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Unlock This CourseA biome is a large-scale ecosystem characterised by distinctive plant and animal communities that have adapted to the climate and environmental conditions of a particular region. The distribution of biomes across the world follows clear patterns that are mainly controlled by climate, especially temperature and rainfall.
Key Definitions:
Biomes are arranged in bands around the Earth, following latitude lines. This happens because climate changes predictably from the equator to the poles. Hot, wet conditions near the equator support tropical rainforests, whilst cold, dry conditions near the poles create tundra biomes.
There are several major biomes distributed across the world, each with unique characteristics shaped by climate, soil and geography. Understanding these biomes helps us see how life adapts to different environments.
Found near the equator in places like the Amazon Basin, Central Africa and Southeast Asia. These biomes have high temperatures (25-30°C) and heavy rainfall (over 2000mm annually) throughout the year.
Dense, multi-layered forests with broad-leaved evergreen trees. High biodiversity with species like mahogany, rubber trees and countless epiphytes.
Incredibly diverse animal life including jaguars, monkeys, parrots and millions of insect species. Many animals are adapted for life in trees.
Deforestation for agriculture, logging and urban development threatens these biomes. Indigenous communities have traditionally lived sustainably here.
Located around 30° north and south of the equator, deserts receive less than 250mm of rainfall annually. The Sahara, Kalahari and Australian deserts are major examples.
Sparse vegetation adapted to drought, including cacti, succulents and drought-resistant shrubs. Plants have waxy coatings and water storage adaptations.
Animals adapted to extreme conditions like camels, desert foxes and reptiles. Many are nocturnal to avoid daytime heat.
Nomadic herding, oasis agriculture and increasingly, solar energy production. Tourism also brings economic opportunities.
The Amazon covers 5.5 million km² across nine countries, with 60% in Brazil. It contains 10% of the world's biodiversity and produces 20% of the world's oxygen. However, deforestation rates have increased dramatically, with cattle ranching and soy farming being major causes. The Brazilian government has implemented protected areas and monitoring systems, but illegal logging continues to threaten this vital biome.
Found in continental interiors like the Great Plains of North America and the Pampas of South America. These areas have moderate rainfall (300-750mm) and experience hot summers and cold winters.
Dominated by grasses rather than trees due to limited rainfall and periodic fires. Fertile soils make these areas ideal for agriculture. Natural grasslands support grazing animals like bison and antelope.
The world's largest biome, stretching across northern Canada, Alaska and Siberia. Characterised by long, cold winters and short, mild summers with moderate precipitation.
Dominated by coniferous trees like spruce, fir and pine. These needle-leaved trees are adapted to cold conditions and acidic soils.
Animals include bears, wolves, lynx and migratory birds. Many species hibernate or migrate to survive harsh winters.
Major source of timber, paper and pulp. Also important for fur trapping and increasingly for eco-tourism.
The distribution of biomes is primarily controlled by climate, which varies predictably with latitude, altitude and distance from oceans. Understanding these patterns helps explain why certain biomes occur where they do.
Temperature decreases with increasing latitude and altitude. This creates distinct zones: tropical biomes near the equator, temperate biomes in mid-latitudes and polar biomes near the poles.
The angle of the sun's rays changes with latitude, creating temperature gradients. Equatorial regions receive direct sunlight year-round, whilst polar regions receive oblique rays and experience seasonal darkness.
Rainfall distribution is influenced by global wind patterns, ocean currents and topography. Areas with high rainfall support forests, whilst low rainfall areas develop grasslands or deserts.
Found in five regions worldwide: the Mediterranean Basin, California, Chile, South Africa and southwestern Australia. This biome experiences hot, dry summers and mild, wet winters. Vegetation includes drought-resistant shrubs and trees like olive and cork oak. Human activities have heavily modified these areas through agriculture (vineyards, olive groves) and urban development. Fire management is crucial as natural fires help maintain the ecosystem.
Human activities have significantly altered biome distribution and characteristics. Agriculture, urbanisation and resource extraction have transformed natural ecosystems, often reducing biodiversity and ecosystem services.
Many natural biomes have been converted to farmland. Temperate grasslands are now major grain-producing regions, whilst tropical forests are cleared for cattle ranching and crop production.
Agriculture provides food security and economic development. Sustainable farming practices can maintain soil fertility and support wildlife corridors within agricultural landscapes.
Protected areas, national parks and biosphere reserves help preserve natural biomes. International agreements like the Convention on Biological Diversity promote biome conservation globally.
Climate change is altering biome boundaries and characteristics. Rising temperatures and changing precipitation patterns are shifting biome distributions poleward and upward in elevation. This creates challenges for both wildlife conservation and human communities dependent on ecosystem services.
Conservation strategies must adapt to changing conditions. This includes creating wildlife corridors, assisted migration of species and developing climate-resilient agricultural systems that work with natural biome characteristics.