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Environmental Science
PS 6.3-6.6
Standards
 B-6.3 Illustrate the processes of succession in an ecosystem
 B-6.4 Exemplify the role of organisms in the geochemical
cycles (including the cycles of carbon, nitrogen, and water).
 B-6.5 Explain how ecosystems maintain themselves through
naturally occurring processes (including maintaining the
quality of the atmosphere, generating soils, controlling the
hydrologic cycle, disposing of wastes, and recycling
nutrients).
 B-6.6 Explain how human activities (including population
growth, technology, and consumption of resources) affect the
physical and chemical cycles and processes of Earth.
Vocabulary
 Agriculture Technology
 Alternative Energy
 Carbon Cycle
 Carrying Capacity
 Consumption of Resources
 Denitrification
 Deposition
 Ecological Succession
 Geochemical Cycles
 Geosphere
 Greenhouse Effect
 Hydrologic Cycle
 Industrial Technology
 Nitrogen Cycle
oNitrogen Fixation
oNon-Renewable Resources
oOzone Layer
oPioneer Species
oPopulation Growth
oPrimary Succession
oRenewable Resources
oSecondary Succession
oSink
oSoil Erosion
oSustainability
oTechnology
oWater Cycle
Section 1: Succession in Ecosystems
1) Succession is a series of changes in an
ecosystem when one community is
replaced by another community because of
changes in biotic and abiotic factors.
a) Succession occurs in all ecosystems.
2. Primary Succession
a) Takes place in an area that has not been
inhabited before by plants and animals
i. Examples: rock surfaces formed by lava,
rocks scraped clean by glaciers, and city
streets
Primary Succession
Begins with organisms that can grow without soil
b)
Lichens and some mosses break down rocks into smaller
species. These are examples of pioneer species.
ii. When there is enough soil and nutrients small plants start to
grow and break the rock down further which makes more
soil.
iii. Seeds from other plants and small trees grow.
iv. As species grow and die their decomposed bodies add
nutrients to the soil and even larger plants are able to
populate the area.
i.
Lichen
http://frankwinters.wordpress.com/2007/01/09/lettuce-lichen-and-henry-david-thoreau/
http://www.thbfarm.com/Gardens_for_Nature.html
http://commons.wikimedia.org/wiki/File:Lichen_DSC00612.JPG
Primary Succession
3) Secondary Succession
a) Begins in an area where there used to be an
community and has well-formed soil
b) Examples: abandoned farmland, empty lots, clear-cut
forest areas, areas burned by forest fires.
Secondary Succession
c) When something like a hurricane, wildfire, or
human activities destroys a community
secondary succession takes place.
i. It is like primary succession in the later
stages after soil has formed.
ii. When the disturbance is over, the ecosystem
restores the original condition of the
community.
Secondary Succession
d) Occurs faster than primary succession because
soil is already present
i. When disturbances happen often or are
intense, the area will mostly have the species
that are present in the early stages
ii. When disturbances are moderate, the area
will have habitats at different stages.
Section 2 – Biogeochemical Cycles
Biogeochemical Cycles
Biogeochemical cycles are the movement
of forms of matter through the living and
nonliving parts of an ecosystem.
a) Matter changes forms but is never
created or destroyed.
b) In biological systems matter is used over
and over again in different forms.
1)
2) Carbon Cycle
a) Carbon is the major part of
biochemical compounds.
b) Carbon is the major part of living
things (proteins, carbohydrates,
lipids, nucleic acids).
Carbon Cycle
c) Carbon is found in the atmosphere and in many
minerals, rocks, and fossil fuels (gas, petroleum,
coal).
carbon
dioxide
in air combustion
respiration
photosynthesis
respiration
decomposition
of organisms
fossil fuels
photosynthesis
carbon dioxide
dissolved in water
Anything that stores carbon is called a
sink.
i.
