Unit 3 Vocabulary

Vertebrate

• An animal with a backbone.

• A type of fish without fins.

• An animal that lays eggs in water.

• A mammal that can fly.

Trace fossil

• A type of fossil that provides evidence of the activities of ancient organisms

• A fossil that is formed from the remains of an organism

• A type of fossil that shows the physical appearance of an organism

• A fossil that is created through volcanic activity

Half-life

• Length of time required for half of the radioactive atoms in a sample to decay

• The time it takes for a substance to double in quantity

• The period during which a substance remains stable

• The time required for a chemical reaction to complete

Law of Lateral Continuity

• Layers originally extended in all directions until it thinned out to zero or ended against the edges of another structure or deposit

• Layers are deposited in horizontal sheets that can be disturbed by tectonic forces

• Layers are formed only in water and cannot be found in terrestrial environments

• Layers are always thicker at the center and thinner at the edges

Plate tectonics

• A theory stating that the earth's surface is broken into plates that move.

• A concept that explains the formation of mountains through erosion.

• A hypothesis that suggests the earth's core is made of liquid metal.

• A model that describes the earth's atmosphere and its layers.

Capture Theory

• The idea that the moon was created at a different location in the solar system and subsequently captured by Earth's gravity

• The theory that the moon was formed from debris after a collision with Earth

• The hypothesis that the moon is a planet that was ejected from another solar system

• The belief that the moon was always part of Earth's formation process

Permian-Triassic extinction

• About 250 million years ago, around 95% of all marine species went extinct due to a comet impact.

• The extinction event was caused by a volcanic eruption that released large amounts of carbon dioxide.

• It occurred during the Jurassic period and affected mostly terrestrial species.

• The event was primarily due to a large release of methane gas from the ocean bottom.

Absolute dating

• A technique used to determine the actual age of a fossil

• A method for estimating the relative age of rocks

• A process for dating historical events based on written records

• A technique for measuring the temperature of fossils

Eon

• The smallest division of geologic time

• A significant stretch of time that includes multiple eras

• The largest division of geologic time, comprising two or more eras

• A period of time characterized by the dominance of a specific type of life

Relative dating

• Method of determining the age of a fossil by comparing its placement with that of fossils in other layers of rock

• A technique used to date rocks and fossils based on the decay of radioactive isotopes

• A process of determining the exact age of a fossil using carbon dating

• A method of classifying fossils based on their physical characteristics