Lesson 6.2 - Biomes

Lesson 6.2 — Biomes Definition: A biome is a large region on Earth that has similar climate, plants, and animals. Each biome results from the interaction of: • • Biotic factors (living things – plants, animals, microorganisms) Abiotic factors (non-living – sunlight, temperature, water, soil, wind) Tropical Rainforest • • • • • • Climate: Warm all year (> 2 m rain per year). Soil: Nutrient-poor (due to heavy rain washing minerals away). Plants: Layers of trees – emergent, canopy, understory. Large flat leaves and shallow roots. Animals: Most diverse biome; highly specialized species (monkeys, birds, frogs, insects). Examples: Amazon (S. America), Congo (Africa), Australasia, Sundaland. Biotic–Abiotic Link: Warm temps and high rain → thick vegetation and biodiversity. 🌧 Temperate Rainforest • • • • • Climate: Moderate temperature + heavy rainfall. Location: Pacific Northwest (U.S.). Plants: Tall evergreen (cedar, hemlock), conifers (produce seed bearing cones).Moss covers the floor(forest floor). Animals: Moisture-loving amphibians (salamanders, frogs). Biotic–Abiotic Link: Constant rain keeps evergreen trees and mossy habitat. Tropical Dry Forest • • • • Climate: Warm all year but rainfall is seasonal. Plants: Deciduous trees lose leaves in dry season; deep roots and waxy leaves. Animals: Estivate or migrate during dry season. Biotic–Abiotic Link: Seasonal rain controls leaf growth and animal behavior. Savanna • • • • Climate: Warm with distinct wet and dry seasons; less rain than forest. Plants: Grasses with scattered trees; deep roots, thick bark and bark leaves during wet seasons. Animals: Migrate for water or burrow in dry months. Abiotic factors: Fires and wind limit tree growth. 🏜 Desert • • • • • • Rain: < 25 cm per year. Temp: Hot days, cold nights. Plants: Succulents store water; thick, leathery , spines instead of leaves; deep roots. Animals: Nocturnal; obtain water from food; large ears release heat. Did You Know? Cactus spines are modified leaves; photosynthesis in green stems. Biotic–Abiotic Link: Extreme dry climate → drought-tolerant life. Grasslands (Prairies) • • • • • • Climate: Moderate rain, hot summers, cold winters. Features: Droughts and fires common; grasses grow from base and regrow. Soil: Rich in nutrients → used for farming. Plants: Tall grasses (2 m high) with deep roots (> 1 m). Animals: Adapt to open areas (little cover). Biotic–Abiotic Link: Rain and fire patterns maintain grasses. Tundra • • • • • • Location: High latitudes (Northern Hemisphere). Climate: Long dark cold winters; short cool summers.Harsh winds. Soil: Nutrient-poor; permafrost (frozen layer). Plants: Mosses, lichens, small shrubs. No tall trees.(freezing limit plant growth). Animals: Caribou, arctic fox, birds migrate in summer. Biotic–Abiotic Link: Frozen soil and cold limit plant growth and biodiversity. Taiga (Boreal Forest)(from worksheet) • • • • • • Location: Between Tundra and Temperate Forest (Canada, Russia, Scandinavia). Climate: Cold long winters, short summers (–65 °C to 20 °C). Snow 300–900 mm/year. Plants: Coniferous evergreen trees (pine, fir, spruce). o Needle-shaped leaves with waxy coat → less water loss. o Cone shape → snow slides off. o Shallow roots → absorb surface water. o Dark green needles → absorb sunlight. Animals: Bears, wolves, moose (hibernate or thick fur). Comparison with Tundra: Taiga has more rain (30–85 cm vs Tundra < 25 cm) and tall trees. Biotic–Abiotic Link: Cold snowy climate supports evergreens adapted to freezing. Summary of Main Biomes Biome Tropical Rainforest Temp & Rain Hot + wet Plants Animals Key Feature Large leaves Specialized Highest biodiversity Temperate Rainforest Cool + wet Evergreen conifers Amphibians Mossy floor Tropical Dry Forest Warm + seasonal rain Deciduous trees Migrating animals Waxy leaves Savanna Warm + dry/wet season Grasses + few trees Migrate/burrow Frequent fires Desert Hot day, cold night Succulents Nocturnal animals Very dry Grassland Moderate rain Grasses Grazing herbivores Fertile soil Taiga Cold + snow Conifers Hibernating mammals Evergreen forest Tundra Extremely cold Moss, lichens Migrating animals Permafrost Key Sentence to Memorize: “Each biome’s ecosystem results from interactions between biotic factors (plants & animals) and abiotic factors (climate, soil, water, temperature).”