Oceans are the Earth's largest carbon
sinks
ii. Plants and soil are also carbon sinks.
d)
Carbon Cycle
e) Ways Carbon is Recycled
Photosynthesis
1) Plants and other photosynthetic organisms use
carbon dioxide from the atmosphere and turn it into
simple sugars.
ii. Respiration
1) Organisms (like us!) break down glucose in our
bodies and carbon dioxide (CO2) is released into the
atmosphere when we breath out.
i.
Carbon Cycle
Decomposition
1) When organisms die, decomposers break
the bodies down into carbon compounds
that enrich the soil and are eventually
released into the atmosphere as CO2.
iv.
Conversion of biochemical compounds
1) Organisms store carbon as carbohydrates,
proteins, lipids (fats), and nucleic acids in
their bodies.
iii.
Carbon Cycle
v. Other ways carbon may be released:
1) Combustion: Burning of wood or fossil fuels
– this releases Co2 into the atmosphere.
2) Weathering of rocks: Bones and shells fall to
the bottom of oceans or lakes and become a
part of the rocks, such as calcium carbonate.
When these sedimentary rocks weather,
carbon is released into the ocean and
eventually into the atmosphere.
3) Nitrogen Cycle
a) Nitrogen is needed to build proteins
in organisms and is found in
materials that compose soil and
aquatic sediments.
b) Elemental nitrogen (N2) is found in
the atmosphere
Nitrogen Cycle
Ways organisms recycle nitrogen:
i. Nitrogen-Fixation
1) Nitrogen-fixing bacteria which live in the soil, roots
of plants, and aquatic ecosystems, convert nitrogen
from the air into forms that plants can use
ii. Intake of nitrogen into organisms
1) Plants take in nitrogen through their roots in the
form of ammonia and nitrate. This is how nitrogen
enters the food chain.
c.
Nitrogen Fixation
Bacteria live in these little
nodules
http://www.jic.ac.uk/corporate/about/publications/advances/issue_6.html
A bunch of bacteria in a root
nodule
http://io.uwinnipeg.ca/~simmons/16cm05/1116/16monera.htm
Nitrogen Cycle
iii. Decomposition
1) When an organism dies or from animal waste,
decomposers return nitrogen to the soil.
nitrogen
in in
nitrogen
atmosphere
atmosphere
animals
animals
plant
plant
nitrates
nitrates
nitrogen-fixing
nitrogen-fixing
bacteria
in in decomposers
nitrifying
bacteria
decomposers
nitrifying
roots
bacteria
roots
bacteria
ammonification
ammonification
nitrites
nitrites
nitrogen-fixing
nitrogen-fixing
ammonium
bacteria
in soil
ammonium
bacteria
in soil
nitrifying
nitrifying
denitrifying
denitrifying
bacteria
bacteria
bacteria
bacteria
Nitrogen Cycle
iv.
Denitrification
1) Denitrifying bacteria break down nitrogen
compounds in the soil and release it into the
atmosphere.
4. Water Cycle (Hydrologic Cycle)
water is necessary for all life processes in
living things.
b) Water is in the atmosphere, surface of the
earth, underground, and in organisms.
c) The water cycle is driven by the heat
from the sun because it causes
evaporation
a)
Water Cycle (Hydrologic Cycle)
precipitation
condensation
transpiration
lake
groundwater
surface
runoff
evaporation
water storage
in ocean
Water Cycle (Hydrologic Cycle)
d)
i.
Ways organisms recycle water:
Intake of water
1) Organisms use water to perform life functions
ii.
Transpiration
1) The release of water back into the atmosphere by plants
iii.
Respiration
1) Organisms produce water as a by-product of metabolizing
food
iv.
Elimination
1) Organisms need water to help with eliminating wastes
Section 3 – Ecosystem Care
1) Naturally occurring processes on Earth are needed to
help ecosystems to maintain the materials that
organisms need.
2) The earth is made of 4 parts:
biosphere (inhabited by life)
b) Atmosphere
c) Hydrosphere
d) Geosphere
a)
i.
