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The Little Algae That Could
A reader writes "This NewsFactor Network article says scientists have discovered a genetic "missing link" that helps to explain how primordial pond scum evolved into the land plants that now cover the Earth. Their conclusion: A type of green algae is the closest living relative of the first land plants."
You can find the original, non-watered down story at Nature. Of course, you need a subscription :-)
Well... the news article misses the beat on a few things, including which journal it was published in (Science, not Nature). The term "missing link" is often bandied about in the news whenever the topic turns to ancestral organisms. That wasn't really what the paper was about. The real issue was that this algae appears to be the closest living relative of the land plants. For that reason, any characteristics it has in common with the land plants are most likely ones which were present in the common ancestor of all land plants. Being able to place the ancestor of the land plants between two "frames" this way (common characters of land plants AND characters of Charales algae) gives us a window onto what kind of organism the land plants are derived from. Here's a tiny quote from the original paper:
Identification of the Charales as the sister taxon to land plants with the Coleochaetales as sister to the Charales/land plant clade suggests that the common ancestor of land plants was a branched, filamentous organism with a haplontic life cycle and oogamous reproduction... Although it is tempting to envision the origin of land plants as having been from amorphous pond scum, these data indicate that the common ancestor of land plants and their closest algal relatives was a relatively complex organism.