Fossils are the remains and traces of ancient life. The word itself derives from Latin and literally means “something dug up.” Human beings have collected fossils for thousands of years – sometimes for cultural use, other times to trade and sell, but always out of an innate curiosity. Today, scientists understand that fossils provide the best record of the history of life on Earth. Paleontology, the branch of biology that studies fossils, gives us direct information about evolution (how life changes over time) and extinctions. By studying the succession of fossils through rock layers, scientists are able to learn about the history of life on Earth. And because new fossils are always being found, this story is ever-widening in scope, with each new find potentially providing answers – or raising new questions. Importantly, fossils are everywhere, in every state, and in every country. This means that anyone can potentially contribute to paleontology. By inspiring generations old and young, fossils encourage people from all walks of life to contribute to science, and to help tell the story of our planet – a story that is 4.6 billion years in the making.
Starting back in the Cambrian, animals with a vertebral column (fish) eventually led to greater complexity, spanning from amphibians to eventually, dinosaurs, birds and mammals. The vertebrates in this section are organized in descending order of complexity
Animals without backbones first appeared before the Cambrian Period. The Cambrian saw an ‘explosion’ of diversity, from which only a few groups have survived to the present day. Invertebrates are far more varied and abundant throughout Earth history than the more ‘advanced’ vertebrates.
Since the arrival of the first land plants in the mid-Paleozoic, this group has diversified and flourished. Common deciduous trees developed at the end of the Mesozoic, and grasses, which permitted herbivorous mammals to thrive, appeared even later. Amber and copal, fossilized tree resins, are best known for the broad selection of life-forms which they trapped and preserved.
Geological processes control the environment on every scale. Recent findings show erosion and sedimentary deposits even on distant planets. Meteorites are earthly arrivals from outer space (possibly even our own solar system). Common minerals are the building blocks of all rocks on Earth, and the same are also found in meteorites and other planets.