LIFE × EVOLUTION

The First Flowers

~140 million years ago (origin debated)

Phanerozoic · Mesozoic · Cretaceous

A flower does two things at once: it locks the seed inside a container, and it advertises to an animal. Plants that do both are the angiosperms, and when they began is the longest-running argument in botany. Unmistakable fossils start about 135 million years ago; a count of fifteen thousand fossil occurrences across two hundred families puts several of those families in the Jurassic, and the gene trees go further back still, to the end of the Triassic. Whatever the origin, the spread is Cretaceous: lineages pile up between 125 and 72 million years ago.

Why it matters

Three quarters of living plant species are flowering plants, and so is nearly everything on a dinner plate. They also rebuilt the food webs of the land from the bottom: more insects, and then more of the birds and mammals that live on insects.

Dating & uncertaintyDisputed

Unequivocal angiosperm fossils begin in the Early Cretaceous, near 135 to 125 Ma, while analyses that correct for incomplete sampling, and most molecular clocks, place the origin in the Jurassic or earlier. The mismatch is one of the oldest arguments in palaeobotany.

Sources

1. Sun et al. (2002), Science · Archaefructaceae, a new basal angiosperm family
2. Silvestro et al. (2021), Nature Ecology & Evolution · Fossil data support a pre-Cretaceous origin of flowering plants
3. Li et al. (2019), Nature Plants · Origin of angiosperms and the puzzle of the Jurassic gap
4. Magallón et al. (2015), New Phytologist · A metacalibrated time-tree documents the early rise of flowering plant phylogenetic diversity

Earth history as one day

23:15:3544 min 24 s before midnight

if Earth’s 4.54 billion years were compressed into a single day