Ch 14 The History of Life Vocabulary Cards

Isotope • Atoms of the same element with a different number of neutrons

Stratigraphy • Method used to determine the age of rocks by comparing them with other layers (above & below them)

Law of Superposition • Layers of rock closer to the Earth’s surface are younger and layers further from the Earth’s surface are older

Half Life • The amount of time it takes for ½ of the atoms in a substance to decay into another element.

Radiometric Dating • Using the decay of radioactive isotopes to measure the age of a rock.

Fossil • Any preserved evidence of an organism

Ch 15 Evolution Vocabulary Cards

Artificial selection • Humans breeding organisms to obtain specific traits

Natural Selection • Some organisms are better suited to their environment than others & are more likely to survive & pass on their traits

Variation • Small differences between members of the same species

Adaptation • Any trait that increases an organisms chance of survival and reproductive success.

Population • A group of organisms (same species) living and interacting with each other in an area

Heritability (inherit) • Passing on traits from parent to offspring

Fitness (Fit) • How well an organism is adapted to its environment in relation to other organisms.

Selective pressure • Any factor that makes it difficult for an organism to survive and reproduce.