Chapter 8 Changes to Earth s Surface

1. Chapter 8Changes to Earth’s Surface Vocabulary and Concept Review

2. Lesson 1: What are Some of Earth’s Landforms? {Vocabulary} Landforms – A natural feature on Earth’s surface (Mountains, Hills, Plateaus, Valleys, etc.) Mountain – An area that is higher than the land around it. Topography – The shape of landforms in an area

3. Lesson 1: What are Some of Earth’s Landforms? {Concepts} Mountains & Hills – Mountains are areas of land that are higher than the surrounding area. Hills are similar to mountains but are much smaller, (<1,600 feet tall). Mountains are formed by: Volcanoes When blocks of Earth’s surface are pushed upward.

4. Lesson 1: (Cont.) Valleys & Canyons– Valleys are areas with higher land around them, they are between mountains. The bottom of a valley is called the floor and the sides are called walls. A canyon is a valley with steep walls. Valleys are formed by: Moving water or ice cutting through rock and soil Because of erosion, most valleys have very fertile soil on their floors.

5. Lesson 1: (Cont.) Plains & Plateaus– Plains – large areas of flat land, plains can have rolling hills or a slight slope, but no highlands or deep valleys. A valley that slopes down toward the sea is called a coastal plain. Floodplains are plains that are flooded often by surrounding rivers. Plateau – a flat area that is higher than the land surrounding it (kind of like a table top). Mesas – are smaller than plateaus, but have the same shape Butte – Same shape, but smaller than a mesa

6. Lesson 1: (Cont.) Deltas & Dunes– Deltas form at the end of rivers. When rivers flow into lakes or oceans, the water slows down, when this happens, some of the sediment they are carrying is deposited, creating a delta. Dunes – are formed by sand that is carried by the wind. Dunes can be found in the desert, or along sandy coasts.

7. Lesson 1: (Cont.) Islands- An island is a body of land surrounded by water. Formed by: Parts of mainland that were partially covered by water, separating them by water. Some islands are the tops of underwater volcanoes. Barrier islands are formed by sand that is deposited near a shore by waves. Coral islands are formed from the remains of tiny sea animals. Their remains form large structures of limestone in the ocean.

8. Lesson 2: What Causes Changes Earth’s Landforms? {Vocabulary} Volcano – A mountain that forms as lava flows through a crack onto Earth’s surface. Earthquake – The shaking of Earth’s surface caused by movement of rock in the crust. Deposition – The dropping of bits of rock and soil by a river as it flows. Glacier – A large, moving block of ice

9. Lesson 2: What Causes Changes Earth’s Landforms? {Concepts} Layers of the Earth: Crust – the thin outer layer of the earth. Mantle – a thick layer of rock under the crust. Outer Core – near the center of the earth, the outer core is liquid. Inner Core – solid, but very hot, almost as hot as the sun!

10. Lesson 2: What Causes Changes Earth’s Landforms? {Concepts}

11. Plates The crust and upper mantle are made of large slabs of rock, called “Tectonic Plates” These plates move on a layer of the mantle that flows around like taffy. The plates move very, very slowly (you can’t see them move, they only move centimeters per year) This movement can cause landforms to be created. Lesson 2: (Cont.)

12. Volcanoes- A mountain that forms as lava flows through a crack onto Earth’s surface. Volcanoes cause very fast changes to Earth’s surface. Earthquakes- Are caused by movements of plates along “Faults”. A fault is a break in the crust, where the plates move. Earthquakes also cause fast changes to the surface of the Earth. Lesson 2: (Cont.)

13. Rivers – Flow and cause deposition (the dropping off of sediment). This deposition can cause new landforms to be created. Rivers cause slow changes to the surface of the Earth. Glaciers – Large, moving masses of ice As glaciers move, they can cause slow changes to the surface of the earth.

14. Lesson 2: (Cont.) Wind – Wind can cause erosion in sandy and dry areas. Wind can cause new landforms (dunes) and can help to weather other landforms. Wind causes slow changes to earth’s surface. Waves – Waves that crash into rocky cliffs can cause weathering over time. Waves can also wash sand from beaches and deposit it in new places. Waves also cause slow changes to the surface of Earth.

15. Lesson 3: What are Fossils? {Vocabulary} Fossil – The remains or traces of a plant or animal that lived long ago Fossil Record – The information about Earth’s history that is contained in fossils.

16. Lesson 3: What are Fossils? {Concepts} Most fossils form in sedimentary rock, and are “rock copies” of a bone, not actual bones. The soft parts of animals are not fossilized (eyes, tongues, heart, etc.) Hard parts of animals can fossilize (teeth, bones, shell, etc.)

17. Lesson 3: What are Fossils? {Concepts} Types of Fossils: Mold and Cast – rock copies of the hard parts of animals. Petrification – cells of plants or animals are replaced by rock (petrified wood) Trace fossils – are not body parts, but footprints, animal droppings, etc., that have been fossilized. Ice/Tree Sap fossils – animals/plants that were trapped in ice or tree sap and are preserved in either sap or ice.

18. Lesson 3: What are Fossils? {Concepts} Fossil Record – The information about the history of Earth that is contained in fossils. Because of the fossil record, we know about dinosaurs and other animals that lived and died long ago. The fossil record also shows how species and the environment have changed over time.

19. Lesson 3: What are Fossils? {Concepts} Geologic Time Scale – A table of 4 eras of Earth’s history. Cenozoic Era – Present time, humans first appeared in this era. Mesozoic Era – Dinosaurs were dominant during this era. Paleozoic Era – Trilobites were dominant during this era. Precambrian Time – One-celled organisms were dominant during this time.