Fossils
People have found fossils throughout human history and have pondered the existence of extinct animals. Fossils sparked stories about monsters and other weird creatures in antiquity. The discovery of “dragon bones,” which were most likely dinosaur remains found in China 2,000 years ago, is reported by the Chinese author Chang Qu. The mythological gryphon, which had an eagle’s head and wings and a lion’s body, was most likely inspired by Protoceratops skeletons that nomads in Central Asia found.
The Greeks were reminded of ram horns by another fossil. After the Ram god Ammon, the Greeks gave them the name Ammonites. Similar to this, fossilized elephant skulls discovered in Crete and other Mediterranean islands may be the source of Cyclops’ mythology. Do you understand why?
Numerous real-life organisms whose remains turned into fossils were equally amazing as the legendary beings they served as models for. Up to 12 meters (39 feet) was the maximum wingspan of the enormous pterosaur Quetzalcoatlus. An estimated 80,000 kg, or the weight of seven elephants, made up the dinosaur Argentinosaurus! Other fossils, like the ammonite and trilobite, astound us with their exquisite beauty and strange formations.
How Fossils Form
Any remnants or evidence of an extinct organism are called fossils. Body fossils, which remain after the soft parts have decomposed, and trace fossils, which include burrows, trails, or fossilized waste (feces), are examples of fossils.
Fossilization is the process by which a once-living organism turns into a fossil. Only a very small portion of all the species that have ever lived on Earth have ever undergone the process of fossilization, making it an extremely unusual occurrence. Consider the death of an antelope on an African plain to understand why.
Scavengers devour the majority of its body very fast, while bacteria and insects quickly consume the flesh that remains, leaving only a few scattered bones. The bones gradually become smaller and more dispersed over time, eventually becoming dust and replenishing the earth with their nutrients. Any of the antelope’s remnants would be extremely unlikely to have survived as a fossil.
When shellfish such as clams and oysters die, a similar process takes place on the ocean floor. The soft components break down fast, leaving the shells strewn all over the ocean floor. In shallow water, wave action quickly reduces the shells to fragments the size of sand. Worms, sponges, and other animals attack the shells even when they are not in shallow water.
Fossilization is very rarer for animals without hard shells or bones. As a result, there are few soft-bodied organisms in the fossil record, and there are a large number of animals with hard parts like shells and bones. The fossil record for slugs, worms, or jellyfish is essentially nonexistent. The most prevalent land animals, insects, are hardly ever encountered as fossils. Mammal teeth make up a significant amount of the fossil record for mammals since they are far more resilient than other bones.
This means that while many species with hard parts, such as shells or bones, will be represented in the fossil record, the many organisms with soft bodies that coexisted at the same time will nearly invariably be absent.
The primary cause of fossilization is prompt burial because the majority of degradation and fragmentation take place at the surface. Sediment transported by the river may bury marine species that perish close to a river delta. Skeletal remains may be covered and preserved by shifting silt on the ocean floor caused by a storm at sea.
Fossils of land plants and animals are, therefore, less abundant than those of marine organisms since burial rarely occurs on land. Terrain creatures may be buried by sandstorms, mudslides, volcanic ash, or falling rocks. Mud can also hide skeletons in bogs, lakes, and marshes. In Los Angeles, California’s La Brea Tar Pits are some of the best-preserved terrestrial animal skeletons. The creatures who were imprisoned in the trenches most likely died a slow and painful death, but the sticky tar preserved their bones admirably.
Thousands of scientists have found, studied, and recognized billions of fossils despite the challenges associated with preservation. The fossil record is not only a valuable source of information about previous climates and geological circumstances but also the finest guide to the history of life on Earth. Our existence has also been significantly impacted by the fossil record. The decomposing remains of plants and animals that once lived millions of years ago give rise to fossil fuels like coal, gas, and oil.
Clues from Fossils
Our best source of information on the evolution of life on Earth is fossil evidence. Furthermore, fossils can provide us with information about previous climates, plate movements, and other significant geological occurrences.
The first hint provided by fossils is the distinction between terrestrial (on land) and marine (underwater) environments. Fossils can reveal, in addition to the properties of the rock, the depth of the water and the speed at which sedimentation occurred. Scientists can determine the amount of wave action or storm frequency by analyzing the degree of wear and fragmentation on a fossil.
Fossils of aquatic life are frequently discovered atop or close to high mountains. For instance, trilobites, brachiopods, and other marine fossils can be found in the Himalayas, the world’s tallest mountains. This suggests that massive mountains were formed by the uplift of rocks on the seabed. About 40 million years ago, the Indian Subcontinent started to crash into Asia, causing the Himalayas.
Additionally, fossils can provide hints about historical climate. For instance, coal deposits and plant fossils have been discovered in Antarctica. Antarctica must have been a lot warmer in the past despite being cold today. This occurred as a result of both changes in Earth’s climate and the fact that Antarctica has not always been at the South Pole.
Numerous mass extinctions—periods when a large number of species went extinct—are among the most intriguing patterns seen in the fossil record. The greatest mass extinction in Earth’s history happened around the end of the Permian period, roughly 250 million years ago, despite the fact that the one that wiped off the dinosaurs is the most well-known. It’s estimated that approximately 95% of Earth’s species became extinct as a result of this disaster! Although the exact cause of these mass extinctions is unknown, the majority of scientists think that at least some of these tragedies were caused by collisions with comets or asteroids.
In the End
Fossils provide invaluable insights into Earth’s history, offering glimpses into past life forms and ecosystems. Their study aids in understanding evolution, paleoclimate, and geological processes. As windows to the past, fossils illuminate the interconnectedness of life and underscore the importance of preserving our planet’s rich natural heritage.