] Here’s a riddle: Roses are red, violets are blue, flowers need bees, but bees need flowers too. These two branches on the tree of life have evolved to rely on each other so tightly, you can’t have one without the other. So which came first, bees or flowers? [MUSIC] Imagine a world without flowers. It’s hard to do, but 140 million years ago, this landscape would have looked completely different. [MUSIC] We’d see pterosaurs flying through the sky tiny rat-like mammals on the ground, and of course, dinosaurs. Plants first colonized land about 450 million years ago, but for their first 300 million years there wasn’t a single flower to be found.
Plants were limited to things like ferns, conifers, ginkgos, cycads. At the same time, there were plenty of insects that we’d recognize today, but no bees. Then suddenly, in the early Cretaceous, something amazing happened. It was like BAM, flowers everywhere. [MUSIC] Charles Darwin called flowers’ sudden arrival in the fossil record “an abominable mystery”. Today, there’s somewhere between 300 and 500 thousand species of angiosperms, making up 9 out of every 10 plants on Earth. Once flowers arrived on the scene, their branch on the tree of life really blossomed. [DRUM] Get it? Blossomed? Why were flowers such a big deal? Well, plants have a pretty tough love life. That one? Very pretty. Why don’t you just go over and talk to it? Oh, right you can’t, you’re attached to the ground. Be cool, it’s looking.
Despite being rooted to the ground, different types of plants have evolved different strategies for exchanging sex cells with far off partners. Non-flowering plants like conifers rely mostly on the wind to deliver their pollen, but that’s pretty inefficient, kind of like writing a love letter to your sweetheart, putting it in a bottle, and casting it out to sea. Probably not gonna work, Romeo. Apologies if this info ruins your next anniversary, but flowers are actually reproductive organs. And in order to increase the chance of fertilizing another plant, angiosperms have recruited their own special delivery service. Insects. Lots of people think nectar is the main that reason insects visit plants, but that’s not how it started 150 million years ago.
It’s this stuff. This is a Magnolia tree, one of the oldest flowering plant species still around today. Their flowers don’t produce any nectar. Instead, insects like beetles are after its pollen. Pollen is more than just the plant’s genetic material, it’s super-nutritious. The earliest pollinators came to eat this stuff, and they just so happened to drop a few crumbs along the way. This relationship, which we call mutualism, worked really well. Flowering plants pollinated by insects had an advantage over their wind-dependent cousins, and exploded and diversified. Insects now had a delicious reason to visit flowers, and flowers had a good reason to attract their hungry little cupids. This started an evolutionary advertising war. First white flowers, then bright-colored flowers, weird shaped flowers, intoxicating perfumes, all of them were like big neon signs.
To get a stem up on the competition, some flowers started to sweeten the deal with a sip of sugary nectar. And that’s where these ladies come onto the scene, nature’s finest flower farmers. Honeybees, with their elaborate hive societies and, well… honey, are by far the most famous, but many modern species of bees live alone, and that gives us a hint to their origin. By studying things like DNA and anatomy, we know that bees evolved from solitary, carnivorous wasps. These wasps would stock their nests with insect corpses, and if that insect had recently visited a flower, its corpse might be dusted with a little bit of pollen. Over time, some wasps replaced their dead insect diet with more and more protein-rich pollen. Bees are essentially wasps turned vegetarian! So plants were making flowers, and insects were pollinating them long before bees ever took to the air, but it was these special insects with their special adaptations that let flowering plants completely dominate the world like they do today. When it comes to pollinating, nothing does it better than a bee.
They have unique UV vision to home in on flower patterns we can’t see with our eyes, bristly hairs to collect huge baskets of pollen, and special long tongues to slurp up nectar. After the meteor impact that killed most of the dinosaurs, It was bees that allowed flowering plants to recover, and the fruits that those plants produced let mammals, big and small, fill the roles once occupied by dinosaurs. So while we rely on bees for a lot today, they pollinate about a third of the crops we eat, without them, we might never have evolved in the first place. So next time you stop and smell the flowers, thank the bees that got there first. Stay curious. Let’s say a special thanks to the LadyBird Johnson Wildflower Center for letting us come out and hang out with all of their flowers Go support wildlife conservation in your backyard. Because it’s the only backyard you have.