Introducing KNOVA — A free reading app with curriculum-aligned passages on History & Science for Grades 3-8Learn More →

Biological Weathering: Types and Examples — Reading Comprehension

No ratings yet|

Grades

Standards

MS-ESS2-1
MS-PS1-2
RST.6-8.3

Rate this resource

Send Feedback / Report an Issue

About This Reader

This passage details biological weathering processes, connecting to NGSS MS-ESS2-1 (Earth's systems) and LS2.B (ecosystem interactions). It covers root penetration, lichen acid secretion (chem standards MS-PS1-2), and human impacts. Examples range from Yosemite's lichen-covered boulders to Angkor Wat's root damage. The text supports CCSS.ELA-LITERACY.RST.6-8.3 for sequencing scientific processes and emphasizes real-world applications in archaeology and soil science.

CONTENT PREVIEW

angkor wat, root, nature, cambodia, wat, grown together, jungle, temple, tree, southeast, asia, so, old, mystical, tomb raider, rubber tree — "Tree Growing Over Temple Ruins, Angor Wat, Cambodia" by Simon / Pixabay.

Biological weathering occurs when living organisms break down rocks through physical or chemical processes. Unlike mechanical or chemical weathering alone, this type involves direct biological activity, contributing to soil formation and landscape evolution.

Types of Biological Weathering

Physical (Mechanical) Breakdown

○ Plant Roots: Growing roots penetrate cracks, prying rocks apart (e.g., tree roots splitting sidewalks).

○ Burrowing Animals: Creatures like earthworms and rodents expose rocks to further weathering by displacing soil.

Chemical Breakdown

○ Lichens & Mosses: Release acids (e.g., oxalic acid. that dissolve minerals in rocks.

○ Bacteria/Fungi: Produce organic acids or chelating agents that weaken rock structures.

Human Activities

○ Mining, construction, or even hiking trails accelerate rock breakdown.

Examples

● Lichen-Covered Boulders (Yosemite National Park): Lichens slowly dissolve granite surfaces.

● Tree Roots in Ancient Ruins (Angkor Wat, Cambodia.: Roots disrupt stone temples over centuries.

● Mussel Boring (Coastal Rocks): Marine organisms chemically erode shorelines.

Biological weathering plays a key role in nutrient cycling, enabling ecosystems to thrive. However, it can also threaten archaeological preservation. Understanding these processes helps in conservation and soil management efforts.

Fun Fact: Tree roots can exert pressures of up to 725 pounds per square inch when growing through rock cracks—enough force to lift sidewalks and split boulders! Some lichens that grow on rocks produce acids strong enough to dissolve granite, which is why even the hardest stone monuments eventually show signs of biological weathering.

What defines biological weathering?

Wind erosion onlyRock breakdown by living organismsVolcanic rock formationGlacier movement

How do lichens weather rocks?

By freezing water in cracksReleasing acids that dissolve mineralsCausing earthquakesReflecting sunlight

Which is NOT a biological weathering agent?

Tree rootsEarthwormsGlacier iceMoss

Why is Angkor Wat an example?

Tree roots physically disrupt stoneIt’s made of unweatherable metalLocated in a desertBuilt by weathering-resistant lichens

How does human activity contribute?

By planting lichensThrough mining/constructionBy stopping all erosionCreating artificial glaciers

What role does biological weathering play?

Prevents soil formationSpeeds up nutrient cyclingStops rock breakdownOnly harms ecosystems