Transcript Keystone Environmental Science Lecturex

Environmental Science
Overview
This guide has been designed to
help cover the eligible content for
the KEYSTONE EXAM
Table of Contents
I.
What is Environmental Science?
• What are the major issues?
II. Ecosphere Organization
• Biomes / Aquatic Life Zones
• Biotic / Abiotic Components
III. Biodiversity
• Definition
• Factors that impact biodiversity
IV. Categories of Species
• Relationships and interactions
V. Water
• Availability of the resource
• Water pollution and testing procedures
VI. Pollution and Hazardous Wastes
• Categories
VII. Agriculture
• Pesticides/Pest Control
• Soil
• Forestry
VIII. Global Warming Issues
I. WHAT IS ENVIRONMENTAL
SCIENCE:
A. Interdisciplinary Science that…
1.) Help us understand how the earth
works
2.) Learn how we are affecting the
earth’s life support systems
3.) Propose and evaluate solutions to
the environmental problems we face.
B. ENVIRONMENTAL PROBLEMS
Three major categories:
1) NATURAL RESOURCE
DEPLETION
2) POLLUTION
3) EXTINCTION
1. RESOURCE DEPLETION
- DEPLETION:
- A large part of these resources has
been used.
- Natural resources:
(sunlight, air ,water, soil, plants,
minerals, animals, fossil fuels, etc)
- Two categories:
RENEWABLE and NON-RENEWABLE
RENEWABLE –
resources that can be continually replaced
NON-RENEWABLE –
resources that cannot be replaced
ENVIRONMENTALLY
SUSTAINABLE SOCIETY
Satisfies the basic needs
for…
food, water, air, and
shelter
• Resources that can be used
in the indefinite future
without being depleted
• Does not prevent future
generations from meeting
these needs
•
•
•
•
•
•
•
Air Pollution
Global climate
change
Stratospheric ozone
depletion
Urban air pollution
Acid deposition
Outdoor pollutants
Indoor pollutants
Noise
Biodiversity Depletion
• Habitat destruction
• Habitat degradation
• Extinction
Major
Environmental
Problems
•
•
•
•
•
•
•
•
Water Pollution
Sediment
Nutrient overload
Toxic chemicals
Infectious agents
Oxygen
depletion
Pesticides
Oil spills
Excess heat
Waste Production
• Solid waste
• Hazardous
waste
Food Supply Problems
• Overgrazing
• Farmland loss
and degradation
• Wetlands loss
and degradation
• Overfishing
• Coastal pollution
• Soil erosion
• Soil salinization
• Soil waterlogging
• Water shortages
• Groundwater
depletion
• Loss of biodiversity
• Poor nutrition
THE ROOT OF
ENVIRONMENTAL PROBLEMS
Almost all environmental problems can
be traced back to…
1) POPULATION CRISISNumber of people grows too quickly
for the earth to support.
2) CONSUMPTION CRISISPeople are using up, polluting, wasting
things faster than can be replaced.
Populations
Group of organisms that
belong to same species and
live in a particular place at the
same time
Key Features of Population
A. Population Size
• The number of individuals in a
population
• Size will effect the populations ability
to survive
• SMALL Populations are more prone to
extinctions and are impacted more by
random events and inbreeding
Populations Can Grow, Shrink, or
Remain Stable
Population size governed by:
Births
Deaths
Immigration
Emigration
Population change =
(births + immigration) – (deaths +
emigration)
B. Population Density
The number of individuals that live in an
area at one time
Count all the individuals in a population
estimate by sampling
C. Dispersion
The way the individuals are arranged in
space
Clumped Elephants
** MOST COMMON SPATIAL
PATTERN IN NATURE
Uniform
(creosote bush)
Random
(dandelions)
** MOST COMMON SPATIAL
PATTERN IN NATURE
Population Growth Rates
Simple population
growth models are
described as the
difference between the
birth rate and the death
rate within a population.
Models for Population Growth
Rates
A. Exponential Growth Model:
Observed in populations with few or
no resource limitations.
Starts slow and then increases
 “J-shaped curve”
Exponential Growth
Exponential Growth (J-shape Curve)
Often described in terms of…
1. Biotic Potential:
How large a population could grow to if there were
unlimited resources
Populations typically can’t grow
exponentially forever.
