Terrestrial Biomes
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Terrestrial Biomes IB Syllabus: 2.4.1-2.4.2 AP Syllabus Ch 6 Video – planet Earth – pole to pole Syllabus Statements • 2.4.1: Define the term Biome • 2.4.2: Explain the distribution, structure and relative productivity of tropical rainforests, deserts, tundra and any other biome vocabulary • Biome • Latitude What is a biome? • World climate is variable – Differences in temperature and precipitation – Different climates Different communities • Biomes = Regions of the earth characterized by specific climates and community types • Remember they cross national boundaries • Real biomes do not have sharply defined boundaries. Ecotones = Transitional zones • Biomes not uniform, instead a mosiac of patches – Vary in microclimate, soil types, disturbances Tropic of Cancer Equator Tropic of Capricorn Arctic tundra (polar grasslands) Desert Boreal forest (taiga), evergreen coniferous forest (e.g., montane coniferous forest) Tropical rain forest, tropical evergreen forest Semidesert, arid grassland Mountains (complex zonation) Temperate deciduous forest Tropical deciduous forest Ice Temperate grassland Tropical scrub forest Dry woodlands and shrublands (chaparral) Tropical savanna, thorn forest Major Terrestrial Biomes 1. Desert 2. Tundra 3. Forests 1. Tropical Rainforest, Tropical deciduous forest 2. Temperate Rainforest, Temperate deciduous 3. Tiaga (Boreal) 4. Grasslands 5. Scrublands 6. Mountains For each Biome you should comment in the distribution, climate (read climatograms), structure, relative productivity and limiting factors Main Biome Effects Altitude Mountain Ice and snow Tundra (herbs, lichens, mosses) Coniferous Forest Latitude Deciduous Forest Tropical Forest Tropical Forest Deciduous Forest Coniferous Forest Tundra (herbs, lichens, mosses) Climate and vegetation vary in a predictable fashion with changes in Altitude and Latitude Polar ice and snow Vegetation changes • Plants in cold regions have traits to limit heat & water loss – Winter dormancy (drop leaves), smaller size, evergreens have needles • Plants in dry areas must lose heat and conserve water – No leaves, water storage, nocturnal activity • Plants in rainforests must get light and remove water – Broad leaves, drip tips, radiate heat 100 30 20 50 10 ft m Tropical rain forest Coniferous forest Deciduous forest Thorn forest Thorn scrub Tall-grass prairie Short-grass prairie Comparison of types, sizes and stratification of species in different terrestrial biomes (structure) Desert scrub Deserts 1. Climate • • • Precipitation < 25 cm / yr – scattered unevenly through year Arid May be Tropical, Temperate and Cold types – always extremes High to moderate insolation 2. Distribution • 30% of earth surface between 30 degrees north and south of the equator – Major ones Saraha (Africa), Gobi (Asia), Mojave (N. america) 3. Structure • • Simple – very little vegetation Most complex is temperate desert which has largest cacti 4. Relative Productivity • Low – limited by water availability World Distribution of Deserts Desert Types • Tropical Deserts • High temp. year round • Little rain, only 1-2 months • Driest places on earth • Few plants • Hard windblown surface: sand & rock • Middle East areas Tropical desert (Saudi Arabia) Desert Types • Temperate Deserts • Day temp. high in summer, low in winter • More precipitation • Sparse vegetation – suculents, cacti, animals • Southern CA (Mojave) Temperate desert (Reno, Nevada) Desert Types • • • • • Cold deserts Winters cold Summers warm to hot Precipitation low Gobi desert, China Polar desert (northwest China) Plant Adaptations Every drop of water counts 1. Wax coated leaves limit transpiration 2. Deep roots tap underground water 3. Wide spread shallow roots gather falling water 4. Drop leaves & dormancy in heat & dry periods 5. Store biomass in seeds Animal Adaptations • Hiding in cool areas during day • Thick skin • Dry feces, concentrated urine • Water from dew & food • Dormancy in heat & drought Red-tailed hawk Producer to primary consumer Gambel's quail Primary to secondary consumer Yucca Jack rabbit Agave Collared lizard Prickly pear cactus Secondary to higher-level consumer All producers and consumers to decomposers Roadrunner Diamondback rattlesnake Darkling beetle Bacteria Fungi Kangaroo rat Human Impacts on Deserts Large desert cities Soil destruction by vehicles and urban development Soil salinization from irrigation Depletion of underground water supplies Land disturbance and pollution from mineral extraction Storage of toxic and radioactive Wastes Large arrays of solar cells and solar collectors used to produce electricity Temperate Grasslands 1. Climate • • • • 2. Precipitation 25-45 cm / yr – enough to grow grass, erratic Semiarid fire, drought, animals prevent tree growth May be Tropical, Temperate Moderate insolation Distribution • • 3. 9% of earth surface Temperate Latitudes – Major onesNA tall grass prairie, steppes, pampas, veldt Grasslands overall up to 40% of earth’s surface Structure • 4. Simple – grasses and herbaceous plants Relative Productivity • Medium to high – high turnover of grasses, rich soils World Distribution of Grasslands Polar Tundra Alpine Tundra Temperate Grassland Tropical Savanna Grassland Types • Temperate grasslands • Vast plains and rolling hills • Summer hot & dry • Winter cold • Sparse, uneven precipitation • Thick fertile soils Temperate grassland (Lawrence, Kansas) Golden eagle Pronghorn antelope Producer to primary consumer Primary to secondary consumer Coyote Grasshopper sparrow Grasshopper Blue stem grass Prairie dog Bacteria Fungi Prairie coneflower Secondary to higher-level consumer All producers and consumers to decomposers Grassland Types • • • • • • Tropical Grasslands Savannas