4/21/2013. Ecology. Ecology and the biosphere. Environments vary across the planet. Predictable air circulation patterns. Incidence of sunlight varies

Transcription

1 Ecology The study of the interactions of organisms with each other and with the environment Ecologists work at all levels of biology from molecules to biosphere Ecology and the biosphere Chapter 52 Environments vary across the planet Macroclimate differences due to differences in amount of sunlight and atmospheric circulation pattern Microclimate differences due to tilt of earth, bodies of water and topography Incidence of sunlight varies Predictable air circulation patterns 1

2 Tilt of earth causes seasonality Currents distribute energy and water Rainshadow effect Climates are changing 2

3 Mean Annual Temperature, in C Temperature and precipitation determine biome distribution Biomes are large-scale ecosystems defined by their dominant vegetation More C 3 plants (e.g., trees) with more precipitation, more C 4 plants (e.g., grasses) with less precipitation Tundra 1 Desert Taiga 2 Boreal forest 3 Grassland 10 Temperate Forest 5 Temperate Rain 6 Forest Savanna Tropical Seasonal Forest Tropical Rain Forest DESERT Minimal precipitation Temperatures vary widely daily and seasonally Adaptations for water conservation and resistance to heat Animals tend to be nocturnal and nomadic Plants have thick skins, spines, whitish in color Overgrazing a threat Sensitive to disturbance Mean Annual Precipiation, in mm HOT AND COLD DESERTS 3

4 TEMPERATE GRASSLANDS More temperature difference between winter and summer Lower precipitation supports grasses, but not trees Also called steppe or prairie Once widespread, but has been converted to agriculture Overgrazing occurs Fires and grazing important SAVANNA Grassland interspersed with trees Precipitation occurs during the rainy season 4

5 TUNDRA Minimal rain Permafrost keeps moisture unavailable Alpine tundra is found on mountaintops Very short growing season, with cold harsh winters Most animals migrate south or downhill in winter Low biological productivity and low diversity Treeless Threatened by oil/gas drilling and climate change ALPINE AND ARTIC TUNDRA Figure 52.12h BOREAL FOREST Evergreen tree species Cool and dry climate Nutrient poor, acidic soil Taiga describes northernmost part of boreal forest that has fewer trees Denali National Park, Alaska, in autumn 5

6 TEMPERATE RAINFOREST Heavy rainfall and mild temperatures Coniferous trees Erosion and landslides affect the fertile soil Most old-growth is gone as a result of logging TEMPERATE DECIDUOUS FOREST Deciduous trees lose their broad leaves each fall Fertile soils Rich variation of tree species Logging impacts TEMPERATE RAIN FOREST TROPICAL RAINFOREST Year-round rain and warm temperatures Dark and damp Lush vegetation Diverse species Very poor, acidic soils as nutrients are in living organisms Logging and agriculture threaten ecosystems 6

7 TROPICAL DRY FOREST Also called tropical deciduous forest or tropical seasonal forest Wet and dry seasons Warm temperatures Much of it converted to other uses CHAPARRAL OR MEDITERRANEAN A regional biome Densely thicketed, evergreen shrubs Mild, wet winters and warm, dry summers Fire important 7

8 Aquatic biomes Defined by physical conditions Freshwater and salt Zones vary in conditions 8

9 Many factors both abiotic and biotic control the distribution of organisms 9

10 WHICH BIOME DOES NOT HAVE ENOUGH PRECIPITATION TO SUPPORT TREES, IS ALSO CALLED STEPPE OR PRAIRIE, AND HAS BEEN CONVERTED TO AGRICULTURE? 20% 20% 20% 20% 20% WHICH BIOME IS FOUND IN THE COASTAL PACIFIC NW OF THE U.S., HAS HEAVY RAINFALL; CEDAR, SPRUCE, AND HEMLOCK TREES; AND MOISTURE-LOVING 20% 20% 20% 20% 20% ANIMALS? a) Tropical rainforest b) Temperate grassland c) Chaparral d) Taiga e) Tundra 1. Tropical rainforest 2. Temperate grasslands 3. Temperate rainforest 4. Taiga 5. Tundra a) b) c) d) e) One reason that deserts tend to be found at 20ºN and S latitude is that A. deserts are dry. B. it s warmer near the equator. C. global wind and pressure patterns affect where rain falls. D. desert soils are different from tropical rain forest soils. E. mountains change rainfall patterns. deserts are dry. it s warmer near the equ... 20% 20% 20% 20% 20% desert soils are different... global wind and pressure... mountains change rainfal... 10