2. Environmental Resistance:
All of the living and non-living
factors working to hold a
population size down.
3. Carrying Capacity “K”
Number of sheep (millions)
Number of individuals of a given species that can be
sustained in a given space indefinitely
Determined by biotic potential and environmental
resistance working against each other
2.0
1.5
1.0
.5
1800
1825
1850
1875
1900
1925
What if we exceed the Carrying
Capacity?
• The population can go above “K”
for a short period of time
• The population will fail to recover
• If the recovery is too severe it will
result in a CRASH or DIEBACK
Number of reindeer
Population
overshoots
carrying
capacity
Population
Crashes
Carrying
capacity
Year
B. Logistic Growth Model
Exponential at
first…
Slowing as the
population
encounters
environmental
resistance
“K”
Population size
(N)
“S- shaped
curve”
Time (t)
Factors that Influence Populations
A. Density-Independent Population
Controls:
• Affect a population size regardless of
the density
• Flood, hurricanes, drought, fire,
habitat destruction, pesticide
spraying
B. Density-Dependent
Population Controls:
• Greater effect as density increases
• Effects of competition, predation,
parasitism and disease
Population Growth
Linear Growth
Exponential
Growth
Doubling Time/
Rule of 70
Fig. 1-2 p. 4
Fig. 1-3 p. 5
Ecological Footprint
Per Captia Ecological Footprint
(Hectares of land per person)
Country
10.9
United States
5.9
The Netherlands
India
Country
1.0
Total Ecological Footprint
(Hectares)
3 billion
hectares
United States
The Netherlands
India
94 million hectares
1 billion
hectares
Fig. 1.10, p. 11
II. Ecosystem
Organization:
Biosphere
A. Ecosystem Classification
Ecosystems
1. Organism:
• Any Living thing
2. Population:
• Group of interacting
Individuals of the same
species
Fig. 4.2, p. 72
Communities
Populations
Organisms
3. Community:
• Populations of all the different
species occupy a particular
place
4. Ecosystem:
• Community of different species
interacting with one another
5. Biosphere:
• All of the Earth’s Ecosystems
B. Biomes and Aquatic Life
Systems
1. Biomes:
Land portion of the biosphere
Distinct climate and specific lifeforms adapted for life within that
climate.
Climate - long-term patterns of
weather is the primary factor
determining the type of life
2. Aquatic life zones:
Marine and Freshwater
Ecosystem Concepts and
Components
Coastal chaparral
and scrub
Coastal
mountain
ranges
Sierra
Nevada
Mountain
Desert
Coniferous
forest
Great
American
Desert
Coniferous
forest
Rocky
Mountains
15,000 ft
10,000 ft
5,000 ft
Prairie
grassland
Great
Plains
Deciduous
forest
Mississippi
River Valley
Appalachian
Mountains
Average annual precipitaion
100-125 cm (40-50 in.)
75-100 cm (30-40 in.)
50-75 cm (20-30 in.)
Fig. 4.9, p. 76
25-50 cm (10-20 in.)
below 25 cm (0-10 in.)
III. COMPONENTS OF AN ECOSYSTEM
1. ABIOTIC –
• Non-living components
(Water, air, nutrients and solar
energy)
2. BIOTIC –
• Living components
(Plants, animals,
microorganisms)
A. Abiotic Ecological Factors
-Each population within an
ecosystem has a RANGE OF
TOLERANCE to abiotic
factors
– Acceptable levels required for
survival
Lower limit
of tolerance
Few
organisms
Abundance of organisms
Few
organisms
No
organisms
Population size
No
organisms
Upper limit
of tolerance
Zone of
Zone of
intolerance physiological stress
Low
Optimum range
Temperature
Zone of
Zone of
physiological stress intolerance
High
B. Range of Tolerance:
• Minimum and maximum Range in
which physical and chemical
variations can be tolerated
• Individuals in a population may
have different levels of tolerance
–Due to genetics, health and age
–Most susceptible during juvenile
and reproductive stages
C. Limiting Factor
The one factor that is most
important in regulating
population size
Limiting Factor Principle:
Too much or too little of any
abiotic factor can limit a
population
D. ABIOTIC LIMITING FACTORS
•
•
•
•
•
•
•
Sunlight
Temperature
Precipitation
Wind
Altitude
Fire frequency
Soil
• Water currents
• Dissolved nutrient
concentration
(O,N,P)
• Salinity
• Suspended solids
-NICHE:
E. Biotic Interactions:
Niches and Adaptation
-The “role” that an organism plays in an
ecosystem
-HABITAT
the actual physical location where a
species lives.
