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:

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- 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.