In AP Environmental Science, a biome is a large geographic region defined by its climate (mainly temperature and precipitation) and the characteristic plant and animal communities that have adapted to that climate, such as taiga, tropical rainforest, desert, and tundra.
A biome is a large chunk of the planet that shares a climate and, because of that climate, shares the same general types of plants and animals. The key idea (EK ERT-1.B.1) is that climate comes first. Temperature and precipitation set the rules, and the living communities are whatever can survive those rules. That's why a desert in Africa and a desert in North America look so similar even though they're oceans apart. Same climate, same adaptations.
The AP CED names nine major terrestrial biomes you should be able to recognize (EK ERT-1.B.2): taiga, temperate rainforest, temperate seasonal forest, tropical rainforest, shrubland, temperate grassland, savanna, desert, and tundra. Where each one shows up around the globe depends on a mix of climate, geography, latitude, altitude, nutrient availability, and soil (EK ERT-1.B.3). Latitude is the big one. Tropical rainforests cluster near the equator where it's warm and wet, while tundra sits at high latitudes where it's cold and dry.
Biomes are Topic 1.2 in Unit 1 (The Living World: Ecosystems), and they anchor learning objective AP Enviro 1.2.A: describe the global distribution and principal environmental aspects of terrestrial biomes. This is foundational. Unit 1 is where you build the vocabulary for everything that follows, and biomes connect climate to the living world. If you can read a temperature-and-precipitation graph and name the biome, you've got a tool that pays off all year, especially when climate change enters the picture in later units.
Climate (Unit 1)
Climate is the cause and a biome is the effect. Temperature and precipitation are the two dials that decide which biome you get, which is why two climate numbers are often enough to pin down a biome on the exam.
Ecosystem (Unit 1)
A biome is the big-picture version of an ecosystem. An ecosystem is one community of organisms plus their environment in a specific place, while a biome groups together all the ecosystems worldwide that share a climate and look alike.
Biodiversity (Unit 1)
Different biomes hold wildly different amounts of biodiversity. Tropical rainforests pack in the most species, while tundra and desert hold far fewer, which matters when you predict where climate change will cause the biggest losses.
Elevation zone (Unit 1)
Climbing a mountain mimics traveling toward the poles. As altitude rises, you pass through biome-like zones in the same order you'd hit moving from the equator to the tundra, because both cool down as you go.
Multiple-choice questions love giving you a set of clues, short growing season, permafrost, shallow-rooted plants, and asking which biome and which climate factor explains it (that one's tundra, driven by cold temperature). You'll also see latitude questions, since biome distribution tracks latitude closely. Climate-change framing is everywhere: expect stems asking which biome shifts northward as the planet warms, or which biome loses the most biodiversity if temperatures jump a few degrees. On FRQs, biomes show up as the setting for free-response prompts (a 2025 FRQ centered on the Serengeti, a savanna), so be ready to use biome characteristics as evidence rather than just name the biome.
A biome is huge and climate-defined, spanning multiple continents (all of Earth's deserts make up the desert biome). An ecosystem is local and specific, one community of living things interacting with their physical environment in a single place. Think of a biome as the category and an ecosystem as one real example inside it.
A biome is a large region defined by climate, and its plant and animal communities are whatever can survive that climate (EK ERT-1.B.1).
The nine AP terrestrial biomes are taiga, temperate rainforest, temperate seasonal forest, tropical rainforest, shrubland, temperate grassland, savanna, desert, and tundra (EK ERT-1.B.2).
Temperature and precipitation are the two factors that most determine which biome forms in a given place.
Biome distribution follows latitude: tropical rainforest near the equator, tundra near the poles.
Climbing in altitude produces the same sequence of biomes as moving toward the poles, because both get colder.
Climate change shifts biomes (often poleward) and threatens biodiversity most in species-rich biomes like tropical rainforests.
A biome is a large geographic region defined by its climate, mainly temperature and precipitation, along with the plant and animal communities adapted to that climate. The AP CED lists nine: taiga, temperate rainforest, temperate seasonal forest, tropical rainforest, shrubland, temperate grassland, savanna, desert, and tundra.
No. A biome is much larger and grouped by climate, so all the world's deserts together form the desert biome. An ecosystem is a single local community of organisms interacting with their physical environment, making it one specific example found inside a biome.
Use the two values together. Hot and wet points to tropical rainforest, cold with permafrost and a short growing season points to tundra, and warm with very little rain points to desert. The exam often gives you exactly these clues and asks you to name the biome.
As average temperatures rise, biomes shift, often northward toward cooler latitudes, and the species that can't move or adapt fast enough are lost. Biodiversity-rich biomes like tropical rainforests tend to lose the most species when temperatures climb a few degrees.
Latitude controls how much solar energy a region gets, which drives temperature and rainfall patterns. That's why tropical rainforests cluster near the warm, wet equator and tundra sits at cold, dry high latitudes.