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The Cretaceous Period was an important time for life on Earth. The Age of Reptiles was in full swing,
and dinosaurs were more diverse, more fierce, and more strange than ever.
But something else was happening under the feet of the terrible lizards. For the first time in history, there were flowers.
The fossil record of flowering plants goes back a long way--
about 125 million years, which is what I like to call a very long time
But in the big picture of evolution, flowers are relatively late bloomers.
Plants themselves make up a huge branch of the tree of life.
including everything from the moss you find on rocks to the towering redwoods.
But the thing is, before the Cretaceous, Earth’s landscapes looked very different.
If you could go back about 150 million years, past the Cretaceous to the Jurassic Period,
you'd see plants that probably looked familiar but still the picture would seem a little incomplete.
You'd find things like ferns--low-growing water-loving plants that are still around today
-you can probably find one at your nearest doctor's waiting room-
And there were lots of conifers--evergreen plants that typically bear cones like today's pines, firs, and spruces.
And then there were the cycads--seed bearing plants with tough spiky trunks and green fronds on top.
If you wanted to landscape your own Jurassic Park, these are the plants you would need
And what allowed ferns, conifers, and cycads to conquer the land was the way they reproduced.
Ferns, for example, reproduce from spores and need damp environments for their reproductive cells to reach each other.
Cycads have cones with seeds that are directly fertilized by pollen.
And for conifers, much of the hard work of fertilization is done by the wind,
which carries pollen from the male cones to the female cones.
But after the Jurassic gave way to the early days of the Cretaceous, a new form of plant emerged.
About 125 million years ago,
in a little pond in what’s now northeastern China, one of the first flowers bloomed.
Paleontologists have called the fossil of this primordial plant Archaefructus liaoningensis.
It wasn’t exactly the type of flower that you’d bring home to your significant other
-- it looks like a pair of little wisps with tiny leaves on the sides.
But to paleobotanists, Archaefructus is incredibly exciting,
because it’s among the earliest known examples of an angiosperm – what biologists call flowering plants.
If you see a piece of fruit on a tree or a flower in a garden, you’re looking at an angiosperm.
Also known as fruiting plants, angiosperms place their seeds inside an enclosure.
And that is, evolutionarily speaking, a big deal.
Because those enclosed seeds couldn’t just be pollinated by the wind, or the water.
Instead, for the first time, in order to reproduce, plants had to enlist the help of animals.
The main task of the flower, for example, is to attract pollinators,
so they can help with the dirty work of fertilization.
And the fruit that grows around the fertilized seeds is
basically just a tasty capsule that encourages animals to eat the seeds and then drop them elsewhere.
So basically, angiosperms evolved to hijack animals’ attraction to what’s fragrant and what’s tasty!
And you can see those beginnings in little Archaefructus, whose anatomy had a lot in common with modern flowers.
For example, Archaefructus had modified leaves that
surrounded its egg cells, forming what’s called a carpel.
And it had pollen-producing organs, called stamens.
These features are seen in flowering plants today
But instead of being wrapped up in pretty petals like the flowers we know,
these reproductive parts were arranged along the stem of the plant.
Nonetheless, Archaefructus and others like it marked a turning point in the evolutionary history of plants.
Once that started, neither plants nor animals would ever be the same.
Angiosperms spurred the evolution of many different pollinators,
some of which unknowingly became adapted to help plants reproduce.
And in time, flowering plants took over the world.
By the time of Triceratops and T. rex in the late Cretaceous,
angiosperms were becoming more plentiful
replacing the cycads and conifers that had grown there before.
Eventually, they took on more familiar forms,
as the world saw its first forests of magnolias, oaks, and beech trees.
Today, flowering plants make up the biggest single group in the Plant Kingdom,
accounting for more than 80 percent of the world’s terrestrial plants.
It may be strange to think of something as fragile as Archaefructus
as starting a global revolution, but that’s exactly what angiosperms did.
And to think it all started with a little wisp of a plant that sprouted in the shadows of the dinosaurs.
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