Geography · 7th Grade · Regional Study: The Americas · Weeks 19-27

Physical Geography of South America

Exploring the major landforms, climate zones, and natural resources of South America, including the Andes and Amazon.

• Common Core State Standards
• C3: D2.Geo.4.6-8
• C3: D2.Geo.7.6-8

About This Topic

South America contains some of the most dramatic physical geography on Earth. The Andes Mountains, running the full length of the continent's western edge, form the longest continental mountain range in the world and divide the continent into sharply contrasting climate zones. The windward and leeward effects of the Andes create the extreme conditions ranging from the hyper-arid Atacama Desert on the western slopes to the humid tropical forests of the interior. For US 7th graders, this topic builds the physical geography foundation for understanding everything else about the region.

The Amazon Basin spans roughly 40% of South America and contains the world's largest tropical rainforest by area. Its combination of high rainfall, warm temperatures, and nutrient-poor soils creates conditions supporting extraordinary biodiversity while challenging conventional agriculture. The Pampas grasslands of Argentina and Uruguay show how vast flat plains with fertile soils become a continent's agricultural heartland. These contrasts help students understand physical geography not as a backdrop but as an active force shaping what is economically and ecologically possible in each region.

Active learning fits this topic well because South America's physical geography tells clear visual stories. Students who work with elevation profiles, climate charts, and satellite imagery to identify why each region looks and functions as it does build the spatial reasoning skills central to geographic thinking.

Key Questions

1. Explain how the Andes Mountains create diverse climate zones in South America.
2. Analyze the unique biodiversity of the Amazon Basin and its global importance.
3. Compare the physical geography of the Atacama Desert with the Pampas grasslands.

Learning Objectives

• Compare the physical characteristics of the Andes Mountains and the Amazon Basin, identifying at least three distinct landforms in each.
• Explain how elevation and proximity to the equator influence temperature and precipitation patterns in South America, citing specific examples.
• Analyze the relationship between specific landforms (e.g., Andes, Amazon River) and the distribution of unique plant and animal species.
• Evaluate the role of natural resources found in South America, such as fertile soil in the Pampas or mineral deposits in the Andes, in regional economic activities.

Before You Start

Introduction to Continents and Oceans

Why: Students need a basic understanding of global geography and the location of continents before studying a specific region like South America.

Basic Map Skills: Latitude, Longitude, and Scale

Why: Understanding latitude and longitude is essential for comprehending climate zones and the location of major geographical features.

Elements of Weather and Climate

Why: Prior knowledge of concepts like temperature, precipitation, and wind is necessary to analyze the climate zones of South America.

Key Vocabulary

Andes Mountains	A major mountain range running along the western coast of South America, influencing climate and creating diverse ecosystems.
Amazon Basin	A vast, low-lying region in South America dominated by the Amazon River and its rainforest, known for its exceptional biodiversity.
Atacama Desert	A hyper-arid desert plateau on the western edge of South America, known for its extreme dryness and unique adaptations of life.
Pampas	Expansive, fertile grasslands in southeastern South America, primarily in Argentina and Uruguay, crucial for agriculture.
Rain Shadow Effect	A phenomenon where one side of a mountain range receives much less precipitation than the other side due to air masses being forced upward and releasing moisture.

Watch Out for These Misconceptions

Common Misconception

The Amazon is a single uniform habitat.

What to Teach Instead

The Amazon Basin contains many distinct ecosystems, including flooded forests, white-sand forests, cloud forest margins, and savanna-forest transitions. Climate, soil chemistry, and flooding patterns create these distinctions. Satellite image comparisons showing the Amazon in different seasons and from different latitudes quickly correct the single-habitat image.

Common Misconception

The Andes only creates cold climates.

What to Teach Instead

While Andean peaks are cold, the mountain system also creates warm sheltered valleys (like Cuzco's valley), fog-desert conditions on western slopes, and high-altitude wetlands on the altiplano. The relationship between altitude, wind direction, and moisture determines climate, not altitude alone. A transect analysis that shows temperature and rainfall data at multiple points on the same mountain makes this relationship clear.

Common Misconception

The Atacama Desert is the world's largest desert.