-Two main types of Niches…
A. Generalist
B. Specialist
Niche
Fundamental niche: the full range of conditions
under which an organism can exist.
- All resources that could be used in
absence of competition.
Niche
Realized niche: the portion of the fundamental
niche occupied in the presence of other
species.
-Resources actually used in presence of competitor.
Competitive exclusion
When forced to compete, one
species eliminates other(s)
Resource partitioning avoids
competition;
Realized niches divide resources
among several species.
Niches
F. Ecological Pyramids (Food
Chains)
Heat
Heat
Tertiary
consumers
(human)
Decomposers
Heat
10
Secondary
consumers
(perch)
100
1,000
10,000
Usable energy
Available at
Each tropic level
(in kilocalories)
Heat
Primary
consumers
(zooplankton)
Producers
(phytoplankton)
Heat
TROPHIC LEVEL
Quaternary
consumers
Carnivore
Carnivore
Tertiary
consumers
Carnivore
Carnivore
Secondary
consumers
Carnivore
Carnivore
Primary
consumers
Herbivore
Zooplankton
Producers
Plant
Phytoplankton
A TERRESTRIAL FOOD CHAIN
AN AQUATIC FOOD CHAIN
Energy Pyramids Show
•Amount of available energy
decreases for higher
consumers
•Amount of available energy
decreases down the food
chain
•It takes a large number of
producers to support a small
number of primary
consumers
•It takes a large number of
primary consumers to
support a small number of
secondary consumers
Energy Pyramids
The general
rule is that
there is
about a 10%
transfer of
energy from
trophic level
to the next.
copyright cmassengale
47
Another way to
state it: There is
a 90% energy
loss between
Trophic
Levels
Tertiary
Consumer
.1%
Secondary Consumers
1%
Primary Consumers
10%
Producers (Plants)
100%
Biogeochemical cycles
The Water Cycle
The carbon Cycle
The nitrogen Cycle
Water Cycle
Freshwater is critical for plants and animal
communities
Carbon Cycle
Life on earth is based on carbon compounds. All of
the energy-rich organic molecules of living systems
are constructed using carbon.
Nitrogen cycle
Nitrogen is an essential nutrient for
plants.
III. What is biodiversity and what
factors impact it?
A. BIODIVERSITY:
the number and types of organisms on the
earth.
The most species rich environments are…
-Tropical rain forests
-Coral reefs
-Deep sea
-Large tropical lake
*Those communities with the largest number
of different species generally have only a
few of each species or low species
abundance
Measuring Biodiversity…
Species Richness: the total number of given species
in a quantified area.
Species Evenness: the degree to which the number
of individual organisms are evenly divided between
different species of the community.
www.nature.com/cgi-taf
B. Factors that decrease biodiversity
•
•
•
•
Environmental stress
Large disturbances
Extreme conditions
Limitation of essential
resources
• Introduction of alien
species
• Geographic Isolation
C. HUMAN EFFECT ON
BIODIVERSITY
• Habitat destruction – due to
increased human population
• Illegal-hunting/poaching
• Introduction of exotic species
D. Human Impacts on Aquatic
Biodiversity
1.) Species Loss and
Endangerment
• Overfishing
• Habitat Destruction
• Pollution
1/3 of all fish species are
threatened with extinction
E. Three Types of Extinction
1. Local Extinction:
Species is no longer found in an area
it once was, but it is found in
other areas
2. Ecological Extinction:
• So few that it can no longer play
its ecological role
3. Biological Extinction:
• Species is no longer found anywhere on
the earth
Biological Extinction is Forever
• Irreversible loss of genes
Background vs. Mass Extinction
Background Extinction-
A small, naturally occurring,
low rate extinction.
Fossil records show 1-14
species a year
(Approximately 1 species /
million) 0.0001% per year
B. Mass ExtinctionA rise above the background rate,
often catastrophic and global.
