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Joy of Science
Experience the evolution of
the Universe, Earth and Life
•  Main Contents
•  Bonus Quiz
Unless otherwise noted, all pictures are taken from wikipedia.org
Science of Environment
Are human activities affecting the global
environment?
Today’s Keywords
ecology, ecosystem, environment,
ecological niche, trophic level,
air pollution, ozone, acid rain, greenhouse effect
Contents
n  Ecology and Ecosystems
n  Threats to the Global Ecosystem and Environment
n  Debates about Global Climate Change
1. Ecology and Ecosystems
n  Ecology:
The branch of science that studies interdependent groups of living
things, called ecosystems
n  Ecosystem:
A functional unit consisting of living things in a given area, non-living
chemical and physical factors of their environment, linked together
through nutrient cycle and energy flow
Ecosystems
n  An interdependent community of all the organisms in a particular
ecosystem consists of producers, consumers, and decomposers
- Producers: Plants and other photosynthetic organisms. They obtain
atoms and energy from their physical surroundings
and convert them into carbon-based molecules
- Consumers: Animals. They obtain materials and energy from
produces or/and other organisms
- Decomposers: Bacteria and fungi. They renew the raw materials of life
Ecosystems
n  An interdependent community of all the organisms in a particular
ecosystem consists of producers, consumers, and decomposers
- Producers: Plants and other photosynthetic organisms. They obtain
atoms and energy from their physical surroundings
and convert them into carbon-based molecules
- Consumers: Animals. They obtain materials and energy from
produces or/and other organisms
- Decomposers: Bacteria and fungi. They renew the raw materials of life
n  Types of ecosystems:
1. Natural: Terrestrial ecosystem – Tundra, taiga, temperate
deciduous forest, grassland
Aquatic ecosystem – Marine ecosystem and freshwater
ecosystem
2. Artificial: Created by humans
Characteristics of ecosystem
1. Every ecosystem consists of both living and nonliving parts
2. Energy flows through ecosystem
3. Matter is recycled by ecosystems
4. Every organism occupies an ecological niche
5. Stable ecosystems achieve a balance among their populations
6. Ecosystems are not permanent, but change over time
Characteristics of ecosystem
1. Every ecosystem consists of both living and nonliving parts
Nonliving or abiotic parts form the chemical and physical
environment of ecosystem
Living organisms form the biotic part of an ecosystem:
an ecological community
Characteristics of ecosystem
2. Energy flows through ecosystem
Each species in a food web (who feeds on whom) provides energy
and chemicals for other organisms.
Energy flows from one trophic level to the next trophic level.
Only 10% of energy from one trophic level is transferred to the next
Characteristics of ecosystem
2. Energy flows through ecosystem
Each species in a food web (who feeds on whom) provides energy
and chemicals for other organisms.
Energy flows from one trophic level to the next trophic level.
Only 10% of energy from one trophic level is transferred to the next
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Characteristics of ecosystem
3. Matter is recycled by ecosystems
Atoms continuously cycle from one part of Earth to another.
Carbon cycle can illustrate the cycling of atoms through Earth’s
biosphere
Characteristics of ecosystem
4. Every organism occupies an ecological niche:
the particular way that an
organism survives in the environment
Characteristics of ecosystem
5. Stable ecosystems achieve a balance among their populations
The overall distribution of species is usually relatively constant in an
ecosystem
Characteristics of ecosystem
6. Ecosystems are not permanent, but change over time
These sort of changes are the main goal of science of ecology
progresses 2. Threats to the Global Ecosystem
and Environment
n  Acid Rain and Urban Air Pollution
n  The Ozone Problem
n  Greenhouse Effect
Acid Rain and Urban Air Pollution
n  Burning: chemical reaction of oxidation – CO2, water vapor,
hydrocarbon combustion are always released into air
Acid Rain and Urban Air Pollution
n  Three significant sources of air pollution from burning
1. Nitrogen oxides:
Nitrogen monoxide (NO), nitrogen dioxide (NO2) or more oxygen
combinations with nitrogen when air temperature is more than
500 ° C
2. Sulfur compounds:
From petroleum- and coal-based fossil fuels. Chemical combinations
of sulfur and oxygen, particularly sulfur dioxide (SO2)
3. Hydrocarbons:
Long-chain molecules of hydrocarbons are not perfectly burned so
that pieces of hydrocarbons enter the atmosphere
Acid Rain and Urban Air Pollution (cont’d)
n  The effects of air pollution and acid rain
- “bad ozone”: At ground level ozone (made of 3 oxygen which is
produced by sunlight hitting nitrogen and hydrocarbon compounds)
are caustic and harmful
- Brownish smog in major cities
Acid rain: Rain droplets with nitrogen oxides and sulfur compounds.
Long-term problem
n  Dealing with acid rain
- Political and economic effort are needed
- What can we do? The Ozone Problem
n  Ozone:
Play a beneficial role in absorbing ultraviolet radiation high in the
atmosphere
n  The Ozone Layer:
Ozone concentrated region in the atmosphere at some 30km high
Ozone detection: by collecting samples using specialized aircrafts or
by measuring characteristic spectral lines given off from satellites,
aircrafts, or by ground-based observers
The Ozone Problem
n  The Ozone Hole:
The region where ozone gas has declined significantly, found in
Antarctica first in 1985.
