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What is ecology? the study of the interactions between organisms and their environment
Schindler et al., 1974, Canada Will adding nitrogen and phosphorus promote the growth of algae in lakes? N and P added to this lake Barrier separating the lakes
How might nitrogen and phosphorus • get into the lake naturally? 2. What would be the effect of these nutrients on life forms in the lake?
What are the components of the environment? Abiotic (temperature, light, water, minerals, air) Biotic (living things; how they interact with each other and the abiotic components)
How do you study these interactions? Organismal ecology- how do organisms cope with the abiotic limits of their environment? Population ecology-factors that affect population density and growth?
Community ecology- interactions between species: predation, competition, symbiosis Ecosystem ecology- energy flow, nutrient cycling (abiotic components are considered, too) Biosphere- from the highest mountains to the deepest oceans
Abiotic components • Sunlight • Significance of sunlight? • Factors that affect access to sunlight? • terrestrial • aquatic II. Water terrestrial aquatic organisms
III. Temperature effect on metabolism distribution of organisms “warm-blooded” and “cold-blooded” organisms IV. Wind- effect on homeostasis reproduction growth patterns
V. Rocks and soil effect on distribution, density of organisms VI. Natural disasters succession rare events (volcanic eruptions) more frequent events (fires) human-caused (oil spills)
Air circulation doldrums
As warm air rises, it cools and produces rain Cooled air sinks at 30o N and 30o S and is warmed as it sinks Wet again at 60o N and 60o S Dry at poles
Ocean currents warm cold
Ocean currents tend to moderate climate near the coast Water heats and cools more slowly than air, so climate is more stable
Local climate proximity to water mountains effect of altitude on temperature effect on air flow
Biomes- ecosystems that cover large geographical areas Terrestrial Aquatic
Features of tropical forests “Vertical stratification” Little light penetrates the canopy Many epiphytes (plants that grow on other plants) Rainfall is variable
Savanna Large herbivores and their predators Grasslands with a few scattered trees
Desert Very sparse rainfall Soil temperature can be as high as 140o during the day Plants grow very slowly Plants and animals are adapted to conserve water Plants often have spines or thorns
Temperate grassland Prairies Pampas Steppes Seasonal drought Fires Grazing Soil is deep and rich in nutrients
Temperate deciduous forests Climate is moist enough to support growth of trees Cold winters: trees drop leaves animals hibernate birds migrate Few original forests left in North America, but some have recovered
Coniferous forests Usually have very few tree species Northern coniferous forest (taiga) is the largest terrestrial biome (“spruce-moose” biome) Subject to heavy snowfall. Significance of tree shape? Significance of needles?
Tundra Permafrost, cold temperatures, high winds Very dry climate, but water stands because it cannot penetrate the permafrost Growing season is very short (2 months) Similar conditions exist at high altitudes, whatever the latitude (alpine tundra)
What is the principal biome in coastal California?
Chaparral Mild, rainy winters; long, hot dry summers “Mediterranean climate” Dense, spiny evergreen shrubs Plants are adapted to and dependent on fire
Summary: what factors affect biomes? Temperature Latitude Water Ocean, wind currents What factors threaten biomes?
Rain forest • Why is the rain forest being cleared • at a rapid rate? • Is this an appropriate use for this land? • Why is the rain forest exceptionally • “productive”, compared to other biomes?
Grasslands (savanna, prairie) Why are these biomes disappearing? Deserts Why does irrigation tend to damage soils? Why are deserts particularly sensitive to this damage?
Deciduous forests what has been the effect of defores- tation on “top carnivores”? Why has deforestation benefited such species as robins, woodchucks, and deer?
Coniferous forests What is acid rain? Why are the northern forests (coniferous and deciduous) especially affected by acid rain? Tundra What would happen if the permafrost melted?
Chaparral Can too much fire prevention be bad for the biome (and the people living in it)?
Aquatic biomes freshwater marine estuaries Largest part of the biosphere
Example: lake (plants have roots) (light) (too dark for photosynthesis) Benthic zone