Ecosystems: How do they work?

ECOSYSTEMS: How do they work Living in the Environment 14 th Edition Chapter 4 Shohail Choudhury 4

ECOLOGY Ecology is the study of connections in the natural world (Figure). An Ecosystem is a community of different species interacting with each other and with their nonliving environment for matter and energy. About 1.4 million of species identified. Estimate: 3.6 to 100 million. Any form of life=Organism.

Earth’s Life Support System Troposphere: Sea level -11 miles Stratosphere: 11-30 miles. Filters. Lithosphere: Fuels and minerals. Atmosphere Vegetation and animals Soil Rock Biosphere Crust core Mantle Lithosphere Crust Lithosphere (crust, top of upper mantle) Hydrosphere (water) Atmosphere (air) Biosphere (Living and dead organisms) Crust (soil and rock)

The Source of Energy Solar energy makes the earth warm to support life. Solar radiation Energy in = Energy out Reflected by atmosphere (34%) UV radiation Absorbed by ozone Absorbed by the earth Visible light Lower Stratosphere (ozone layer) Troposphere Heat Greenhouse effect Radiated by atmosphere as heat (66%) Earth Heat radiated by the earth

Sustaining life of earth
One way of energy flow
Cycling of matters

Ecosystem Components Biomes: Terrestrial parts of the biosphere. Desert, Grassland. Role of climate Aquatic life zones 15,000 ft 10,000 ft 5,000 ft Coastal mountain ranges Sierra Nevada Mountain Great American Desert Rocky Mountains Great Plains Mississippi River Valley Appalachian Mountains Coastal chaparral and scrub Desert Coniferous forest Coniferous forest Prairie grassland Deciduous forest Average annual precipitaion 100-125 cm (40-50 in.) 75-100 cm (30-40 in.) 50-75 cm (20-30 in.) 25-50 cm (10-20 in.) below 25 cm (0-10 in.)

Ecosystem Components Fig: Major biomes found along the 39 th parallel across the USA. The difference reflects changes in climate (precipitation and temperature). 15,000 ft 10,000 ft 5,000 ft Coastal mountain ranges Sierra Nevada Mountain Great American Desert Rocky Mountains Great Plains Mississippi River Valley Appalachian Mountains Coastal chaparral and scrub Desert Coniferous forest Coniferous forest Prairie grassland Deciduous forest Average annual precipitaion 100-125 cm (40-50 in.) 75-100 cm (30-40 in.) 50-75 cm (20-30 in.) 25-50 cm (10-20 in.) below 25 cm (0-10 in.)

Components of Ecosystem Abiotic (Nonliving): Water, air, nutrients, solar energy. Biotic (Living): Plants, animals and microbes. Law of tolerance: Physical and chemical factors. Limiting factor: Any abiotic factor. Population size Low High Temperature Zone of intolerance Zone of physiological stress Optimum range Zone of physiological stress Zone of intolerance No organisms Few organisms Lower limit of tolerance Abundance of organisms Few organisms No organisms Upper limit of tolerance

Biotic Components of Ecosystem Producers (autotrophs) Photosynthesis Consumers (heterotrophs) Aerobic respiration Decomposers Heat Heat Heat Heat Heat Abiotic chemicals (carbon dioxide, oxygen, nitrogen, minerals) Producers (plants) Decomposers (bacteria, fungus) Consumers (herbivores, Carnivores,omnivores) Solar energy

Trophic Levels Fig: How chemical energy transfers through trophic levels. (Food Chain)

Food Web Complex Network of Food Chain Less energy for high trophic level. Why few carnivores? (Tiger/Eagles) Why these are vulnerable to extinction? Humans Blue whale Sperm whale Crabeater seal Killer whale Elephant seal Leopard seal Adélie penguins Petrel Fish Squid Carnivorous plankton Krill Phytoplankton Herbivorous zooplankton Emperor penguin

Pyramid of Energy Flow
Genetic
Species
Ecological
Functional
Biological Diversity Heat Heat Heat Heat Heat 10 100 1,000 10,000 Usable energy Available at Each tropic level (in kilocalories) Producers (phytoplankton) Primary consumers (zooplankton) Secondary consumers (perch) Tertiary consumers (human) Decomposers

Global Hydrologic Cycle Matter Cycling in Ecosystems Human Activity

The Carbon Cycle (Terrestrial) photosynthesis aerobic respiration Terrestrial rocks Soil water (dissolved carbon) Land food webs producers, consumers, decomposers, detritivores Atmosphere (mainly carbon dioxide) Peat, fossil fuels combustion of wood (for clearing land; or for fuel sedimentation volcanic action death, burial, compaction over geologic time leaching runoff weathering

The Carbon Cycle (Aquatic) diffusion between atmosphere and ocean Carbon dioxide dissolved in ocean water Marine food webs producers, consumers, decomposers, detritivores Marine sediments, including formations with fossil fuels combustion of fossil fuels incorporation into sediments death, sedimentation uplifting over geologic time sedimentation photosynthesis aerobic respiration

How Do Ecologists Learn About Ecosystems?
Field research
Remote sensing
Geographic information systems (GIS)
Laboratory research
Systems analysis

GIS and Ecosystem Critical nesting site locations USDA Forrest Service Topography Habitat type Real world Private owner 1 USDA Forest Service Private owner 2 Forest Wetland Grassland Lake

Poster Competition
Chapter 6 has maps( shows you where your biomes are located Fig 6-16 pg 111) and discusses biomes.
The web - Search for pictures and more information.
Prepare your poster.
Present it (during the lunch break or other suitable time).
Worth 20 points. –15 points poster, 5 points notes on other biomes when groups are presenting.

Specimen

The Nitrogen Cycle NO 3 - IN SOIL NITROGEN FIXATION by industry for agriculture FERTILIZERS FOOD WEBS ON LAND NH 3 , NH 4 + IN SOIL 1. NITRIFICATION bacteria convert NH 4 + to nitrate (NO 2 - ) loss by leaching uptake by autotrophs excretion, death, decomposition uptake by autotrophs NITROGEN FIXATION bacteria convert to ammonia (NH 3 + ) ; this dissolves to form ammonium (NH 4 + ) loss by leaching AMMONIFICATION bacteria, fungi convert the residues to NH 3 , this dissolves to form NH 4 + 2. NITRIFICATION bacteria convert NO 2 - to nitrate (NO 3 - ) DENTRIFICATION by bacteria NITROGENOUS WASTES, REMAINS IN SOIL GASEOUS NITROGEN (N 2 ) IN ATMOSPHERE NO 2 - IN SOIL

The Phosphorus Cycle Fertilizers Detergents Cutting tropical rainforests Guano FERTILIZER ROCKS LAND FOOD WEBS DISSOLVED IN OCEAN WATER MARINE FOOD WEBS MARINE SEDIMENTS weathering agriculture uptake by autotrophs death, decomposition sedimentation settling out leaching, runoff weathering DISSOLVED IN SOILWATER, LAKES, RIVERS uptake by autotrophs death, decomposition uplifting over geologic time uplifting over geologic time mining mining excretion excretion

The Sulphur Cycle

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Ecosystems: How do they work?

by Shohail Choudhury

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