"The Weight of a Petal Has Changed the Face of the World" (Coevolution of Plants & Animals)

People—most of them—like flowers. 

Most of us don’t know it, but it is very likely that we owe our existence to them.

Things changed in a big way when flowers, along with the multitudinous variety of fruits they produce, first made their appearance onstage something like ?? million years ago.

Up to that time the only plants around were the so-called gymnosperms (a group including the conifers, cycads, ephedra, and a few others) and the more primitive sporophytes (plants that reproduce by spores rather than seeds, like ferns, horsetails, club-mosses?, and non-vascular sporophytes like mosses, liverworts, algae, fungi, lichens etc.)

These primitive plants were the marsupials of the vegetable kingdom, and like the marsupials, when a more “advanced” design came along—the placental mammals on the one case and the angiosperms (flowering plants) in the other—the older design was gradually replaced by the new.  In neither case, fortunately, has this process run its full course, and maybe it never will—we still have kangaroos and redwoods—but the balance did shift, and quite dramatically.  In the late Miocene, for example, there were at least two or three times as many species of pine as there are today.

But, back to the angiosperms.  When plants figured out how to make flowers and fruits, there came a huge burst of speciation/adaptive radiation.  A multitude of new species, genera, families, even orders of plants rapidly appeared, and with them an equal or even greater multitude of animals to take advantage of the feast, especially insects.  In fact, the boom worked two ways: animal and plant worked to mutually reinforce the multiplication of the other.  The more kinds of flowers and fruits, the more kinds of animals, and vice versa.  Insects acted as go-betweens to pollinate the flowers, and bigger animals carried the seeds far and wide, each kind unconsciously driving the evolution of the plants by selecting the richest nectar, the brightest and tastiest and most nutritious fruits and seeds of just the right size and type to suit itself.

[Add something about the other side of the coin, how plants “use” animals to do their bidding.]

Hummingbirds coevolved with hundreds of kinds of plants with tubular, brightly colored, nectar-rich flowers, etc. etc. . . .  And we primates coevolved with plants that produce sweet, tasty fruits.

Tough, bitter conifer needles might have been adequate for undiscriminating dinosaurs, but we humans are more particular.  Without the angiosperm revolution we would be living on pine nuts and “Mormon tea” and not much else.  More likely we wouldn’t be here at all.

Every one of our major food plants, not to mention fiber (cotton, etc.), medicines, beverages, “herbs” and spices, not to mention ornamental plants, are angiosperms.  This includes even our major staples the cereal grains (rice, wheat, corn, etc.); grasses too are “flowering” plants no less than are lilies.