Biomes are large ecological regions defined by climate, dominant plants, and the animals adapted to live there. They help scientists organize Earth’s huge variety of ecosystems into patterns that can be mapped and studied. Temperature and precipitation are the main controls, so similar biomes can appear on different continents.
Understanding biomes matters because it helps explain biodiversity, agriculture, conservation, and how climate change can shift habitats.
Key Facts
- Biome patterns are mainly controlled by average temperature and annual precipitation.
- Tundra has very cold temperatures, low precipitation, permafrost, mosses, lichens, and low shrubs.
- Taiga, also called boreal forest, is dominated by cone-bearing trees such as spruce, fir, and pine.
- Deserts usually receive less than 25 cm of precipitation per year.
- Tropical rainforests are warm year-round and often receive more than 200 cm of rain per year.
- Net primary productivity depends on photosynthesis and can be summarized as NPP = GPP - R, where GPP is gross primary productivity and R is plant respiration.
Vocabulary
- Biome
- A biome is a large region of Earth with a characteristic climate, plant life, and animal life.
- Permafrost
- Permafrost is ground that remains frozen for at least two consecutive years, common in tundra regions.
- Precipitation
- Precipitation is water that falls from the atmosphere as rain, snow, sleet, or hail.
- Biodiversity
- Biodiversity is the variety of living organisms in an area, including species, genes, and ecosystems.
- Adaptation
- An adaptation is an inherited trait that helps an organism survive and reproduce in its environment.
Common Mistakes to Avoid
- Confusing weather with climate is wrong because biomes are classified by long-term averages, not by the conditions on a single day.
- Assuming every desert is hot is wrong because deserts are defined by low precipitation, and some deserts are cold.
- Placing tropical rainforests only where it is rainy is incomplete because they also require consistently warm temperatures throughout the year.
- Ignoring latitude and elevation is a mistake because both affect temperature, so high mountains can have tundra-like conditions even at lower latitudes.
Practice Questions
- 1 A region receives 18 cm of precipitation per year and has sparse shrubs and drought-resistant plants. Based on precipitation alone, which biome is most likely, and why?
- 2 A temperate forest receives 90 cm of rain per year, while a grassland receives 45 cm per year. How many more centimeters of annual precipitation does the forest receive, and what is the ratio of forest precipitation to grassland precipitation?
- 3 Two locations are at the same latitude, but one is at sea level and the other is high in the mountains. Explain why the mountain location may support a different biome even though both receive similar sunlight.