Estimated to be five in the past 500
million years
Geological Periods
Number of families
of marine animals
Carboniferous
Cretaceous
Devonian
Jurassic
Silurian
Triassic
Tertiary
Ordovician
Permian
Quaternary
Cambrian
800
Mass
extinctions
600
?
400
200
0
570
505
438
360
408
286
208
245
Millions of years ago
144
65
0
2
Fig. 22.10, p. 558
Causes of Premature Extinction
1. Habitat loss, degradation, and
depletion
-In U.S. the major disturbances
are…
*agriculture/grazing
*development
*outdoor recreation
*pollution
F. What are Endangered
and Threatened Species?
Endangered:
• So few individual survivors
that the species can become
extinct over all or part of its
range
Threatened or Vulnerable:
• Still abundant in its natural
range and may become
endangered
Bushmeat
IV. General Types of Species
1. Native:
- Normally live and thrive in an
ecosystem
2. Non-native:
- Often called exotic, alien or invasive:
- Introduced species tend to crowd out
native species
- May not have any natural population
controls
Lamprey
ASIAN CARP
Battling Back Against the Asian
Carp
Snakehead Fish
3. Indicator:
- Serve as an early warning that an
ecosystem is being damaged
- Organisms that are sensitive to
environmental change or spend
the entire life cycle in the
environment
- Ex: Birds, Trout,
Frogs
4. Keystone:
- Species that have
a greater
importance in the
structure of the
community
*Controversial
among scientists
Ex: Dung Beetle,
Alligator,
Elephant, birds,
bats, top predator
Species Interactions
1.) COMPETITION
2) PREDATOR/PREY
3) SYMBIOSIS
Locked Deer
Lions Fighting
Types of Symbiotic Species
Symbiosis: Interactions
Long lasting relationship where
species live together
3 types of symbiotic relationships
A. Parasitism
B. Mutualism
C. Commensalisms
A. Parasitism
• Species feeds on part of
another organism
• Host is usually harmed
• Parasite is usually smaller
than the host
• Rarely kills the host quickly
• Endo/Ecto parasites
B. Mutualism
• 2 species are in a relationship that is
beneficial to both
• Providing Food +
Protection
C. Commensalism
• Relationship that benefits one
species but neither helps nor
harms the other
• EX:
• Epiphytes (orchids that attach to
trees)
• Raccoons/Rats
IV. Use of Water Resources
1. Availability of Water
 Humans use about 50% of reliable runoff
Agriculture
Industry
Domestic
United States
Agriculture
Power
38%
cooling
38%
Power plants
Industry 11%
Public 10%
Fig. 13.5, p. 298
Personal Water Usage
Too Little Water
According to the experts there are
four causes of water scarcity…
1. Dry climate
2. Desiccation
3. Drought
4. Water stress
-Because layers of rock frequently
slope, water will move through the
ground by way of AQUIFERS.
Flowing
artesian well
Precipitation
-
Well requiring a pump
Evaporation and transpiration
Evaporation
Confined
Recharge Area
Runoff
Aquifer
Infiltration
Stream
Water table
Infiltration
Lake
Unconfined aquifer
Less permeable material
such as clay
Confined aquifer
Confirming permeable rock layer
2. Methods of Determining
Water Quality
A. Coliform Bacteria
• 0 colonies per 100ml for drinking water
• 200 colonies per 100ml for swimming
B. Biological Oxygen Demand
(BOD)
• The amount of oxygen needed by
decomposers to break down organic
0
material over a 5-day period at 68 F
C. Dissolved Oxygen (DO)
• Only a few species of fish can survive
when the D.O. level drops below 4 ppm
Water
Quality
Do (ppm) at 20˚C
Good
Slightly
polluted
Moderately
polluted
Heavily
polluted
Gravely
polluted
8-9
6.7-8
4.5-6.7
Below 4.5
Below 4
D. Chemical
Analysis
• Determine
the levels of
organic and
inorganic
pollution
E. Indicator Species
• Indicator species can
be used to monitor
water quality
• Ex: Mussels,
Cattails, Insect larva
• Analyzed to measure
the levels of various
chemicals
3. Sources of Pollution
A. Point Sources
-Discharge from a specific
location (pipe, ditch or sewer)
-Easier to identify and regulate
Ex: Factories, Sewage
Treatment Plants, Mines,
Thermal Outlets and Oil
Tankers.
