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Introduction to Environmental Studies. Ecology the study of how plants, animals, and microbes interact with each other and with their physical environment Environmental Science the study of how humans impact natural ecosystems. - PowerPoint PPT Presentation
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Introduction to Environmental Studies
• Ecology
the study of how plants, animals, and microbes interact with each other and with their physical environment
• Environmental Science
the study of how humans impact natural ecosystems
The First Principle of Ecology: everything is connected to
everything else
What are the implications of this principle?
History of Environmentalism
• Thoreau and Emerson
• John Muir
• Gifford Pinchot
• Theodore Roosevelt
• Rachel Carson
• 1960’s
• Earth Day
Most famous for his book, Walden, which details simple
living in Nature
• A. Ralph Waldo Emerson
• B. John Muir
• C. Aldo Leopold
• D. Henry David Thoreau
• E. Gifford Pinchot
In the late 1800’s, he started the Sierra Club, an
environmental organization still going strong today
• A. Ralph Waldo Emerson
• B. John Muir
• C. Aldo Leopold
• D. Henry David Thoreau
• E. Gifford Pinchot
In the book Silent Spring, this author and scientists warned of
the dangers of pesticides• A. Aldo Leopold
• B. Gifford Pinchot
• C. Thoreau
• D. Rachel Carson
• E. Robert Underwood Johnson
Creator of the U.S. Forest Service
• A. Theodore Roosevelt
• B. Franklin Roosevelt
• C. Aldo Leopold
• D. Ronald Reagan
• E. Henry David Thoreau
Changing Worldviews
• Expansionist Worldviewnatural resources are unlimited and for our use
• Ecological Worldviews– Conservationwise use and management of natural resources
today will insure use for future generations– Preservationminimal use of nature – nature should not be
thought of as just here to serve humans – nature deserves to exist for its own sake
Deep Ecology
Sustainable development – a pattern of resource use that aims to meet human needs while preserving the environment so that these needs will always be met in the future
Principles of Ecology
To understand environmental issues and foster sustainable development,
humans should take lessons form how ecosystems function …
Ecosystem – a group of plants, animals, and microbes interacting with each other and the physical environment in a sustainable way
ecosystem size …
• very small … a small pond … your back yard
or very large …
biomes – large terrestrial ecosystems
biosphere – the earth’s “super-ecosystem” … includes all life
forms and the physical environments supporting life
ecotone – transitional region between adjacent ecosystems
Categories of Organisms
(common to every ecosystem)
autotrophs – (producers) “self-feeding” – typically, green plants
heterotrophs – consumers and detritivores and decomposers
types of consumers …
herbivores (primary consumers)
carnivores (secondary or tertiary consumers)
omnivores (primary, secondary or tertiary, depending on the meal)
decomposers (bacteria and fungi)
break down organic material recycling nutrients in the process
detritivores and scavengers –exploit the available energy in recently dead organisms
Feeding Relationships
food chainsshow the direction of energy flow
between organisms in an ecosystem
food weba more comprehensive model showing all feeding pathways
trophic levels – steps on a food chain
biomass – total mass of biological material (living) – usually refers to specific trophic level
Fig. 3-18, p. 49
Secondaryconsumers
(perch)
10
100
1,000
10,000Usable energy
available ateach tropic level(in kilocalories)
Heat
Heat
Heat
Heat
Heat
Producers(phytoplankton)
Tertiaryconsumers
(human)
Primaryconsumers
(zooplankton)
Pyramid of Energy Flow
Decomposers
biomass pyramid – shows the relative proportions of biomass at each trophic level
• in the most efficient ecosystems, there is only about 10% of food energy available for the next higher trophic level – what happened to the other 90%?
• food chains in most terrestrial ecosystems rarely go higher than four trophic levels
Fig. 9-16, p. 197
DDT in fish-eatingbirds (ospreys)
25 ppm
DDT in largefish (needle fish)2 ppm
DDT in smallfish (minnows)0.5 ppm
DDT in water0.000003 ppm,or 3 ppt
DDT inzooplankton0.04 ppm
Biomagnification of DDT
Toxins in Food Chains
• bioaccumulation: the storing of toxins in an organism over time
• biomagnification: an increase in the concentration of toxins as you move higher in a food chain
Non-feeding Ecological Relationships
symbiosis – a close physical relationship between two different
species
commensalism – one organism benefits while the other is
unaffected
mutualism – beneficial to both organisms
competition
• intraspecific – competition between members of the same species – a major force in Natural Selection
• interspecific – competition for limited resources between different species
Abiotic factors – physical and chemical environmentalconditions that determine the types of plants and animals in an ecosystem … examples?
optimum conditions – for every abiotic factorthere exists a certain level at which a speciesdoes best
limiting factor – an environmental factor thatrestricts the success of a species
range of tolerance – acceptable range of environmental conditions for each species
Lower limitof tolerance
Upper limitof tolerance
TemperatureLow High
Abundance of organismsFew
organismsFew
organismsNo
organismsNo
organisms
Zone ofintoleranceZone of
physiological stress
Zone ofintolerance Zone of
physiological stress
Optimum range
Po
pu
lati
on
Siz
e
Fig. 3-11, p. 43
Range of Tolerance
habitat and niche – the place where organism is found and the role it plays
Ecosystem Sustainability
Energy – life depends on producer’s ability to convert solar energy to chemical energy in the form of organic molecules that consumers can utilize
cellular respiration – the breakdown of glucose to release energy for cell activity
energy flows “one way” through an ecosystem,it can not be recycled
Solarenergy
Chemical energy(photosynthesis)
Chemicalenergy(food)
Mechanicalenergy
(moving,thinking,
living)
Wasteheat
Wasteheat
Wasteheat
Wasteheat
Fig. 2-11, p. 32
Second Law of Thermodynamics
continuity of life depends upon an unending supply of nutrients
CHONPS – the “elements of life”
Nutrient Cycling
carbon cycle
nitrogen cycle
Ecological Succession
Succession- a series of regular predictable changes occurring to an ecosystem after a disturbance
climax community- the end result of succession
characteristics- stable, sustainable
primary succession- begins with soil formation, occurs after major disturbance
secondary succession- more common, faster
Seven Major Terrestrial Biomes
Fig. 5-8, p. 84
Precipitation and Temperature Affects Biome Type
Polar
Subpolar
TropicalChaparral
Grassland
Desert
Desert
Scrubland
SavannaDry
Cold
Tundra
Coniferous forest
Decreasing
Temperate
precipitation
Dec
reas
ing
Deciduousforest
Tropicalseasonal
forest
Wet
Ho
t
Rain forest
tem
pera
ture
• climatographs – a graph showing average precipitation and temperature for a given region
• net primary productivity – the amount of energy available for consumers resulting from photosynthesis
how is NPP related to temperature and precipitation?
Fig. 3-20, p. 50
Swamps and marshes
Tropical rain forest
Temperate forest
Northern coniferous forest
(taiga)
Savanna
Agricultural land
Woodland and shrubland
Temperate grassland
Tundra (arctic and alpine)
Desert scrub
Extreme desert
Aquatic EcosystemsEstuaries
Lakes and streams
Continental shelf
Open ocean
Terrestrial Ecosystems
800 1,600 2,400 3,200 4,000 4,800 5,600 6,400 7,200 8,000 8,800 9,600
Average net primary productivity (kcal/m2/yr)
Net Primary Productivity in Major Life Zones and Ecosystems