Biomes and Ecosystems Overview

Biomes Overview

• Biomes are broad categories of ecosystems sharing common traits.
• Major examples include Desert, Rainforest, and Tundra.
• Biome identity is largely determined by plant species and climate.

Climate Influence on Biomes

• Climate is the primary factor affecting the location of biomes.
• Key climate influencers:
  • Latitude affects energy input and sun angle.
  • Continental Position shapes climate through land and sea interaction.
  • Altitude impacts temperature due to adiabatic cooling.
  • Orographic Effect changes precipitation patterns based on geography.

Soil Characteristics

• Soil is a complex mixture impacting biomes, composed of living and non-living materials.
• Influencing factors include local geology, climate, and the biotic community.
• Soil classification is based on horizons:
  • O horizon: Organic material layer.
  • A horizon: Mixture of minerals and organic matter.
  • B horizon: Clay and leached materials containing plant roots.
  • C horizon: Weathered parent material.

Tropical Rainforest

• Found within 20° latitude of the equator.
• Experiences little temperature fluctuation and receives 2,000 - 4,000 mm of rainfall annually.
• Rapid soil nutrient leaching occurs; mycorrhizae assist in nutrient acquisition.
• Heightened biodiversity with arboreal animals and diverse insect populations.

Tropical Dry Forest

• Located between 10° and 25° latitude, seasonal climate with richer soils than rainforests.
• Subject to deforestation for agriculture.
• Shares flora and fauna with tropical rainforests.

Tropical Savanna

• Positioned within 10° to 20° latitude with wet and dry seasonal alternation.
• Drought conditions lead to wildfires; soils have low water retention.
• Characterized by two-dimensional landscapes due to livestock pressures.

Desert Biome

• Predominant at 30° N and 30° S latitude, covering 20% of Earth's land.
• Water loss exceeds precipitation; soils retain low organic matter.
• Low animal abundance with high biodiversity due to adaptive behaviors.

Chaparral Biome

• Found in Mediterranean climates across all continents except Antarctica.
• Cool and moist off-seasons with hot, dry summers.
• Soil is fragile yet moderately fertile; vegetation includes fire-resistant plants.

Temperate Grassland

• Extensively distributed with annual rainfall between 300 - 1,000 mm.
• Experiences periodic droughts; soils are nutrient-rich and deep.
• Dominated by herbaceous plants; large grazing animals common, e.g., bison and cattle.

Temperate Forest (Old Growth)

• Majority located between 40° and 50° latitude with rainfall of 650 - 3,000 mm.
• Fertile soils promote long growing seasons dominated by deciduous and coniferous plants.

Boreal Forest (Taiga)

• Restricted to the Northern Hemisphere, covering 11% of Earth's land area.
• Features thin, acidic soils with low fertility and is dominated by evergreen conifers.
• Relatively high density of animal populations.