Recording-2025-09-15T14:38:31.997Z

Biomes: Temperature, Precipitation, and Zonation

• Setup for activity

  • Students to form pairs and work on a handout about different biomes.
  • Task: determine where each biome fits on a temperature vs. precipitation diagram; discuss daytime vs. nighttime temperatures and seasonal differences.
  • Reminder: the class should fill the entire triangular/diagonal space with all 10 biomes; some biomes may produce non-rectangular shapes (e.g., long, skinny windows for narrow combinations of temp and precip; some may be both cold and hot; some may be both dry and wet).
  • Use prior experiences and neighbour discussions to compare real places with the biomes (desert, rainforest, etc.).
  • Example prompts given: tropical dry forest has wet and dry seasons; deserts can be cold at night; temperate rainforest vs. tropical rainforest precipitation differences.

• Biome identification on maps and common references

  • The teacher shows a biome distribution map with color-coded biomes (e.g., tundra, boreal forest/taiga, grassland, desert, tropical rainforest, temperate rainforest, tropical dry forest, deciduous forest, savanna, chaparral).
  • Note: the teacher mentions a common issue where tropical rainforest and tropical dry forest are sometimes merged in maps.
  • Discussion on how biomes are arranged on the map: latitude-based patterns become evident with deserts and savannas near 20–30°N/S, rainforests near the equator, boreal forests in higher latitudes, tundra toward the poles.

• Key concepts: latitudinal zonation and altitudinal zonation

  • Latitudinal zonation (global pattern)
  • At a given latitude, a characteristic biome tends to occur; moving north or south from the equator leads to a change in biome due to shifts in temperature and precipitation.
  • The concept is known as latitudinal zonation.
  • Example discussion: East Africa can have savannah despite nearby rainforest due to mountains creating rain shadows.
  • Visual illustration: as you move away from the equator, typical progression of biomes is rainforest → tropical dry forest/desert → savanna/grassland → chaparral/deciduous forest → boreal forest → tundra (with regional variation).
  • Altitudinal zonation (elevation-based pattern)
  • On tall mountains, vegetation changes with elevation in a way that mirrors latitudinal patterns, even within the same latitude.
  • Base (low elevation) in tropics: rainforest; mid-elevations: boreal-like or temperate-like vegetation; higher elevations: shrublands and stunted trees; near the top: no vegetation (ice cap at the very top if tall enough).
  • This is not a separate biome system; it’s a vertical echo of latitudinal patterns due to decreasing temperature with elevation.

• Detailed biome mapping and reasoning (temperature vs. precipitation considerations)

  • Tropical rainforest vs. tropical dry forest
  • Tropical rainforest: high precipitation and warm temperatures; high overall rainfall.
  • Tropical dry forest: warm but with more pronounced dry season; precipitation is still relatively high but with a distinct dry period.
  • Temperate rainforest vs. tropical rainforest
  • Temperate rainforest: high precipitation but cooler temperatures than tropical rainforest; located away from the equator where temperatures are moderated.
  • Desert and savanna
  • Deserts: low precipitation; can be hot or cold depending on latitude; deserts can cool at night due to low moisture and clear skies.
  • Savanna: warm with moderate to low precipitation; contains scattered trees; more precip than desert, supporting more vegetation than desert.
  • Grasslands and chaparral
  • Grasslands: intermediate precipitation; dynamics depend on region; often found between deserts and forests.
  • Chaparral: warm with relatively low precipitation; evergreen shrubs; drought-adapted.
  • Deciduous forest and boreal forest (taiga)
  • Deciduous forest: moderate to high precipitation; warm summers and cool winters; broadleaf trees that shed leaves.
  • Boreal forest (taiga): cooler temperatures; lower precipitation relative to deciduous forests; coniferous trees dominate.
  • Tundra
  • Very cold, low precipitation; minimal or no trees; short growing season.

• Biome placement heuristics from the class activity

  • Top-right and