fossilized tracks dated to be about 1.8 million years old. These tracks have been taken as a sign of possible multicellularity, or even that there were animals that were bilaterally symmetrical at this early stage. However,most other lines of evidence point to a development of multicellularity at about 600 mya. These tracks were then just about the only indication of multicellularity at such an early time.
This is interesting because there are differing ideas about how long of a warm-up there has been for multicellular diversification before the Cambrian explosion at about 542 mya. With the discovery that the tracks were likely made by single-celled protozoa, this removes our earliest signs of multicellularity, leaving us with pretty good consensus on multicellularity developing at around 700-600 mya.
This article contains a somewhat unfortunate quote from one of the discoverers of the tracks. He´s talking about how this discovery removes the long, slow start leading to the Cambrian explosion where we relatively suddenly see lots of new animals, major groups and diversification in the fossil record.
"It wasn't a gradual development of complexity," Matz said. "Instead these things suddenly seemed to burst out of a magic box".
Bah! I just hate it when scientists bring up magic in a sentence like this. You just know the creationists will be jumping all over it, claiming that biologists agree that there is too much weirdness in nature all to be explained by science.
I couldn´t disagree more. I wish he would have turned the phrase in a different direction.
I think it´s amazing and wonderful and that this discovery really demonstrates the power of natural processes and that nature can make huge changes come about in a relatively short period!
Drawing supernatural force into this is unjustified, unnecessary and a bit short-sighted.