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Ch 3 Ecosystems: What They Are and How Do They Work?. Case Study . Have You Thanked The Insects Today? (Summarize). The Nature of Ecology. Ecology: the study of how organisms interact with one another and their environment. Organism: Species: Population: Community: Ecosystem: Biosphere:.
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Case Study • Have You Thanked The Insects Today? (Summarize)
The Nature of Ecology • Ecology: the study of how organisms interact with one another and their environment. • Organism: • Species: • Population: • Community: • Ecosystem: • Biosphere:
The Earth’s Life-Support Systems • Four Spheres (that make up the biosphere) • Atmosphere: • Troposphere: • Contains majority of planet’s air (nitrogen, oxygen) • Stratosphere: • Contains the ozone layer • Hydrosphere: • Lithosphere:
The Earth’s Life-Support Systems • Solar energy, the cycling of matter, and gravity sustain the earth’s life. • Solar energy warms the planet, runs the water cycle (80%), generates winds (1%) and supports plant growth through photosynthesis (0.1%). • Natural Greenhouse effect:
Ecosystem Components • Biomes: • Ex: Forests, deserts, grasslands • Aquatic Life Zones: • Ex: Lakes, Oceans, Rivers • Biotic: • Ex: producers (plants), consumers (animals) • Abiotic: • Ex: wind, temperature, water, air
Ecosystem Components • Availability of matter and energy resources can limit the number of organisms in a population. • Limiting factor (principle): • Ex: precipitation can be a limiting factor.
Ecosystem Components • Producers (autotrophs): • Photosynthesis: • (Write equation): • Consumers (heterotrophs): • Primary consumers( herbivores): • Secondary consumers (carnivores): • Third and higher level consumers: • Omnivores: • Decomposers:
Biodiversity • Biodiversity: • Human activities are destroying and degrading the habitats for many wild species and driving some of them to premature extinction. • HIPPO: • H- • I- • P- • P- • O-
Energy Flow In Ecosystems • Food chains: • Trophic levels: • Food webs: • Ecological Efficiency: • 10% rule: typically 10% energy moves from one trophic level to the next (losing 90% at each level to survival).
Soil: Renewable Resource • Soil: • Soil formation starts when bedrock is broken down into small pieces by weathering. Lichen add nutrients. Over hundreds of years inorganic and organic matter builds up on the bedrock . • Renewed very slow. Can take 15 yrs to form 1 cm of soil. • Humans have accelerated soil erosion causing it to become a nonrenewable resource.
Matter Cycling in Ecosystems • Nutrients: • Biogeochemical cycles (nutrient cycles): • Hydrologic cycle (water cycle): • Powered by the sun • Only 0.024% of all the water on earth is available freshwater.
Human Effects on Water Cycle • 4 ways • We use it quicker then it can replenish itself. • We clear vegetation to build infrastructure which decreases infiltration that recharges groundwater. Can also cause flooding and accelerate erosion. • We add nutrients (phosphate and nitrate) to water which can cause algae blooms. • Water cycle is speeding up due to man made climate change.
Carbon Cycle • Carbon Cycle: • Human effects • Clearing of trees and other plants that absorb CO2 • We add CO2 to the atmosphere by burning fossil fuels and wood.
Nitrogen cycle • Nitrogen Cycle: • Human effects • We add NO to atmosphere which can cause acid rain. • We add N2O through livestock and fertilizer which can cause ozone depletion. • NO3 can leach into groundwater • Release NO stored in trees when we clear forests. • Remove N from top soil when we irrigate crops.