These systems must interact efficiently for an ecosystem to maintain
itself
3.) Maintaining the Quality of the
Atmosphere
Oxygen and carbon dioxide are cycled through the
atmosphere
a)
i.
b)
Plants use carbon dioxide in the air to make their food and
give off oxygen as a waste product
Animals use the oxygen for respiration and release carbon
dioxide as a waste product.
oxygen
photosynthesis
respiration
carbon
dioxide
Maintaining the quality of the
atmosphere
d) The oxygen produced during photosynthesis is
also used to make up the ozone layer which
protects the biosphere from the Sun’s radiation.
e) Water also maintains the atmosphere
i.
When water vapor condenses, dust and other
particles are removed from the atmosphere and falls
with the rain or snow. (The air gets cleaned!)
4. Greenhouse Effect
Carbon dioxide, oxygen, and water vapor trap heat energy
to help maintain Earth’s temperature
b) Greenhouse gases do not let heart to pass through them
very well, so heat that the Earth releases stays trapped
c) The amount of carbon dioxide depends on how much
photosynthetic organisms are absorbing it.
a)
Greenhouse Effect
Amount of
CO2 in the
atmosphere
Greenho
use effect
Average
Global
Temperatu
re
Plant
cover on
earth
Rate of
photosynthe
sis
Amount of
CO2 absorbed
by plants
Amount of
CO2 in the
atmosphere
Higher
Increases
Increases
Increases
Increases
Increases
Decreases
Lower
Decreases
Decreases
Decreases
Decreases
Decreases
Increases
5) Global Warming
a) Global warming is the trend of increasing global
temperatures
b) Scientists believe the increased temperatures are
from greenhouse gases given off by industry and
automobiles
c) Global warming is a hotly debated topic - some
scientists believe global warming is a result of
climate patterns
d) There is concern over how these temperature
changes will affect ecosystems and especially
biodiversity
6) Air Pollution
a)
Most air pollution comes from the burning of fossil fuels such
as gas and oil.
i. Smog is air pollution that results from the interaction of
sunlight and pollutants including particulates (tiny
particles of dust, metal, and fuel).
ii. Acid rain is a type of precipitation produced when
pollutants cause the rain's pH to drop (makes it more
acidic).
1) Acid rain makes lakes and streams more acidic,
threatening water supply and the habitats of many
species. It also damages plants.
7) Generating Soils
Soil is part of the geosphere – they are always being
formed and eroded
b) Soil is made of: minerals, organic matter, water, and air
c) Soil is formed from by weathering of inorganic materials by
wind, water, and ice and the decoying of organic materials
a)
Generating Soil
Wind, water, and ice cause soil
erosion and deposition which
moves soil from one place to
another
Plants help keep the process of
soil production to be
consistent with the process of
soil erosion
d)
e)
I.
f)
The plants roots hold the dirt
in place, and also block wind
from blowing the dirt)
Soil is needed for succession to
take place.
8) Controlling the Hydrologic Cycle
This cycle is maintained by the sun and weather
b) It purifies water:
a)
Evaporated water has no impurities
ii. Water that seeps through soil and rock is filtered of
impurities
iii. As water flow slows, heavier particles settle out which leaves
purified water to travel to the ocean
i.
c)
Water Pollution
i. Runoff from farms and cities may contain toxic chemicals
and trash that can disrupt the stability of freshwater lakes
and streams.
1) Ex. fertilizers from farms can cause algae overgrowth
which lowers the amount of oxygen for the fish
2) An indicator species gives a sign that an ecosystem is
being affected such as frogs with deformities from
coming into contact with toxic chemicals
3) Biomagnification takes place when a pollutant moves up
the food chain as predators eat prey. The species at the
top are affected the most.
