Biology Chapter 14: Fossil Formation

Study Notes

Fossils

A fossil is any preserved evidence of an organism.
Organisms that are buried rapidly in sediment are preserved and can become fossils.
Fossil formation occurs when organisms die, are buried by sediment, and minerals replace the spaces created by bones and hard parts of the organism.
Erosion can expose fossils.

Paleontologists

Paleontologists are scientists who study fossils.
They read and record fossils to learn about the diet and environment of ancient organisms.

Dating Fossils

Relative dating finds the age of a rock by comparing rock layers.
The Law of Superposition states that younger layers are on top of older layers.
Radiometric dating measures the decay of radioactive isotopes to determine the age of rocks.
Half-life is the time it takes for the amount of a radioactive isotope to decay.
Geologists use the half-life of isotopes to determine the age of rocks.

Geological Time Scale

The geological time scale shows major geological and biological events in Earth's history.
The Precambrian era spans the first 4 billion years of Earth's history.
The Phanerozoic eon is divided into the Paleozoic, Mesozoic, and Cenozoic eras.
The Paleozoic era saw the Cambrian explosion, mass extinctions, and the emergence of life on land.
The Mesozoic era was marked by the evolution of dinosaurs, birds, and mammals.
The Cenozoic era saw the evolution of mammals as dominant land animals and the emergence of humans.

Early Ideas about Life

Spontaneous generation was an early idea that life could arise from non-life.
The theory of biogenesis states that living organisms produce new living organisms.
Louis Pasteur's experiment showed that microorganisms cannot arise spontaneously.

Modern Ideas about Life

Biologists believe that life arose from a series of chemical events on Earth.
The primordial soup hypothesis suggests that organic molecules could have formed in the early Earth environment.
The Miller and Urey experiment showed that inorganic compounds can produce simple organic molecules.
Later experiments showed that precursors to nucleotide bases can form with simpler molecules in early Earth environments.

Levels of Organization within the Biosphere

The biosphere is the part of the Earth where life exists.
Biomes are groups of ecosystems with a similar climate.
A community is a group of populations that interact in an area.
A population is a group of the same species that interbreed and produce offspring.
A species is a group of similar organisms that can interbreed and produce offspring.

Interactions with the Environment

Ecology is the study of the interactions among organisms and their environment.
An ecosystem is the area where these interactions take place.
Biotic factors are living, while abiotic factors are non-living.
Aquatic and terrestrial ecosystems support different forms of life.
Biodiversity is the variety of organisms in an ecosystem.
An organism is a single living thing within an ecosystem.
A habitat is a place where an organism obtains the necessary resources.
A niche is the unique job of an organism in an ecosystem.

Description

Explore the process of fossil formation, from decomposition to sediment burial, and learn about the role of erosion in exposing fossils. Discover how organisms are preserved and turned into fossils, and what paleontologists can learn from them.