National Geographic reported this week on the discovery, in Namibia, of the oldest fossils yet found of a multicellular animal.
At 760 million years old, Otavia antiqua is described as a sponge-like multicellular organism about the size of a grain of rice. These organisms were incredibly hardy, remaining relatively unchanged for 200 million years, and surviving at least two ‘Snowball Earth‘ events.
The previous oldest organism was also a sponge, and had been dated to 650 million years.
These organisms represent the earliest ancestors of all the multicellular organisms which have arisen since, from Dinosaurs to Humans.
Image courtesy Anthony Prave, University of St. Andrews
The BBC reports on research into a species of sea grass found in the Mediterranean Sea that may be tens of thousands of years old.
This grass, Posidonia oceanica, reproduces in such a way as to avoid the normal problems with cloning that introduce so-called ‘copy errors’ resulting in mutations which would otherwise limit the survivability of successive generations. By combining both asexual and sexual reproduction Posidonia has been able to grow in colonies up to 15km across on the sea floor for tens of thousands of years.
This research sheds light on how an organism can avoid damaging mutations from one generation to the next while adapting to changing environmental conditions.
I went a little bit link crazy a couple of days ago, after I listened to a lecture on stem cells (sometimes called progenitor cells) and cloning. Much of what the presenter discussed sounded like science fiction: healing spinal injuries, reversing retinal damage, replacing damaged cardiac or brain tissue following heart attacks or strokes…
But it turns out this is all current science. Happening right now. Mostly in trials using mice and the like, but in a few noteworthy cases, in actual clinical human trials.
Anyway, if you are comfortable with the basics of embryology and cloning, you might find the links interesting. Otherwise, read up on the basics of stem cells – what they are, how they were found, what they can do – and then get ready to have your mind blown away.
Spinal Cord Injury – Dana Foundation
Regenerative benefit demonstrated in spinal cord injury
Reconstructing neural circuits using transplanted neural stem cells
Retina created from embryonic stem cells
Repairing the optic nerve using stem cells
This week sees the observation of farming by Dictyostelium discoideum, a species of amoeba.
This amoeba is well-known for another curious behaviour: colonies of these organisms will form a fruiting body to produce spores when conditions become hostile. The spores are released to spread the organisms’ chances of survival further afield. In this instance, the amoeba was shown to ‘farm’ the bacteria that constitutes their food. This is agriculture! By microbes!!! Amazing.
More explanation at the BBC Science & Tech site.
I’m embarrassed at how late to the party I am with this, but PZ Myers has a great review of Richard Dawkin’s new book on what I’m going to take to calling the Fact of Evolution.
Have a read here.
This is slightly older news, but I’ve realised that the recently opened Doomsday Global Seed Vault which several folks have been banging on about is in the same general area as the monster-sized pliosaur find: the Svalbard Archipelago!
The Doomsday vault is a terrific idea. Similar to the Kew Millenium Seed Bank opened in London in 2000, its purpose is to safeguard existing plant genetic diversity against accidental loss or mismanagement.
The non-scientific media have been quick to position this as a doomsday scenario – as a result of nuclear war or cosmic cataclysm – and commentators have made connections with increasingly popular genetically modified cropping. However, this facility is far more likely to act as insurance against losing species of plants in a more insidious way: by people’s apathy about conservation.