9) Disposing of Waste & Recycling
Nutrients
Waste materials from organisms are decomposed by
bacteria or other organisms
b) Nutrients cycle from organisms to the environment and
back by the geochemical cycles
a)
10. Human Roles in Geochemical
Cycles
a) People depend on the resources and cycles on
earth to provide clean water, clean air, and soil
that can support crops.
b) Human activities such as population growth,
technology, and using resources affect the cycles
and processes on earth.
Section 4 – Population Growth
1. Carrying Capacity
Energy, water, oxygen, and nutrients determine the
carrying capacity of humans on earth.
2) In order for humans to have sustainability, there needs to
be a balance between Earth’s resources and carrying
capacity, the needs of humans, and the needs of other
species on earth
1)
2. Population Growth
Population growth has grown exponentially
b) The population rate naturally slows as the Earth nears
carrying capacity as the death rate increases and the birth
rate decreases due to:
a)
Food and water shortages
ii. Pollution
iii. Disease
i.
http://www.treehugger.com/files/2009/05/world-population
-growth-good-news-asia-pacific-rates-starting-to-decline.php
myafrica.wordpress.com
http://serc.carleton.edu/quantskills/methods
/quantlit/popgrowth.html
3. Increasing Population Problems
Clean water runs low if water is being used up faster than
it can be purified
b) More waste is produced than can be managed. Can also be
expensive to deal with
c) Fertile soil for agriculture is lost when land is cleared
a)
i.
Worldwide demand for land has led to deforestation
Increasing Population Problems
d)
Areas of the world with very high populations have low
amounts of fertile soil, clean water, and available land. This
affects the water, nitrogen, and carbon cycles as well as soil
regeneration.
http://www.bnvillage.co.uk/news-politics-village/101777-does-obama-administration-want-reduceafrica-s-population.html
Section 5 - Human Activity on Earth
1. Technology
Technology applies scientific knowledge to find solutions
and develop products that meet the needs of humans.
Technology has helped humans, but has also caused
pollution.
b. Now humans depend on technology to provide cleaner
ways to deal with waste and to clean up pollution.
c. Technology agriculture and industry can either have a
positive or negative impact on Earth.
a.
2. Agricultural Technology
Technology has improved
the ability to grow crops
to sustain a growing
world population.
b) Sustainable practices can
conserve fertile soil and
reduce erosion
a)
Agricultural Technology
Farm machinery use
nonrenewable resources
and can contribute to
erosion and air pollution.
d) Fertilizers, pesticides,
fungicides, and livestock
waste can change the soil
and have both positive or
negative effects on the
different cycles we are
learning about.
c)
3) Industrial Technology
Industrial technology has helped to develop
communication, transportation, and industry.
b) Certain chemicals like CFCs can deplete the ozone layer.
The ozone layer helps protect the earth form ultraviolet
waves.
c) Getting rid of old technological equipment has become a
problem.
a)
 CFCs were once used in air
conditioners
Industrial Technology
Burning fossil fuels is needed for industry and
transportation and helps sustain the growing human
population; however:
d)
i.
ii.
It increases greenhouse gases (carbon dioxide) which many
scientists believe increase global temperatures
It produces acid rain.
4) Alternative Technology
Using natural renewable resources (wind, water,
geothermal, or solar energy) decreases the burning of fossil
fuels
b) Nuclear energy is another energy source. A big problem
with nuclear energy is where to store the waste produced.
a)
5) Consumption of Resources
As the population increases and technology expands, the
need for resources increases. There is only a limited
supply.
b) Resources such as food, clean water, and timber are
renewable.
a)
i.
ii.
Renewable resources have factors that limit their production
Ex: growing grain requires land, fertile soil, and clean water
Consumption of Resources
Nonrenewable resources cannot be produced at the rate
they are consumed
c)
i.
ii.
d)
Minerals and metals are important for industry but are
decreasing in availability
Minerals are formed so slowly that they take to long to
replace
Sustainable use of resources can be accomplished by not
using them as much, reusing products, and recycling waste.