12.1 The Fossil Record

These flashcards cover key concepts related to the fossil record and radiometric dating as outlined in the lecture notes.

What are the main types of fossil formation?

Fossils can form through permineralization, natural casts, trace fossils, amber-preserved fossils, and preserved remains.

What is permineralization?

Permineralization occurs when minerals carried by water are deposited around or replace a hard structure.

How does radiometric dating work?

Radiometric dating uses the natural decay rate of unstable isotopes to calculate the age of fossils.

What is a half-life in the context of isotopes?

A half-life is the amount of time it takes for half of an isotope in a sample to decay into a different element.

What is the significance of the isotope carbon-14 in dating fossils?

Carbon-14 is used for radiometric dating of recent remains, as it decays at a known rate and is absorbed by living organisms.

Why are meteorites important for determining the age of the Earth?

Meteorites provide unspoiled samples for radiometric dating, as they have not undergone recycling or erosion like Earth's rocks.

What is relative dating?

Relative dating estimates the age of fossils by comparing their placement in rock layers.

What role do isotopes play in radiometric dating?

Isotopes, which have the same number of protons but different neutrons, decay at a constant rate, allowing for age estimation.

What conditions are ideal for fossilization?

Fine sediment, rapid burial, and environments such as wetlands and river mouths promote fossilization.

What is a trace fossil?

A trace fossil records the activity of organisms, including nests, burrows, imprints, and footprints.

What happens to carbon-14 after an organism dies?

After death, the intake of carbon stops, and the decay of carbon-14 continues, which allows scientists to estimate the age of the fossil.