Living fossils
Ever since life began on earth, a parade of different creatures has inhabited our planet. Some of them adapted and changed into new forms - a small, feathered dinosaur was the ancestor of birds, for example. Others died out. But occasionally we find a plant or animal that has survived almost unchanged for many millions of years. Here are a few:
The coelacanth
Until the early 1900s, coelacanths (SEE-luh-kanths) were only known from fossils. Scientists thought these fish had died out 75 million years ago.
But one hot summer day in 1938 in New London, South Africa, Marjorie Courtenay-Latimer made a surprising discovery. She was the director of a small museum. A local fisherman had called her to come see what he had caught. In the pile of fish, Miss Courtenay-Latimer saw a five-foot-long blue one with white spots. She'd never seen anything like it before.
She wrote a letter to the nearest fish specialist describing her find. It was during the Christmas holidays, and the mail was very slow. She waited a long time for a reply. In the meantime, she had a taxidermist mount the fish's skin. She asked the taxidermist to save the fish's insides, but they got so stinky they had to be thrown out.
The specialist, J.L.B. Smith, finally arrived. He examined the fish and declared that it was indeed a coelacanth. He named it Latimeria, in honor of Miss Latimer.
Dr. Smith was very upset that he had not been able to study the fish's inner organs. He spent years searching for a second specimen. He finally found one in 1952 - 14 years later - and was able to study it. Since then, many more of these prehistoric fish have been found and even filmed in the very deep waters in which they live.
The ginkgo
The ginkgo tree has no close relatives among living plants. Fossil imprints of ginkgoes date back more than 200 million years.
Ginkgoes were most abundant during the time of the dinosaurs. They became very scarce as dinosaurs died out. Scientists think maybe the trees needed king-size plant eaters to disperse their large seeds.
A small number of ginkgoes continued to grow in China. Then they gradually died out in the wild. But
Chinese Buddhist monks thought ginkgoes were very special and grew them in temple gardens and monasteries. This saved ginkgoes from extinction.
In the early 1700s, a German doctor named Engelbert Kaempfer brought back some ginkgo nuts from Japan. He planted one in the Dutch city of Utrecht, and it is still alive today. But even though it is almost 300 years old, it is a baby compared with those growing in Chinese temple gardens. Some of them are more than 3,000 years old!
Ginkgo trees are either male or female. Most of the ones you see in parks and on city streets are male, because the ripe fruit of the female tree smells awful. The nut inside is edible, though, and once the skin is removed it does not smell. In Japan, ginkgo nuts are eaten boiled or grilled.
The horseshoe crab
If you live on the East Coast, you have a living fossil right in your backyard. The horseshoe crab is actually not a crab at all. It is a distant relative of spiders and ticks. Horseshoe crabs spend most of their time on sandy or muddy ocean bottoms, where they grub for worms and other small creatures to eat.
In late spring, they come onto beaches to lay their eggs. Many shorebirds that winter in South America stop in Maryland, Delaware, and New Jersey on their way north. There, they stuff themselves on horseshoe-crab eggs before flying on to their summer nesting grounds.
In recent years, there have been fewer horseshoe crabs and fewer birds feeding on their eggs. Loss of crab habitat is one reason. Another is the fact that many crabs are caught and used as bait. Some are also taken for their bright-blue blood, which contains valuable chemicals. But these crabs are returned alive to the ocean, presumably unharmed.
Government and private groups are working to protect this ancient species. Clearly, horseshoe crabs are still a vital part of our ecosystem.
(c) Copyright 2000. The Christian Science Publishing Society
