The Earliest Crown Mammals
The crown group mammals, sometimes called 'true mammals', are the extant mammals and their relatives back to their last common ancestor. This part of the story introduces new complications, since the crown group are the only group that still has living members, enabling both anatomical and DNA analysis:
- One has to distinguish between extinct groups and those that have living representatives.
- One often feels compelled to try to explain the evolution of features that do not appear in fossils. This endeavor often involves Molecular phylogenetics, a technique that has become popular since the mid-1980s, but is still often controversial because of its assumptions, especially about the reliability of the molecular clock.
Read more about this topic: Evolution Of Mammals
Famous quotes containing the words earliest and/or crown:
“Late in the afternoon we passed a man on the shore fishing with a long birch pole.... The characteristics and pursuits of various ages and races of men are always existing in epitome in every neighborhood. The pleasures of my earliest youth have become the inheritance of other men. This man is still a fisher, and belongs to an era in which I myself have lived.”
—Henry David Thoreau (1817–1862)
“I often used to think myself in the case of the fox-hunter, who, when he had toiled and sweated all day in the chase as if some unheard-of blessing was to crown his success, finds at last all he has got by his labor is a stinking nauseous animal. But my condition was yet worse than his; for he leaves the loathsome wretch to be torn by his hounds, whilst I was obliged to fondle mine, and meanly pretend him to be the object of my love.”
—Sarah Fielding (1710–1768)