Living fossils such as the horseshoe crab have existed for millions of years.
A living fossil is a plant or animal that closely resembles its ancestors from the fossil record. Charles Darwin coined the term after discovering that living specimens of the gingko tree have leaves nearly identical to those found on fossilized gingkos dating to the Triassic Period 240 million years ago. Today, hundreds of living things have been discovered that seem unchanged since ancient times.
Animal Species
The coelacanth is one of the most famous living fossils ever discovered. These primitive fish give scientists insights into what life was like 450 million years ago when the earliest vertebrates appeared. One of the few mammalian living fossils, the egg-laying platypus was considered a hoax when it was first discovered. The horseshoe crab is a relative of ticks, spiders and scorpions that originally developed about 445 million years ago. The lungfish was discovered in the 1830s, about a century before the coelacanth. As its name implies, the lungfish has primitive lungs for absorbing oxygen from the air. Scientists consider them ancestors of the tetrapods or four-legged animals.
Plant Species
The Gingko biloba first appeared on Earth more than 200 million years ago when dinosaurs became the dominant land animals.The dawn redwood, or Metasequoia glyptostroboides, first appeared about 90 million years ago. Once considered extinct,it was discovered in China by Dr. Ralph Chaney in 1948. It resembles the California coast redwood but it is a deciduous tree that looses its leaves in the winter. Cycads were once so numerous that the Mesozoic era is sometimes referred to as the age of "Cycads and Dinosaurs." Today, the 150 species are threatened by habitat loss and plant collectors. Cycads resemble palms, but they grow wood in concentric growth rings while palms do not.
Creationist View
Creationists believe that life was created through God's direct action. Many also believe that, except for minor changes, species we see today are basically the same as they were at the time of creation. Creationists such as Dr. Carl Werner, Dr. Joachim Scheven and Harun Yahya claim living fossils support this belief. They argue that since living fossils are physically identical to their ancestors from the fossil record that they are essentially the same animal or plant. Dr.Werner further argues that many fossilized examples of modern species have been found in the same layers as dinosaur fossils, evidence, in his opinion, that evolution never occurred.
Evolutionist View
Biologist Mark Ridley points out that there are two main conjectures about living fossils. One suggests that creatures didn't evolve much because they live in isolated, stable habitats and never had to adapt to new habitats. The other suggests that they don't have enough genetic variation to evolve much. Evolutionists believe living fossils show that evolution happens at different rates and help scientists understand that molecular evolution, or changes in DNA and amino acids, occurs separately from evolution in physical appearance. Modern species have undergone millions of molecular changes since life began. Living fossils may resemble their ancestors but they have many molecular differences. According to Professor Jerry A. Coyne, species are classified as living fossils based on physical resemblance rather than genetic identity.
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