Living fossil is an informal term for any living species (or clade) of organism which appears to be the same as a species otherwise only known from fossils and which has no close living relatives. These species have all survived major extinction events, and generally retain low taxonomic diversities. A species which successfully radiates (forming many new species after a possible genetic bottleneck) has become too successful to be considered a "living fossil".
Famous quotes containing the words living and/or fossil:
“As for conforming outwardly, and living your own life inwardly, I do not think much of that. Let not your right hand know what your left hand does in that line of business. It will prove a failure.... It is a greater strain than any soul can long endure. When you get God to pulling one way, and the devil the other, each having his feet well braced,—to say nothing of the conscience sawing transversely,—almost any timber will give way.”
—Henry David Thoreau (1817–1862)
“The earth is not a mere fragment of dead history, stratum upon stratum like the leaves of a book, to be studied by geologists and antiquaries chiefly, but living poetry like the leaves of a tree, which precede flowers and fruit,—not a fossil earth, but a living earth; compared with whose great central life all animal and vegetable life is merely parasitic.”
—Henry David Thoreau (1817–1862)