World Geography Unit 6 Review: Geography, Climate & Ecosystems

Key Geographic Features

• Andes Mountains extend 4,300 miles along the western coast of South America (Chile, Peru, Ecuador, Colombia)
• Amazon River is the world's second-longest river at 4,000 miles long and drains the Amazon Basin
  • Flows through Peru, Colombia, and Brazil before emptying into the Atlantic Ocean
• Atacama Desert in northern Chile and southern Peru is the driest non-polar desert in the world
  • Receives less than 0.1 inches of rain per year on average
• Patagonia is a sparsely populated region at the southern end of South America shared by Argentina and Chile
  • Characterized by grasslands, deserts, and the southern portion of the Andes Mountains
• Pampas are fertile lowlands in Argentina and Uruguay that support extensive cattle ranching and agriculture (soybeans, wheat)
• Caribbean Islands include the Greater Antilles (Cuba, Hispaniola, Jamaica, Puerto Rico) and Lesser Antilles (Virgin Islands, Barbados)
  • Formed by volcanic activity and tectonic plate movement
• Isthmus of Panama connects North and South America and separates the Caribbean Sea from the Pacific Ocean
  • Constructed Panama Canal facilitates shipping between the two oceans

Climate Zones and Patterns

• Equatorial climate zone near the equator (Amazon Basin) characterized by high temperatures and rainfall year-round
  • Average temperature around 80°F (27°C) with little seasonal variation
  • Annual rainfall often exceeds 80 inches
• Tropical wet and dry climate zones (Central America, Caribbean) have distinct wet and dry seasons
  • Wet season occurs during summer months when the Intertropical Convergence Zone (ITCZ) brings heavy rainfall
  • Dry season occurs during winter months when the ITCZ shifts away and trade winds bring drier conditions
• Subtropical climate zones (southeastern Brazil, northern Argentina) have hot, humid summers and mild winters
  • Located between 20-35° latitude on eastern sides of continents
• Mediterranean climate zone in central Chile characterized by mild, wet winters and hot, dry summers
  • Influenced by cold ocean currents (Humboldt Current) that moderate temperatures and create coastal fog
• Midlatitude climate zones (Patagonia) have cool to cold winters and mild to warm summers
  • Influenced by westerly winds and ocean currents
• Highland climate zones in the Andes Mountains have cooler temperatures due to high elevation
  • Temperature decreases about 3.5°F (2°C) for every 1,000 feet of elevation gain

Major Ecosystems and Biomes

• Amazon rainforest is the world's largest tropical rainforest and covers much of the Amazon Basin
  • High biodiversity with millions of plant and animal species, many endemic
  • Dense vegetation in multiple layers (emergent, canopy, understory, forest floor)
• Cerrado is a tropical savanna ecosystem in central Brazil characterized by grasslands with scattered trees and shrubs
  • Supports high biodiversity and is threatened by agricultural expansion (soybeans, cattle ranching)
• Pantanal is the world's largest tropical wetland located mostly in Brazil with portions in Bolivia and Paraguay
  • Seasonal flooding supports diverse aquatic plants and animals (capybara, jaguar, giant river otter)
• Valdivian temperate rainforest in southern Chile is a unique ecosystem with high endemism
  • Dominated by evergreen broadleaf trees and receives high rainfall from westerly winds
• Mangrove forests along Caribbean and Pacific coasts provide important habitat for fish and protect shorelines from erosion
  • Adapted to saltwater conditions with aerial roots and salt-excreting leaves
• Alpine tundra ecosystems in the high Andes Mountains have low-growing vegetation adapted to cold temperatures and strong winds
  • Characterized by cushion plants, mosses, and lichens
• Atacama Desert has sparse vegetation adapted to extreme aridity, including cacti and drought-resistant shrubs
  • Some areas have no recorded rainfall for hundreds of years

Natural Resources and Their Distribution

• Mineral resources are abundant in the Andes Mountains, including copper (Chile, Peru), silver (Mexico, Peru), and lithium (Bolivia, Chile, Argentina)
  • Extracted through mining operations that can have significant environmental impacts
• Oil and natural gas reserves are found in Venezuela, Mexico, Brazil, and Argentina
  • Offshore drilling occurs in the Gulf of Mexico and along the coasts of Brazil and Argentina
• Hydroelectric potential is high in the Amazon Basin and Andes Mountains due to numerous rivers and high elevations
  • Large dams (Itaipu Dam in Brazil/Paraguay) generate electricity but can disrupt river ecosystems and displace communities
• Agricultural resources include fertile soils in the Pampas region of Argentina and Uruguay, supporting cattle ranching and crop production (soybeans, wheat, corn)
  • Intensive agriculture can lead to soil degradation and deforestation
• Timber resources are abundant in the Amazon rainforest and temperate forests of Chile and Argentina
  • Logging and forest clearing for agriculture are major drivers of deforestation
• Fisheries are important along the Pacific coast, especially in Peru and Chile, which are among the world's leading fish producers (anchovies, sardines)
  • Overfishing and El Niño events can disrupt fish populations and affect the fishing industry