Cause of the ozone hole: chlorofluorocarbons (CFCs)
– main materials for aerosol spray, coolant for refrigerators and
air conditioners
(ozone + chlorine + sunlight) à (ordinary oxygen + chlorine)
n  Dealing with the threat to the Ozone Layer: An international treaty
has been made in 90’s and the use of Freon for automobile AC has
been completely forbidden since 1996
2006
Greenhouse Effect
n  Greenhouse effect: Natural temperature increase at Earth’s
surface, associated with atmospheric trapping of heat (infrared
radiation from the Sun)
n  Three points of general agreement in debates about global
warming
1. Carbon dioxide absorbs infrared radiation and acts as a
greenhouse gas
2. The burning of fossil fuels by human beings has increased the
amount of carbon dioxide in Earth’s atmosphere
3. The average global temperature has increased significantly
during the past several decades
3. Debates about Global Climate
Change
n  The main issue in global warming debates is whether
increased CO2 is entirely responsible for the observed
increase in global temperature
è International agreement on the reduction of CO2 emission,
called Kyoto Protocol
3. Debates about Global Climate
Change
n  Uncertainties for the answer to the question come from our way
of prediction about the behavior of Earth’s atmosphere, which is
through Global Circulation Models (GCMs)
Clouds: Can produce an automatic feedback counteracting
some of CO2 effects
Oceans: A constant interplay takes place between water and
atmosphere at an ocean’s surface, and CO2 moves
into and out of the oceans all the time
Sun’s energy output: Even small change of solar energy affect
the environment of Earth severely
Ex) “Little Ice Age” from 1645 to 1715
3. Debates about Global Climate
Change
n  Global warming is real!
Average global temperature is guessed as about 4 ° C up over
the next century
Average sea level change is guessed as about 60 cm level up
à Earth’s biosphere and ecosystems might be depending on the
magnitude and rate of warming. Unknown ecological disasters
may appear
3. Debates about Global Climate
Change
n  Are you willing to change your lifestyle now because it is
likely that global warming will affect the lifestyles of your
grandchildren?
Bonus Quiz 1 n  A biological system including all the organisms in a given area,
together with their surroundings is referred as a(n)
1. ecology
2. ecological community
3. ecosystem
4. ecological niche
5. trophic level Bonus Quiz 1 n  A biological system including all the organisms in a given area,
together with their surroundings is referred as a(n)
1. ecology
2. ecological community
3. ecosystem
4. ecological niche
5. trophic level Quiz 2 n  All of the organisms in an ecosystem form a(n)
1. ecology
2. ecological community
3. food chain
4. trophic level
5. ecological niche Quiz 2 n  All of the organisms in an ecosystem form a(n)
1. ecology
2. ecological community
3. food chain
4. trophic level
5. ecological niche Quiz 3 n  The composition of an ecosystem is influenced by
1. water availability
2. soil characteristics
3. average temperature
4. animal species present
5. all of the above
Quiz 3 n  The composition of an ecosystem is influenced by
1. water availability
2. soil characteristics
3. average temperature
4. animal species present
5. all of the above
Quiz 4 n  The particular way that an organism survives in the environment
is called its
1. environment
2. ecological community
3. food chain
4. trophic level
5. ecological niche Quiz 4 n  The particular way that an organism survives in the environment
is called its
1. environment
2. ecological community
3. food chain
4. trophic level
5. ecological niche Quiz 5 n  Nitrogen oxides, sulfur compounds, and hydrocarbons combine
in the atmosphere to produce
1. chlorofluorocarbons
2. air pollution
3. a special trophic level
4. a specialized ecosystem
5. none of the above Quiz 5 n  Nitrogen oxides, sulfur compounds, and hydrocarbons combine
in the atmosphere to produce
1. chlorofluorocarbons
2. air pollution
3. a special trophic level
4. a specialized ecosystem
5. none of the above Quiz 6 n  Ozone in the upper atmosphere is important because
1. it reduces the temperature of the Earth’s surface
2. it increases the temperature of the Earth’s surface
3. it absorbs ultraviolet radiation from the Sun
4. it prevents the formation of smog
5. it absorbs chlorofluorocarbons Quiz 6 n  Ozone in the upper atmosphere is important because
1. it reduces the temperature of the Earth’s surface
2. it increases the temperature of the Earth’s surface
3. it absorbs ultraviolet radiation from the Sun
4. it prevents the formation of smog
5. it absorbs chlorofluorocarbons Quiz 7 n  The buildup of carbon dioxide in the atmosphere appears to be
contributing to
1. acid rain
2. a decrease in global temperature
3. the ozone hole
4. the greenhouse effect
5. none of the above Quiz 7 n  The buildup of carbon dioxide in the atmosphere appears to be
contributing to
1. acid rain
2. a decrease in global temperature
3. the ozone hole
4. the greenhouse effect
5. none of the above