Chapter 19

Great Idea:Ecosystems are interdependent communities of

living things that recycle matter while energy flows through.

Ecology and Ecosystems Ecology

Branch of science focuses on natural living systems in the broadest sense

Ecosystems includes all different kinds of living

things in a given area together with the environment

Ecosystems can be small or large. The emphasize is to look at the system –its energy and matter- as a whole, rather than a group of independent parts

Community Producers –organisms that obtain

atoms and energy form physical surroundings and convert them into Carbon-based molecule of life

Consumers – such as animals Decomposers – Organisms, such as

bacteria and fungi, that renew the raw materials of life in a ecosystem

Characteristics of Ecosystems

Every Ecosystem consists of both living and nonliving parts

Energy flows through ecosystemsMatter is recycled by ecosystemsEvery organism occupies an ecological nicheStable ecosystems achieve a balance among their

populationsEcosystems are not permanent, but change over

time

The Carbon Circle

The Law of Unintended Consequences It is virtually impossible to change one aspect of a complex

system without affecting other parts of the systems, often in as-yet unpredictable ways.

Examples:Extracting petroleum and water from underground

causes land subsidence;Lake Victoria: largest fresh water lake in Africa

Nile perch – small fishes – algae and parasite bearing snails – hazard to lake and human

Roast Nile perch – wood – extensive soil erosion and other unintended changes

A single new species has drastically altered a vast ecosystem.

The Problem of Urban Landfills

Solid WasteNothing is ever thrown away2000 vs 1986: increases of plastics and paperExample: plastic bags

LandfillsDecay is very slow (newspaper readable after 50 years)

Response RecyclingLarge depositories in rural area

The Ozone Problem

Ozone O3

Absorbs ultraviolet radiationThe Ozone Layer

Stratosphere Highest concentration

The Ozone Problem cont.The Ozone Hole

Concentration of ozone reduced Yearly occurrence over

Antarctica noticed in 1985Linked to chlorofluorocarbons

(CFCs) introduced in 1950s and used in aerosol spray and refrigerators / air-conditioners.

2O3 + Cl +sunlight = 3O2+Cl

Dealing with the Threat to the Ozone LayerReduction of CFCs

Treaty of international congress meeting in Montreal in 1986

Acid Rain and Urban Air PollutionBurning introduces

chemicalsNitrogen oxidesSulfur compoundsHydrocarbons

EffectsAir pollution

Production of bad ozoneAcid rain

ReductionReduce emissions

Power plants Vehicles

The Greenhouse EffectGreenhouse Effect

CO2 absorbs heat but not lightTraps heat on earth

Global WarmingClimate change

Main pointsCO2 is a greenhouse gasBurning fossil fuels increases

CO2

Average global temperature has significantly increased 1990s warmest decade

Photographer’s Perspectives on Global warming (by Gary Braasch)

Global Warming (by Gary Braasch)

Upsala Glacier in Argentina: 200 m disappear annually

Water level of Tavalu Island in Pacific Ocean keeps on increasing Rhone Glacier in Sweden decreases 2.5 km from 1859 to 2001

Mount Hood in Oregan, same time 1985 and 2002

Global warming （ continue）

Penguins in Adelie decrease 33% in the last 25 years。

Sea lives in Monterey Bay in CA move toward north

Dry bottom of the lake in Florida

More than 100 days of high temperature in ichuan, China, the hottest in more than 100 years.

Global Warming and increasing of CO2 in atmosphere

Debates About Global Climate Change Is the temperature increase short-term or long term? Is the increased CO2 levels really responsible for temperature

increase?Dealing with the Green House Effects

Renewable Energy: Solar and Wind, etc

Solar Water Heater

Solar Electric System

Wind Turbines for Electricity