Environmental Challenges and Conservation

• Deforestation is a major issue in the Amazon rainforest, driven by logging, cattle ranching, and soybean cultivation
  • Leads to habitat loss, biodiversity decline, and carbon emissions
  • International efforts (REDD+) aim to reduce deforestation through financial incentives
• Water pollution from mining, oil extraction, and agricultural runoff affects rivers and coastal areas
  • Mercury used in gold mining contaminates fish and poses health risks to communities
• Air pollution in major cities (Mexico City, São Paulo) from vehicle emissions and industrial activities
  • Contributes to respiratory illnesses and environmental degradation
• Overexploitation of natural resources, such as overfishing and unsustainable logging, threatens ecosystems and livelihoods
  • Establishment of protected areas and sustainable management practices aim to address these issues
• Climate change impacts, including sea-level rise, coral bleaching, and altered weather patterns, affect coastal areas and ecosystems
  • Adaptation measures and international agreements (Paris Agreement) seek to mitigate and adapt to climate change
• Conservation efforts include the creation of national parks (Galápagos Islands in Ecuador), marine protected areas, and indigenous reserves
  • Balancing conservation with economic development and resource use remains a challenge

Human-Environment Interaction

• Agriculture has transformed natural landscapes, particularly in the Amazon Basin and Pampas region
  • Slash-and-burn agriculture in the Amazon leads to deforestation and soil degradation
  • Intensive cattle ranching and soybean cultivation in the Pampas alter grassland ecosystems
• Urbanization and the growth of megacities (Mexico City, São Paulo, Buenos Aires) create environmental pressures
  • Increased demand for resources, energy, and waste management
  • Urban sprawl encroaches on natural habitats and agricultural lands
• Infrastructure development, such as roads and dams, fragments habitats and alters river systems
  • Construction of the Trans-Amazonian Highway in Brazil opened up the Amazon rainforest to settlement and resource extraction
• Ecotourism has emerged as a way to promote conservation and sustainable development
  • Galapagos Islands in Ecuador and Iguazu Falls in Argentina/Brazil attract visitors and support local economies
  • Balancing tourism with environmental protection is an ongoing challenge
• Indigenous communities have long-standing relationships with the environment and play a role in conservation
  • Traditional ecological knowledge and land management practices contribute to biodiversity conservation
  • Conflicts arise over resource use and land rights, particularly in the Amazon region

Impact on Culture and Economy

• Agriculture is a significant component of many Latin American economies, particularly in Brazil, Argentina, and Mexico
  • Cash crops (coffee, bananas, sugarcane) are important exports and shape local cultures
  • Subsistence farming remains common in rural areas and among indigenous communities
• Extractive industries, such as mining and oil production, are major economic drivers but can lead to social and environmental conflicts
  • Dependence on resource exports leaves countries vulnerable to global price fluctuations
• Tourism is a growing industry, with cultural and natural attractions drawing visitors from around the world
  • Mayan ruins in Mexico and Central America, Machu Picchu in Peru, and the Amazon rainforest are popular destinations
  • Tourism can provide economic opportunities but also lead to cultural commodification and environmental degradation
• Environmental degradation and climate change disproportionately affect marginalized communities, including indigenous peoples and the rural poor
  • Loss of traditional livelihoods, displacement, and health impacts exacerbate existing inequalities
• Conservation efforts and sustainable development initiatives seek to balance economic growth with environmental protection
  • Payments for ecosystem services (PES) programs incentivize conservation by compensating landowners for maintaining natural areas
  • Fair trade certifications for coffee and other products aim to support small-scale producers and promote sustainable practices

Case Studies and Regional Highlights

• The Great American Interchange refers to the migration of species between North and South America after the formation of the Isthmus of Panama about 3 million years ago
  • Armadillos, opossums, and porcupines moved north, while bears, cats, and horses moved south
  • Contributed to the extinction of many South American species and altered ecosystems
• The Galápagos Islands in Ecuador are a UNESCO World Heritage Site and a unique example of evolutionary processes
  • Home to endemic species such as the Galápagos tortoise, marine iguana, and Darwin's finches
  • Charles Darwin's observations of the islands' species during his voyage on the HMS Beagle contributed to the development of his theory of evolution by natural selection
• The Cerrado biome in Brazil is a global biodiversity hotspot but is threatened by agricultural expansion
  • Rapid conversion of native vegetation to soybean fields and cattle pastures
  • Efforts to create protected areas and promote sustainable land use practices aim to balance conservation and economic development
• The Andes Mountains play a crucial role in the water cycle and climate of South America
  • Melting glaciers and high-altitude wetlands (páramos) provide water for downstream communities and ecosystems
  • Climate change is leading to glacial retreat and altered water availability, with implications for agriculture, hydropower, and urban water supplies
• The Caribbean region is highly vulnerable to hurricanes and other extreme weather events
  • Hurricanes cause damage to infrastructure, agriculture, and ecosystems, with long-lasting impacts on local communities
  • Climate change is expected to increase the intensity and frequency of hurricanes in the region, exacerbating existing vulnerabilities