2. Core Case Study:
Tropical Rainforests Are Disappearing (1)
• Found near the equator
• 2% land surface
• ~50% world’s known terrestrial plant and
animal species
• ≥50% destroyed or disturbed by humans
– Cutting trees
– Growing crops
– Grazing cattle
– Building settlements
3. Core Case Study:
Tropical Rainforests Are Disappearing (2)
• Consequences of disappearing tropical
rainforests
1. Decreased biodiversity as species become
extinct
2. Accelerated global warming: fewer trees to
remove carbon dioxide from the atmosphere
3. Changes regional weather patterns: can lead
to increase in tropical grasslands
5. 3-1 What Keeps Us and Other
Organisms Alive?
• Concept 3-1A The four major components
of the earth’s life-support system are the
atmosphere (air), the hydrosphere (water),
the geosphere (rock, soil, sediment), and
the biosphere (living things).
• Concept 3-1B Life is sustained by the flow
of energy from the sun through the
biosphere, the cycling of nutrients within
the biosphere, and gravity.
6. Earth Has Four Major Life-
Support Components
• Atmosphere
• Hydrosphere
• Geosphere
• Biosphere
8. Fig. 3-2, p. 41
Rock
Crust
Atmosphere
Vegetation
and animals
Biosphere
Mantle
Lithosphere
Soil
Geosphere
(crust, mantle, core)
Mantle
Core
Crust
(soil and rock)
Biosphere
(living organisms)
Atmosphere
(air)
Hydrosphere
(water)
9. Three Factors Sustain Life on
Earth
• One-way flow of high-quality energy
from the sun
• Cycling of matter or nutrients through
parts of the biosphere
• Gravity
10. Solar Energy Reaching the
Earth
• Electromagnetic waves
–Visible light
–UV radiation
–Heat
• Natural greenhouse effect
• Energy in = energy out
• Human-enhanced global warming
12. Solar
radiation
Radiated by
atmosphere
as heat
Reflected by
atmosphere
Most
absorbed
by ozone
Absorbed
by the earth
Greenhouse
effect
Visible
light
UV radiation
Heat radiated
by the earth
Heat
Troposphere
Lower Stratosphere
(ozone layer)
Fig. 3-3, p. 41
13. 3-2 What Are the Major
Components of an Ecosystem?
• Concept 3-2 Some organisms
produce the nutrients they need,
others get the nutrients they need by
consuming other organisms, and
some recycle nutrients back to
producers by decomposing the
wastes and remains of organisms.
14. Ecology
• How organisms interact with biotic
and abiotic environment
• Focuses on specific levels of matter:
–Organisms
–Populations
–Communities
–Ecosystems
–Biosphere
16. Smallest unit of a chemical element
that exhibits its chemical properties
Biosphere
Ecosystem
Community
Population
Organism
Cell
Molecule
Atom
Parts of the earth's air,water, and soil
where life is found
A community of different species
interacting with one another and with
their nonliving environment of matter
and energy
Populations of different species
living in a particular place, and
potentially interacting with each
other
A group of individuals of the same
species living in a particular place
An individual living being
The fundamental structural and
functional unit of life
Chemical combination of two or
more atoms of the same or different
elements
Fig. 3-4, p. 42
Water
Hydrogen Oxygen
17. Smallest unit of a chemical element
that exhibits its chemical properties
Atom
Molecule Chemical combination of two or
more atoms of the same or different
elements
Cell
The fundamental structural and
functional unit of life
Organism An individual living being
Population A group of individuals of the same
species living in a particular place
Community Populations of different species
living in a particular place, and
potentially interacting with each
other
Stepped Art
Ecosystem A community of different species
interacting with one another and with
their nonliving environment of matter
and energy
Biosphere Parts of the earth's air,water, and soil
where life is found
Fig. 3-4, p. 42
23. Trophic Levels (2)
• Decomposers
–Release nutrients from the dead bodies
of plants and animals
• Detrivores
–Feed on the waste or dead bodies of
organisms
25. Time
progression Powder broken down by
decomposers into plant
nutrients in soil
Mushroom
Wood
reduced
to powder
Dry rot
fungus
Termite and
carpenter
ant work
Decomposers
Detritus feeders
Carpenter
ant galleries
Bark beetle
engraving
Long-horned
beetle holes
Fig. 3-6, p. 44
26. Production and Consumption of
Energy
• Photosynthesis
• Carbon dioxide + water + solar
energy glucose + oxygen
• Aerobic respiration
• Glucose + oxygen carbon dioxide
+ water + energy
27. Energy Flow and Nutrient
Recycling
• Ecosystems sustained through:
–One-way energy flow from the sun
–Nutrient recycling
31. Science Focus: Invisible
Organisms (2)
• Microbes can cause disease
–Malaria
–Athlete’s foot
• Microbes are also beneficial
–Intestinal flora
–Purify water
–Phytoplankton remove carbon dioxide
from the atmosphere
32. 3-3 What Happens to Energy in
an Ecosystem?
• Concept 3-3 As energy flows through
ecosystems in food chains and webs,
the amount of chemical energy
available to organisms at each
succeeding feeding level decreases.
