None of our garden flowers is ancient. Neither are the trees of the woods. They evolved only within the past few million years. All kinds of plant life that have flowers and seeds are quite new. Only in the simpler forms do we find the old ones.

Since evolution works from the simple to the more complicated, we know that the seaweeds evolved before the ferns, and the ferns before the pines, and the pines before the oaks.

Plant life, like animal life, began in the sea. A billion years ago or more, simple one-celled plants developed. Some were of the microscopic kind we call bacteria. Others belonged to the almost equally simple group known as blue-green algae.

Bacteria do not usually leave fossil remains. Blue-green algae sometimes do, surviving as shiny black films on ancient rocks. The study of such films on rocks led botanists to think that the blue-green algae have not changed very much through the ages. They are our oldest plant living fossils.

During the Devonian period, about 350 million years ago, both plants and animals began to leave the sea for the land. The first to arrive on land were the flat, scaly ones known as lichens. These tough plants still exist, and can be seen as grayish or greenish coating on rocks in many parts of the world.

The next to appear were the psilophytes. They have long been extinct, but they were the ancestors of all the land plants of today. Though the psilophytes are gone, they have left two near relatives as living fossils. Both are found only in tropical countries. They are Tmesipteris, from the Philippines and New Zealand, and Psilotum, which lives in the Americas from Florida southward.

A living fossil often used as a Christmas decoration is ground cedar, which looks like a miniature evergreen tree. Another Christmas favorite is ground pine, with sharp needlelike leaves. A third is running pipe, whose stems run along the ground for ten feet or more. None of these little plants belongs to the family of evergreen trees. They come from a group of plants that was ancient long before the first pine tree sprouted – the club mosses.

Living fossils that everyone knows are the ferns, those attractive leafy plants found in the cool forests of the north and the steaming jungles of the tropics. Ferns stand midway in the evolutionary scale of plants. They reproduce by spores, not by flowers and seeds, and that is what sets them apart from the highest group of plants.

None of the modern tree ferns is exactly like their Carboniferous ancestors, but the relationship is close enough so they can be called living fossils. Tree ferns live only where the weather is hot and the rainfall is heavy. They are most common in Australia, New Zealand, and South America.

The bird was about the size of a hen. It had no sign of wings or a tail. It seemed to be covered with a shaggy coat of hair, rather than feathers. Its four-toed feet were huge, and so was its beak, which had nostrils placed right at the tip. It looked more like a hobgoblin than a bird.

One of the scientists gave it a Latin name: Apteryx australis, which meant “southern bird without wings.” Another thought it might be related to the penguins. A third man suggested it was a dwarf ostrich.

In time the truth became clear. The hairy, long-billed bird belonged to a special group called Ratites, which had stopped flying 100 million years ago, or possibly never did fly at all. This wingless furry bird, which the Maoris called the kiwi, was in fact linked to the emu and the cassowary.

All these birds have special features setting them apart from other birds. Their feathers are stringy, looking more like fur or hair. They lay huge eggs and their legs are very strong. The kick of an ostrich, for instance, can kill a man.

The kiwi is the only living bird that has a sense of smell and it can be heard making loud sniffing noises as it pokes its bill along the ground. It has sharp powerful claws, which it uses to defend itself.

It is a comical-looking creature to begin with. What makes it more amusing is its occasional habit of sleeping in a “three-legged” position, resting the tip of its bill on the ground.

Perhaps the most unbelievable thing about the kiwi is the size of its eggs. Though not bigger than a hen, a kiwi lays eggs as big as an ostrich’s. Kiwi eggs as large as 5 by 2¾ inches have been laid, weighing a third as much as the bird that laid them!

These flightless birds are living fossils that tell us a great deal about evolution. We do not know for sure whether they have been changed by time. Very little fossil information is available about them. Even the extinct forms died out only a few centuries ago.

How can we call them living fossils, then, if we do not have the fossils of their ancestors?

Scientists think they are because they look much more primitive than the flying birds. They appear to go back to the time when the first birds were evolving.

That was in the Jurassic period, when dinosaurs walked the earth. The oldest known fossil bird is called Archaeopteryx, a name that means “ancient bird.” Perhaps some Jurassic or Cretaceous family of small dinosaurs evolved into the ancestors of the kiwi and the ostrich. Many dinosaurs walked on their hind legs and were only a few feet tall.

The oldest ostrich fossils discovered so far are only about a million years old. So it is only a guess that the flightless two-legged birds are members of an ancient line of evolution, separate from the main stock of flying birds.

The tuatara looked like a lizard with an oversized head. Its tail is short and thick, its eyes are huge, and a crest of spines ran down its neck, back, and tail. Rough, sand-feeling scales cover it, and its rumpled, wrinkled skin seems to be too large for the animal inside.

A zoologist named John Edward Gray examined it and gave it the scientific name of Sphenodon punctatus (“pointed wedge-toothed reptile”). Looking closely, Gray saw a ring of scales on the crown of the head surrounding a single transparent scale – a kind of peephole. Underneath the transparent scale, Gray discovered an organ that looked very much like an eye.

Not a lizard, though it looks like one, the tuatara is the last of the rhynchocephalians, the beak-headed, three-eyed reptiles. They lived before the dinosaurs.

Unlike all other living reptiles, it has teeth that grow right out of its jawbone, with thick, unusual ribs, and vertebrae with hollow sides. It also has that third eye.

The extra eye does not really see. It is smaller than the other two, and is covered by the transparent scale that almost entirely hides it. However, there is a nerve leading from the eye to the tuatara’s brain. Probably the eye can register changes in light and dark, if nothing more. In the millions of years since the other rhynchocephalians died out, the tuatara’s third eye has lost most of its function, though not all.

In almost all living reptiles, it is possible to detect the place where the third eye used to be. There is often a tiny opening in the skull, and a small round growth that is the evolutionary descendant of the extra eye, hidden beneath the skin.

Tuatara-like reptiles once were found in many parts of the world. A fossil rhynchocephalian called Homeosaurus has been unearthed in England and Bavaria. It lived 145 million years ago, and from its skeleton, it seems to have looked almost exactly like the tuatara.

The three-eyed ones spread down through Asia into Malaya. In the Jurassic period, land bridges connected many of the islands of the Pacific. Crossing on the bridges, the tuatara reached the islands of New Zealand. Some time later, the land bridges sank. New Zealand was separated from the rest of the world, and the tuatara remained undisturbed in its remote island home.

Today New Zealand is the only place in the world where it can be found, and it is rare even there. It is against the law in New Zealand to kill a tuatara or even to keep one as a pet. A government permit is needed to simply visit one of the islands where they live.