High average temp Moderate rainfall Prolonged drought Herds of herbivores – Grazing & Browsing • Africa, SA, Australia • Migrations in dry season Tropical grassland (savanna) (Harare, Zimbabwe) Herbivore coexistence • • Minimize competition by resource partitioning African animals differ by region & niche 1. Giraffes eat leaves from tree tops 2. Elephants eat leaves and branches further down 3. Gazelles & Wildebeasts eat short grasses 4. Zebras eat longer grass & stems Cape buffalo Wildebeest Beisa oryx Topi Warthog Thompson's gazelle Dry Grassland Waterbuck Grant's zebra Moist Grassland Giraffe African elephant Gerenuk Black rhino Dik-dik East African eland Dry Thorn Scrub Blue duiker Greater kudu Bushbuck Riverine Forest Human effects on Grasslands Conversion of savanna and temperate grassland to cropland Release of CO2 to atmosphere from burning and conversion of grassland to cropland Overgrazing of tropical and temperate grasslands by livestock Damage to fragile arctic tundra by oil production, air and water pollution, and vehicles Tundra 1. Climate • • • Precipitation < 15 cm / yr – mostly snow & summer rain Arid Bitter cold -57 – 50 °C - permafrost low insolation gives short growing season 2. Distribution • • 60 – 75 °N latitude – northern North America, Asia, Greenland About 20% of the earth’s surface 3. Structure • • Simple – low spongy mat of vegetation, lichens, mosses Even trees are less than knee high 4. Relative Productivity • Low – limited by temperature and insolation Tundra Distribution Tundra • Treeless spongy mat of low growing plants • Common breeding area b/c predators visible • Organisms migratory • Cold & Windy & Dark • Ice & snow cover • Low precipitation but poor drainage b/c Permafrost Polar grassland (arctic tundra) (Fort Yukon, Alaska) Long-tailed jaeger Grizzly bear Producer to primary consumer Caribou Primary to secondary consumer Mosquito Snowy owl Arctic fox Horned lark All consumers and producers to decomposers Willow ptarmigan Dwarf Dwarfwillow willow Lemming Mountain Mountaincranberry cranberry Moss campion campion Moss Secondary to higher-level consumer Forest Types • Undisturbed areas with moderate to high rainfall • Dominated by various species of trees and other vegetation • 3 main types of forest – Tropical, Temperate, Boreal World Distribution of Forests Temperate coniferous forests Temperate deciduous forests Tropical rain forests Tropical Rainforest 1. Climate • • • 2. Precipitation over 150 cm / yr – Wet – still rainy and dry seasons Warm humid year round climate 80 °F high insolation gives long growing season Distribution • • • 3. 23.5 °N to 23.5 °S latitude – Tropic of Capricorn to Cancer About 2% of the earth’s surface Three chunks – S. & C. America, C. Africa, SE Asia Structure • • 4. Complex – stratified layers High diversity - 50-80% of terrestrial species Relative Productivity • Highest in terrestrial system – unlimited by temperature and insolation • Tropical Rainforest • Broadleaved evergreen trees • High biological diversity, Specialized niches, • Much of animal life found in canopy layer • Stratification of life in different tree layers increases niche partitioning • Paradox high diversity but very poor soils • Rapid recycling of nutrients • Little nutrients stay in soil most taken back into plants • Dense forest limits wind animal pollinators Tropical Rainforest Tropical rain forest (Manaus, Brazil) 45 Harpy eagle 40 35 Height (meters) Emergent layer Toco toucan Canopy 30 25 20 Understory Wooly opossum 15 10 Brazilian tapir 5 Black-crowned antpitta 0 Shrub layer Ground layer Harpy eagle Blue and gold macaw Ocelot Producer to primary consumer Primary to secondary consumer Squirrel monkeys Climbing monstera palm Secondary to higher-level consumer Katydid Slaty-tailed trogon Green tree snake Tree frog Ants Bromeliad Fungi Bacteria All producers and consumers to decomposers Diverse forests cleared Replaced with monospecific stands – tree plantations Songbird species often spend time in these areas Top predators hunted out and displaced Fragmentation of habitats Forests Temperate deciduous forest (Nashville, Tennessee) • Temperate Forests • Significant seasonal changes • Abundant precipitation throughout year • Dominated by a few broadleaved deciduous trees • Simple structure • Thick layer of leaf litter • Once diverse, now predators gone Broad-winged hawk Producer to primary consumer Hairy woodpecker Primary to secondary consumer Gray squirrel White oak White-footed mouse White-tailed deer Metallic Metallic woodboring beetle wood-boring and larvae beetle and Mountain winterberry Shagbark hickory May beetle Fungi Bacteria Long-tailed weasel Racer Wood frog Secondary to higher-level consumer All producers and consumers to decomposers Forests • Boreal Forests (Tiaga) • Just below tundra • Dominated by coniferous tree species – Withstand cold, rapid growth in summer • Low temperature – Low decomposition, high soil acidity • In summer soil is waterlogged = muskegs Polar evergreen coniferous forest (boreal forest, taiga) (Moscow, Russia) Blue jay Great horned owl Marten Balsam fir Moose White spruce Producer to primary consumer Primary to secondary consumer Secondary to higher-level consumer Wolf Bebb willow Pine sawyer beetle and larvae Snowshoe hare Fungi Starflower Bacteria Bunchberry All producers and consumers to decomposers Human Effects on Forests Clearing and degradation of tropical forests for agriculture, livestock grazing, and timber harvesting Clearing of temperate deciduous forests in Europe, Asia, and North America for timber, agriculture, and urban development Clearing of evergreen coniferous forests in North America, Finland, Sweden, Canada, Siberia, and Russia Conversion of diverse forests to less biodiverse tree plantations Climatograms Review
