Climates & Biomes PDF

Biomes are generalized categories of ecosystems with common characteristics. Examples: Desert, Large- Rainforest, Tundra Scale Biomes are usually Distributio recognized by ns cha...

Biomes are generalized categories of ecosystems with common characteristics. Examples: Desert, Large- Rainforest, Tundra Scale Biomes are usually Distributio recognized by ns characteristics of the plant species. The primary determining factor in biome location is climate. Earth’s Major Biome Types Global Rainfall Totals Climates and Biomes  Factors Influencing Climate Latitude Continental Position Altitude Orographic Effect  Factors Influencing Climate Latitude Unequal energy input Angle of Sun’s rays The angle of earth’s axis of rotation, relative to the sun, changes seasonally. Hadley Cells form in tropical latitudes Coriolis effect causes winds to be deflected as the move across earth’s surface Coriolis effect also leads to ocean basins moving in circular rotations (gyres) Adiabatic cooling leads to lower temperatures at higher elevations Orographic Effect  Soil : Foundation of Terrestrial Biomes Soil is a complex mixture of living and non-living material. The composition of soil is influenced by: local rocks and minerals climate the biotic community Classification based on vertical layering (soil horizons).  Soil Horizons O horizon: Layer of freshly fallen organic material - most superficial layer. A horizon: Mixture of mineral particles and organic matter. B horizon: Clay and other materials leached from A horizon - often contains plant roots. C horizon: Weathered parent material. Soil Profile Organ Pipe Cacti prefer the course soil found on slopes Biomes of Western Hemisphere Biomes of Eastern Hemisphere  Most occur within 20o latitude of equator. Little temperature variation between months. Annual rainfall of 2,000 - Tropical 4,000 mm relatively Rainfores evenly distributed. ts Quickly leaches soil nutrients. Mycorrhizae help gather nutrients. Trees add vertical dimension. Tropical Rainforest Climate Tropical Rainforest Three-Dimensional Layered Vegetation Tropical Rainforest Densely Vegetated Dark Interior Rainforest Epiphytes Arboreal animals are abundant in rainforests Hyper-diverse insect community  Usually located between 10o - 25o latitude. Climate more seasonal than tropical rainforest. Soils generally richer in Tropical nutrients, but vulnerable Dry to erosion. Forest Shares many animal and plant species with tropical rainforests. Heavily settled by humans with extensive clearing for agriculture. Tropical Dry Forest  Most occur north and south of tropical dry forests within 10o - 20o of the equator. Climate alternates between wet / dry seasons. Drought associated with dry season leads to Tropical lightning-caused Savanna wildfires. Soils have low water permeability. Saturated soils keeps trees out. Landscape is more two- dimensional with increasing pressure to produce livestock. Tropical Savanna Climate Tropical Savanna Vegetation Tropical Savanna Animals Large Migrating Herds High Abundance of Herbivorous Insects Desert Major bands at 30o N and 30o S latitude. Occupy about 20% of earth’s land surface. Water loss usually exceeds precipitation. Soil usually extremely low in organic matter. Plant cover ranges from sparse to absent. Animal abundance low, but biodiversity may be high. Strong behavioral adaptations. Desert  Chaparral Found in Mediterranean climates Occur in all continents except Antarctica. Climate cool and moist in fall, winter, and spring, but can be hot and dry in summer. Fragile soils with moderate fertility. Trees and shrubs typically evergreen. Fire-resistant plants due to fire regime. Mediterranean Woodland and Shrubland Manzanita Regrowth Temperate Grassland Extremely widespread distribution. Annual rainfall 300 - 1,000 mm. Experience periodic droughts. Soils tend extremely nutrient rich and deep. Thoroughly dominated by herbaceous vegetation. Large roaming ungulates. Bison vs. cattle Temperate Grassland Temperate Forest (Old Growth) Majority lie between 40o and 50o latitude. Rainfall averages 650 - 3,000 mm. Fertile soils Long growing seasons dominated by deciduous plants. Short growing seasons dominated by conifers. Biomass production can be very high. Temperate Forest (Old Growth) Boreal Forest (Taiga) Confined to Northern Hemisphere. Covers 11% of earth’s land area. Thin, acidic soils low in fertility. Generally dominated by evergreen conifers. Relatively high animal density. Boreal Forest (Taiga) Tundra Covers most of lands north of Arctic Circle. Climate typically cool and dry with short summers. 200 - 600 mm precipitation. Low decomposition rates. Supports substantial numbers of native mammals. Tundra