Lesson 4.1 quiz

The principle that states that geologic processes that are true today also were true in the past This concept is fundamental in understanding geological time and processes.

The process that breaks down rock and other substances through heat, cold, water, ice, and gas Weathering is a key factor in soil formation and landscape changes.

The process of removing rock by wind, water, ice, or gravity Erosion often works in conjunction with weathering to shape landscapes.

Mechanical Weathering: * Physically breaks rock into smaller pieces * Causes: freezing and thawing, release of pressure, plant growth, actions of animals, abrasion Chemical Weathering: * Breaks down rock through chemical changes * Causes: water, oxygen, carbon dioxide, living organisms, acid rain Examples include rust formation in chemical weathering and abrasion by wind in mechanical weathering.

• Type of rock • Climate Certain minerals dissolve easier, and higher precipitation and temperatures accelerate weathering.

The loose, weathered material on Earth’s surface on which plants grow Soil is essential for agriculture and ecosystems.

• Mixture of rock particles • Decayed organic material • Water • Air • Humus: Decayed organic material in soil Humus enriches soil and improves its structure.

Soil forms over long periods through: * Weathering of rock * Mixing with surface materials Living things contribute by: * Decomposing organic matter * Mixing soil * Adding nutrients Soil has layers called Horizons, including Topsoil (A), Subsoil (B), and Bedrock (C).