8th Grade Science Study Guide: Earth History, Fossils, and Natural Selection

A collection of vocabulary flashcards covering key concepts related to Earth history, fossils, and natural selection.

Law of Superposition

In undisturbed sedimentary rock layers, the oldest layers are at the bottom and the youngest layers are at the top.

Fossils

Remains or impressions of organisms preserved in sedimentary rock, indicating changes in life over time.

Extinction

The end of an organism or species, meaning it no longer exists.

Adaptation

A trait that improves an organism's chances for survival or reproduction.

Natural Selection

The process by which individuals with advantageous traits survive and reproduce more successfully.

Embryology

The study of early developmental stages of organisms, showing similarities that suggest common ancestry.

Trait

A characteristic or feature of an organism.

Selective Pressure

An environmental factor that affects an organism's survival and reproduction.

Variation

Differences within a population that can affect survival and reproduction.

Population

A group of the same species living in a shared environment.

Common Ancestry

The concept that different species share a common ancestor, evidenced by similarities in embryonic structures.

Environmental Change

Alterations in the environment that can shift the traits that are favored for survival.