33. Energy Flow in Ecosystems
• Trophic levels
• Food chain
–Sequence of organisms, each of which
serves as a source of food for the next
• Food web
–Network of interconnected food chains
–More complex than a food chain
38. Usable Energy by Trophic Level
• Energy flow follows the second law of
thermodynamics – energy lost as
heat
• Biomass decreases with increasing
trophic level
• Ecological efficiency – typically 10%
• Pyramid of energy flow
41. 10
Heat
Tertiary
consumers
(human)
Usable energy available
at each trophic level
(in kilocalories)
Heat
Secondary
consumers
(perch)
100
Heat
Decomposers
Heat
Primary
consumers
(zooplankton)
1,000
Heat
Producers
(phytoplankton)
10,000
Stepped Art
Fig. 3-10, p. 47
42. Two Kinds of Primary
Productivity
• Gross primary productivity (GPP)
• Net primary productivity (NPP)
• Planet’s NPP limits number of
consumers
• Humans use, waste, or destroy 10-
55% of earth’s total potential NPP
• Human population is less than 1% of
total biomass of earth’s consumers
44. Temperate forest
Aquatic Ecosystems
Open ocean
Continental shelf
Lakes and streams
Estuaries
Terrestrial Ecosystems
Extreme desert
Desert scrub
Tundra (arctic and alpine)
Temperate grassland
Woodland and shrubland
Agricultural land
Savanna
Northern coniferous
forest (taiga)
Swamps and marshes
Tropical rain forest
Fig. 3-11, p. 48
Average net primary productivity (kcal/m2/yr)
800 1,600 2,400 3,200 4,000 4,800 5,600 6,400 7,200 8,000 8,800 9,600
45. 3-4 What Happens to Matter in
an Ecosystem?
• Concept 3-4 Matter, in the form of
nutrients, cycles within and among
ecosystems and in the biosphere, and
human activities are altering these
chemical cycles.
47. Hydrologic Cycle
• Water cycle is powered by the sun
1. Evaporation
2. Precipitation
3. Transpiration - evaporates from plant
surfaces
• Water vapor in the atmosphere comes
from the oceans – 84%
• Over land, ~90% of water reaching the
atmosphere comes from transpiration
49. Increased
flooding
from wetland
destruction
Condensation
Evaporation
from ocean
Climate
change
Infiltration
and percolation
into aquifer
Condensation
Ocean
Lakes and
reservoirs
Ice and
snow
Surface
runoff
Surface runoff
Aquifer
depletion from
overpumping
Point
source
pollution
Reduced recharge of
aquifers and flooding
from covering land
with crops and
buildings
Groundwater
movement (slow)
Runoff
Precipitation
to land
Precipitation
to ocean
Transpiration
from plants
Evaporation
from land
Fig. 3-12, p. 49
Processes
Processes affected by humans
Reservoir
Pathway affected by humans
Natural pathway
50. Science Focus: Water’s Unique
Properties (1)
• Holds water molecules together –
hydrogen bonding
• Liquid over a wide temperature range
• Changes temperature slowly
• Requires large amounts of energy to
evaporate
51. Science Focus: Water’s Unique
Properties (2)
• Dissolves a variety of compounds
• Filters out UV light from the sun
• Adheres to a solid surface – allows
capillary action in plants
• Expands as it freezes
52. Carbon Cycle
• Based on carbon dioxide (CO2)
• CO2 makes up 0.038% of atmosphere
volume
• Major cycle processes
– Aerobic respiration
– Photosynthesis
– Fossil fuel combustion and deforestation
• Fossil fuels add CO2 to the atmosphere
and contribute to global warming
57. Nitrogen
in atmosphere
Nitrogen
loss to deep
ocean sediments
Nitrogen oxides
from burning fuel
Nitrates
from fertilizer
runoff and
decomposition
Nitrogen
in ocean
sediments Ammonia
in soil
Volcanic
activity
Electrical
storms Nitrogen
in animals
(consumers)
Bacteria
Nitrate
in soil
Nitrogen
in plants
(producers)
Nitrification
by bacteria
Denitrification
by bacteria
Uptake by plants
Decomposition
Fig. 3-14, p. 52
Processes
Reservoir
Pathway affected by humans
Natural pathway
58. Phosphorus Cycle
• Does not cycle through the
atmosphere
• Obtained from terrestrial rock
formations
• Limiting factor on land and in
freshwater ecosystems
• Biologically important for producers
and consumers
63. Fig. 3-16, p. 54
Refining
fossil fuels
Sulfur
in animals
(consumers)
Sulfur
in plants
(producers)
Sulfur dioxide
in atmosphere
Sulfur
in soil, rock
and fossil fuels
Sulfur
in ocean
sediments
Dimethyl
sulfide
a bacteria
byproduct
Processes
Reservoir
Pathway affected by humans
Natural pathway
Decay
Sulfuric acid
and Sulfate
deposited as
acid rain
Uptake
by plants
Decay
Mining and
extraction
Burning
coal
Smelting
64. 3-5 How Do Scientists Study
Ecosystems?
• Concept 3-5 Scientists use field
research, laboratory research, and
mathematical and other models to
learn about ecosystems.
65. Field Research
• Collecting data in the field by
scientists
• Remote sensing devices
• Geographic information systems
(GIS)
66. Laboratory Research
• Simplified model ecosystems
– Culture tubes
– Bottles
– Aquariums
– Greenhouses
– Chambers with controllable abiotic factors
• How well do lab experiments correspond
with the greater complexity of real
ecosystems?
67. Scientific Studies of
Ecosystems
• Models
–Mathematical
–Computer simulations
• Models need to be fed real data
collected in the field- baseline data
• Models must determine relationships
among key variables
68. Baseline Data to Measure
Earth’s Health
• Needed to measure changes over
time
• Lacking for many ecosystems
• Call for massive program to develop
baseline data
