Fossils and Geological Eras

A fossil mold is an impression left in sediment by an organism that later decays, leaving a negative space of the original shape.

In geology, an eon is the largest division of time, containing eras, periods, and epochs.

The Cenozoic Era is widely known as the Age of Mammals because mammals diversified and became the dominant land animals during this time. The Mesozoic is the Age of Reptiles, and the Paleozoic predates the rise of modern mammal dominance.

Carbon films occur when an organism is compressed under high pressure, driving off liquids and gases. This leaves behind a thin, dark film of carbon that preserves the outline of the organism.

Fossil fuels are non-renewable energy sources formed from the remains of ancient plants and animals over millions of years.

Amber is fossilized tree resin that often traps and preserves small organisms like insects in great detail. Other options like imprints or casts do not typically preserve the internal structures of insects.

Mammoths have been famously preserved in frozen ground (permafrost) in regions like Siberia, which keeps their tissues intact.

Embryology, DNA, and fossils are all direct evidence for evolutionary relationships and history. Radiometric dating is a tool used to date rocks and fossils, but it is not itself evidence of biological evolution.

The most recent glacial period, often referred to as the last ice age, ended approximately 11,700 to 11,800 years ago.

The Cretaceous-Paleogene extinction event, which wiped out the non-avian dinosaurs, resulted in the loss of approximately 70-75% of all species on Earth.

The current scientific consensus suggests a chain reaction: a massive meteor impact triggered widespread volcanic activity, which released enough dust and gas to block sunlight, causing a collapse of the food chain.

Non-avian dinosaurs went extinct approximately 65.5 to 66 million years ago at the end of the Cretaceous period.

The Mesozoic Era (252 to 66 million years ago) is famously known as the Age of Reptiles, during which dinosaurs were the dominant terrestrial vertebrates.

The Permian-Triassic extinction event, which ended the Paleozoic era, is widely attributed to massive volcanic eruptions (the Siberian Traps) that caused extreme climate change.