B. Non-Point Sources
-Cannot be traced to a specific
discharge
-Difficult to identify and control
Ex: Golf Courses, Agriculture,
Homes
VI. Solid and Hazardous Waste
United States and Solid
Waste…
A High-Waste Society
• 4.5% of the worlds
population makes 1/3 of
the waste
• 12 billion tons / year
• Ave 97,000lbs / year /
person in the USA
Wasting Resources
Mining and oil
and gas
production
75%
Sewage sludge
1%
Industry
9.5%
Agriculture
13%
Fig. 21.2, p. 519
Dumped in
landfills
(54%)
Municipal
1.5%
Recycled or Burned in
composted incinerators
(16%)
(30%)
Fig. 21.3, p. 519
What is Hazardous Waste
Legally defined as…
• Any waste with one or more of
39 toxic or carcinogenic
compounds that exceeds the
limits
• Catches fire easily
• Reactive enough to explode
and release fumes
• Can corrode a metal container
Dealing with Materials Use and Wastes
1st Priority
2nd Priority
Primary Pollution
and Waste Prevention
Secondary Pollution
and Waste Prevention
• Change industrial
process to eliminate
use of harmful
chemicals
• Purchase different
products
• Use less of a harmful
product
• Reduce packaging and
materials in products
• Make products that
last longer and are
recyclable, reusable or
easy to repair
Last Priority
Waste Management
• Reduce products
• Treat waste to reduce
• Repair products
toxicity
• Incinerate waste
• Recycle
• Compost
• Buy reusable and
recyclable products
• Bury waste in
landfill
• Release waste into
environment for
dispersal or dilution
Fig. 21.4, p. 521
Options for Dealing with
Hazardous Wastes
Produce Less Waste
Manipulate
processes
to eliminate
or reduce
production
Fig. 21.5, p. 522
Recycle
and
reuse
Convert to Less Hazardous or Non-hazardous Substances
Land
treatment
Incineration
Thermal
treatment
Chemical
physical, and
biological
treatment
Ocean and
atmospheric
assimilation
Put in Perpetual Storage
Landfill
Underground
injection
Waste
piles
Surface
impoundments
Salt
formations
Arid region
unsaturated
zone
Potential Solutions:
•
•
•
•
Decrease Consumption
Increase efficiency
Produce less waste and pollution
Develop products that are easy to
repair
• Eliminate unnecessary packaging
• Trash Taxes
Burning Wastes
Advantages
Reduced trash
volume
Disadvantages
High cost
Less need for
landfills
Air pollution
(especially
toxic dioxins)
Low water
pollution
Produces a
highly toxic ash
Encourages
waste production
When landfill is full,
layers of soil and clay
seal in trash
Methane storage
Topsoil
and compressor
building
Sand
Leachate
treatment system
Clay
Garbage
Methane gas
recovery
Pipe collect explosive
methane gas used as fuel
to generate electricity
Compacted
solid waste
Leachate
storage tanks
Leachate
monitoring
well
Garbage
Sand
Synthetic liner
Sand
Clay
Subsoil
Leachate pipesLeachate pumped up
to storage tanks for
safe disposal
Groundwater
Clay and plastic lining
to prevent leaks; pipes
collect leachate from
bottom of landfill
Groundwater
monitoring
well
Deep-well Disposal
Advantages
Safe method if
sites are chosen
carefully
Wastes can be
retrieved if
problems
develop
Low cost
Disadvantages
Leaks or spills at
surface
Leaks from
corrosion of well
casing
Existing fractures
or earth quakes
can allow wastes
to escape into
groundwater
Encourages
waste production
Above Ground Hazardous Waste Disposal
Waste
transporter
Elevator shaft
Hazardous waste
Support
column
Inspector
VII. Agriculture
A. WHAT IS A PEST-
• Any species that does the
following:
1.Competes with humans for
food
2.Invades lawns and gardens
3.Destroys wood in a home
4.Spreads disease
5.Nuisance
B. TYPES OF PESTICIDES
1.
2.
