This site is not maintained. Click here for the new website of Richard Dawkins.

New science: ancient eukaryotes and altruistic ants

Original article

Eukaryotes may be way older than we think. A paper in this week’s Nature (with Roger Buick’s News and Views summary here) reports the finding of eukaryote-like microfossils in South American rocks dated at 3.2 billion years b.p. (before the present). Yes, that’s right: 3.2 billion. Up to now, the oldest known fossils of eukaryotic cells (i.e., “true” cells with chromosomes and a nucleus) dated 1.8 billion years b.p., so it was assumed that it took a long time to evolve the eukaryotic cell from the bacterial cell (bacterial microfossils first appear about 3.5 billion years ago). This new finding, if true, pushes back the origin of true cells very close to the origin of prokaryotic cells themselves, so it may not have been that difficult to evolve a true cell.

The “acritarchs” found by Javaux et al. may be eukaryotes, but there’s some doubt. They are large (up to 0.3 mm, which might be visible to the naked eye), but some bacteria are also that large. And while they have cell walls (see Fig. 1), a structure found in eukaryotes but not prokaryotes, these are nowhere near as complex as those seen in much younger true eukaryotic fossils. On the other side, as reported by Roger Buick in his News & Views on this paper, sterane “biomarker” molecules (organic molecules that are uniquely produced by eukaryotes) have been found in deposits that are 2.45 billion years old, suggesting that maybe Javaux et al. are right.

We’ll have to wait and see about this, but the Javaux et al. paper suggests that we may have to radically rethink our views about the origin of cells. They might have appeared 1.4 billion years earlier than we thought! In the meantime, I’m revising my lecture notes.
...
Continue reading

TAGGED: BIOLOGY, EVOLUTION, PALEONTOLOGY


RELATED CONTENT

Planet of the apes

Stephen Cave - Financial Times Comments

What we really know about our evolutionary past – and what we don’t

WALK DARWIN’S TREE OF LIFE ~ 25 - 26...

- - Ancestors Trail Walk Comments

WALK DARWIN’S TREE OF LIFE ~ 26 AUGUST 2012 - event begins on Saturday 25 August

Astrophysicists simulate 14 billion...

Liat Clark - Wired.co.uk Comments

Astrophysicists simulate 14 billion years of cosmic evolution in high resolution

Study casts doubt on human-Neanderthal...

Alok Jha - The Guardian Comments

Cambridge scientists claim DNA overlap between Neanderthals and modern humans is a remnant of a common ancestor

Why do organisms build tissues they...

- - Science Blog Comments

Why, after millions of years of evolution, do organisms build structures that seemingly serve no purpose?

New flat-faced human species possibly...

Charles Choi - CBS News Comments

Four decades ago, in 1972, the Koobi Fora Research Project discovered the enigmatic fossilized skull known as KNM-ER 1470 which ignited a now long-standing debate about how many different species of early Homos existed.

MORE

MORE BY JERRY COYNE

James Shapiro goes after natural...

Jerry Coyne - Why Evolution Is True Comments

James Shapiro goes after natural selection again (twice) on HuffPo

What’s the problem with unguided...

Jerry Coyne - Why Evolution Is True Comments

What’s the problem with unguided evolution?

The demise of group selection

Jerry Coyne - Why Evolution Is True Comments

The demise of group selection

With a note form Richard

Higgs Boson found?

Jerry Coyne - Why Evolution Is True Comments

Higgs Boson found?

Science, Religion and Society: The...

Jerry Coyne - Evolution 10 Comments

Jerry Coyne's paper on the relationship between acceptance of evolution, religion, and societal health, available for free download.

Mencken week: Day 2

Jerry Coyne - Why Evolution Is True 11 Comments

MORE

Comments

Comment RSS Feed

Please sign in or register to comment