Presentation on theme: "Chapter 19 Great Idea: Ecosystems are interdependent communities of living things that recycle matter while energy flows through."— Presentation transcript:
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 ecosystems Matter is recycled by ecosystems Every organism occupies an ecological niche Stable ecosystems achieve a balance among their populations Ecosystems are not permanent, but change over time
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 Waste Nothing is ever thrown away 2000 vs 1986: increases of plastics and paper Example: plastic bags Landfills Decay is very slow (newspaper readable after 50 years) Response Recycling Large depositories in rural area
The Ozone Problem Ozone O 3 Absorbs ultraviolet radiation The Ozone Layer Stratosphere Highest concentration
The Ozone Problem cont. The Ozone Hole Concentration of ozone reduced Yearly occurrence over Antarctica noticed in 1985 Linked to chlorofluorocarbons (CFCs) introduced in 1950s and used in aerosol spray and refrigerators / air- conditioners. 2O 3 + Cl +sunlight = 3O 2 +Cl Dealing with the Threat to the Ozone Layer Reduction of CFCs Treaty of international congress meeting in Montreal in 1986
Acid Rain and Urban Air Pollution Burning introduces chemicals Nitrogen oxides Sulfur compounds Hydrocarbons Effects Air pollution Production of bad ozone Acid rain Reduction Reduce emissions Power plants Vehicles
The Greenhouse Effect Greenhouse Effect CO 2 absorbs heat but not light Traps heat on earth Global Warming Climate change Main points CO 2 is a greenhouse gas Burning fossil fuels increases CO 2 Average global temperature has significantly increased 1990s warmest decade
Photographers 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 increasingRhone 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 CO 2 in atmosphere
Debates About Global Climate Change Is the temperature increase short-term or long term? Is the increased CO 2 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