What to Teach Instead

The Atacama is the world's driest non-polar desert by precipitation but is not the largest by area. Antarctica and the Sahara are both larger. The distinction matters for understanding what desert means: a region with very low precipitation, not necessarily a hot, sandy landscape of any particular size.

Active Learning Ideas

Cross-Section Analysis: The Andes Climate Transect

Give each pair an elevation profile running west-to-east across South America at approximately 15 degrees south latitude, plus temperature and rainfall data for 6-8 stations along the transect. Students annotate the profile with climate zones, identify orographic effects on each slope, and sketch what vegetation they would expect at each station. Groups compare annotations and resolve disagreements by returning to the data.

35 min·Pairs

Gallery Walk: South American Biomes

Post large photographs of 6 biomes (Atacama, Patagonian steppe, Pampas, Amazon rainforest, Cerrado, high Andes puna) with data cards showing altitude, annual rainfall, and temperature range. Students rotate and write one geographic factor at each station that explains why that biome exists in its location. The class then assembles a cause-and-effect map showing how the Andes and Atlantic moisture together explain the continent's biome pattern.

30 min·Small Groups

Jigsaw: Amazon Biodiversity Layers

Expert groups each study one aspect of Amazon biodiversity: canopy layer species, river and fish diversity, insect and invertebrate species, and endemic mammals. Groups reform into mixed groups and teach each other, using a blank vertical cross-section of the forest that they label together to show how physical geography creates the conditions for each layer's distinct species communities.

40 min·Small Groups

Real-World Connections

• Geologists and mining engineers work in the Andes Mountains to extract valuable minerals like copper and gold, which are then processed and exported globally.
• Biologists and conservationists study the Amazon rainforest to document its incredible biodiversity and develop strategies to protect endangered species and ecosystems from deforestation.
• Agricultural scientists and ranchers utilize the fertile soils of the Pampas to raise cattle and grow crops like soybeans and wheat, contributing significantly to global food supplies.

Assessment Ideas

Exit Ticket

Provide students with a blank map of South America. Ask them to label the Andes Mountains, Amazon Basin, Atacama Desert, and Pampas. Then, have them draw arrows indicating prevailing winds and briefly explain the rain shadow effect on one side of the Andes.

Quick Check

Present students with three short descriptions of different South American environments. For each description, students must identify the corresponding physical region (e.g., Andes, Amazon, Atacama, Pampas) and state one key characteristic that helped them decide.

Discussion Prompt

Pose the question: 'How does the physical geography of South America, specifically the Andes and the Amazon, create both challenges and opportunities for people living in those regions?' Facilitate a class discussion, encouraging students to use key vocabulary and cite specific examples.

Frequently Asked Questions

Why is the Atacama Desert so dry if it is close to the Pacific Ocean?

The Atacama sits on the leeward side of the Andes relative to Atlantic moisture, and the cold Humboldt Current offshore suppresses evaporation and cloud formation from the Pacific. These two factors combine to make the Atacama the driest non-polar place on Earth. Some weather stations in the region have recorded no measurable rainfall for decades.

What makes the Amazon Basin so biodiverse?

The Amazon's biodiversity reflects several geographic factors: consistently high rainfall, warm temperatures, geographic stability over millions of years, and a large area of connected habitat. These conditions allowed species to evolve in place over long periods without major climate disruptions. The region also contains many microhabitats due to variation in soils, flooding regimes, and canopy structure.

How do the Andes affect weather patterns across South America?

The Andes act as a barrier to atmospheric circulation, blocking moisture-laden air from the Amazon from reaching the Pacific coast. On the eastern slopes, warm, wet conditions support tropical forests. On the western slopes, air descends dry, creating desert conditions. The mountains also trigger orographic precipitation that feeds major river systems, including the Amazon itself.

How does active learning help students grasp South American physical geography?

Students who annotate elevation profiles and correlate them with climate data develop a spatial mental model that sticks much longer than passive map reading. Working through a cross-section analysis where students must make predictions and then check them against data builds genuine geographic reasoning. The physical geography of South America is visually striking, and giving students time to examine photographs and maps before explanations builds durable spatial understanding.