3.
4.
Insecticides
Herbicides
Fungicides
Nematocides (Round
worms)
5. Rodenticides
Broad vs. Narrow
• Broad Spectrum Agents:
• Toxic to many species
• Selective / Narrow Spectrum:
• Specific to a certain species
• Pesticides vary in their persistence:
• How long they remain in the
environment
1. Cultivation Practices;
•
•
•
•
crop rotation
changing planting times
planting trap crops
increasing habitat for natural
predators
2. Create Genetically Resistant
Plants;
3. Biological Pest Control;
Pro’s
Con’s
-no mass
-focus on target reproduction
-are nontoxic
-slow
-save money
-must be
protected from
spraying
-minimize
resistance
-can become a
pest
4. Insect Birth Control;
Sterilization of insects
– used with screwworms,fruit
flies
Disadvantages include…
-high cost
-estimating mating
times/behaviors
-need large # of males
-males must be reintroduced
5. Sex Attractants;
The use of pheromone
baited traps
6. Hormones to stunt
growth;
7. Spraying with hot water;
8. Exposing food to
gamma radiation
C. Basic Principles of Integrated Pest
Management (IPM)
• Know the target
• Monitor and evaluate pest populations
• Establish a threshold (what level you
can tolerate)
• Chose a tactic
• Evaluate results
The goal is not total elimination but
reduce crop damage and economic
losses
Soil: Formation Erosion, and
Conservation
A. What is Soil?
complex mixture of eroded rock, minerals,
decaying organic matter, water, air,
and living organisms.
Ratios Differ among various soil types…
Average Ratios:
45% Minerals
25% Water
25% Air
5% Humus
B. How Soil is Produced
-Weathering of rock
-Depositing of sediment
-Decomposition of matter
C. Soil Zones (MATURE)
-Soil is arranged into zones
called…
SOIL HORIZONS
-A cross-section of soil
horizons is called…
SOIL PROFILE
-Most mature soils have at
least three of the possible
horizons
LAYERS/HORIZONS
O Horizon –
Top layer/Surface Liter
Layer
-Characterized by debris and
animal waste
-Brown/black in color
A Horizon –
• Top Soil Layer
-Consists of porous mixture of
partially decomposed organic
matter called…
• HUMUS
• Inorganic minerals
-Most plant roots and organic
matter found here.
B Horizon – Subsoil Layer
and
C Horizon – Parent Material
•
Contain most of soil’s
inorganic matter and varying
mixtures of sand, silt,clay,
and gravel
• C Horizon lies on BEDROCK
Soils: zones
Immature soil
O horizon
Leaf litter
A horizon
Topsoil
Regolith
B horizon
Subsoil
Young soil
C horizon
Parent
material
Mature soil
Bedrock
D. Soil Properties
*Soils vary in content of …
Clay
Silt
Sand
Gravel
-Relative amounts of different size and
types determines SOIL TEXTURE
-LOAMS – soils of equal mixture
100%clay
0
80
20
Increasing
percentage clay
Increasing
percentage silt
60
CLAY
40
40
60
20
SAND
80
SILT
0
100%sand
80
60
40
20
Increasing percentage sand
100%silt
FORESTRY
A. Even-Aged Management:
- Trees are kept as same size and
age
-Example: Tree farms
*Extensive research in Germany has
shown that soil had become depleted
PA Forest Management
• Most of the forests are Even Aged
• Average age of trees 80-120
years
Tree Diameter & Management
• Important consideration of Even Aged
Management
• Trees of the same age may vary in
diameter
Factors that impact tree diameter:
• Variation among species growth rates
• Soil and Site conditions
• Genetics
• DBH (Diameter at Breast Height) can
be measured with a Biltmore Stick
Classifying a Forest Based on
Predominant Tree Size
3 Categories for describing tree diameter:
1.) Seedling-Sapling: DBH < 5”
2.) Mid-Size Tree: DBH 5-11”
3.) Large Tree: DBH > 11”
B. UnEven-Aged Management:
- Trees are kept at a variety of
ages and sizes
-Goals are:
1. Biological diversity
2. Long-term sustainable
production of timber
3. Moderate economical return
4. Multiple use of forests
Primary Succession
Occurs on surfaces where no
soil exists, usually after a
volcanic eruption.
1. Bare rock community is
populated by an pioneer
species (first species to
populate an area). Usually
lichens (fungus and alga).
2. Pioneer species help to
form soil and puts nutrients
into soil.
3. The stable, mature
community is called a
climax community.
Secondary Succession
Occurs in an community where everything
has been removed but the soil.
1. Primary SuccessionSuccession that occurs where no ecosystem existed
before. (Start with Rock)
Lichens
and
mosses
Exposed
Rock
Small herbs Heath mat
and shrubs
Time
Balsam fir,
Jack pine, paper birch, and
black spruce, white spruce
climax
and aspen
community
Fig. 8.15, p. 188
2.Secondary Succession –
Succession that occurs where an ecosystem previously
existed (Start with Soil)
Mature oak-hickory forest
Young pine forest
Annual
weeds
Perennial
weeds and
grasses
Shrubs
Time
Fig. 8.16, p. 189
Global Warming and The Natural
Greenhouse Effect
(a) Rays of sunlight
penetrate the lower
atmosphere and warm
the earth's surface.
(b) The earth's surface absorbs much (c) As concentrations of
of the incoming solar radiation and
degrades it to longer-wavelength
infrared radiation (heat), which
rises into the lower atmosphere.
Some of this heat escapes into
space and some is absorbed by
molecules of greenhouse gases
and emitted as infrared radiation,
which warms the lower
atmosphere.
greenhouse
gases rise, their molecules
absorb and emit more
infrared radiation, which adds
more heat to the
lower atmosphere.
Fig. 6.13, p. 128
Climate Change and Human
Activities
Since the Industrial
Revolution (1750) there
has been a sharp rise in:
1. Use of fossil fuels
2. Deforestation and burning
grasslands to raise crops
3. Cultivating rice and using
fertilizer that releases N2O
Largest Contributors to CO2
Emissions
1. Thousands of Coal
Burning power and
industrial plants
2. 700 million gasoline
burning motor vehicles
(555 million of them are
cars)
Emissions from US factories
and power plants
produce more CO2 than
the combination of 146
nations (75% of the world
population)
Are we experiencing Global
Warming?
The following facts are based on analysis of ice cores, temperature
measurements in hundreds of boreholes into the earths surface and
atmospheric temperature measurements
• CO2 concentrations are at their highest
level in the past 20 million years
• 75% of human caused CO2 emissions are
from the burning of fossil fuels
• The 20th century is the hottest in the past
1000 years
• Since 1861 the global temperature has
risen 1.1 – 0.4o F
• 10 hottest years on record have occurred
since 1990
What do the changes in climate
mean for humans?
1. Affects the availability
of water resources by
altering rates of
evaporation and
precipitation
2. Shift areas where
crops can be grown
3. Change average sea
levels
4. Alter the structure and
location of the world’s
biomes
Agriculture
•
Shifts in food-growing
areas
•
Changes in crop yields
•
Increased irrigation
demands
•
Increased pests, crop
diseases, and weeds in
warmer areas
Water Resources
• Changes in water supply
• Decreased water quality
• Increased drought
• Increased flooding
Forests
•
Changes in forest
composition and locations
•
Disappearance of some
forests
•
Increased fires from drying
•
Loss of wildlife habitat and
species
Biodiversity
Sea Level and Coastal Areas
•
Extinction of some plant
and animal species
•
•
•
Loss of habitats
•
•
Disruption of aquatic life
•
•
•
Weather Extremes
•
Prolonged heat waves
and droughts
•
Increased flooding
•
More intense
hurricanes, typhoons,
tornadoes, and
violent storms
Rising sea levels
Flooding of low-lying islands
and coastal cities
Flooding of coastal estuaries,
wetlands, and coral reefs
Beach erosion
Disruption of coastal
fisheries
Contamination of coastal
aquifiers with salt water
Human Health
Human Population
• Increased deaths
• More environmental
refugees
• Increased migration
•
Increased deaths from heat
and disease
•
Disruption of food and water
supplies
•
Spread of tropical diseases to
temperate areas
•
Increased respiratory disease
•
Increased water pollution
from coastal flooding
Fig. 18.12, p. 458
This has nothing to do with global warming!!!
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