Transcript Ecology - Onondaga Community College

Ecology
Ecology
• Organisms – all living things
• Environment – everything that surrounds or
affects an organism, living and nonliving,
like light, heat, soil, water and air
• Ecology – the study of living things and
their relationship to their environment
Requirements for Life
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Liquid water
Carbon and other chemical elements
Gravity to retain our atmosphere
Continuous and unwavering energy supply
Other important factor
• Magnetic field (to protect from solar particles)
Ecosystem
• A group of organisms
interacting with each other and
their surroundings
• Distinguished by different climate, soil, vegetation
and animals
• Maintains a balance (that can be fragile)
• The largest terrestrial ecosystems are
biomes
• Recognized by their similar characteristics
– Examples: Deserts, temperate forests, tropical
rain forests, oceans, mountains, grasslands,
rivers, and lakes
Community
• A group of living things within an ecosystem
• Relatively small changes can change or upset the
balance of the community and begin a process of
change
• Species – a group of animals that are able to breed
freely and produce fertile offspring (further
definition maybe necessary in some cases - DNA)
• Population – members of the same species sharing
a habitat
• Habitat – an environment with certain
characteristics
• Niche – the effects an organism has on its
surroundings and how the surroundings affect the
organism
• Ecological succession – orderly progression of
changes producing a stable or climax community
e.g. weeds, grass, shrub, forest
Food Chain
• Each organism is food for the next in line
• All energy originates from the Sun
• Producers or autotrophs convert this energy to
organic molecules
• Consumers or heterotrophs - eat other organisms
• Primary consumers eat plants
• Secondary and tertiary eat the herbivores
and carnivores respectively
• Omnivores - eat both plants and animals
• Decomposers - eat dead organic material
Food Web
• Because few organisms eat one kind of food
• Bioaccumulation - the storage of chemicals
within an individual organism at higher
levels than those found in the environment
• Biomagnification – when chemicals
accumulate at increasingly higher
concentrations at successive levels of the
food chain
Energy Flow
• Trophic level – level of energy consumption
within the food web
• T1 – producers
• T2 – primary consumers
• T3 – secondary consumers
Energy (an aside)
• The ability or capacity to do work
• Heat, electrical, mechanical or chemical
• Potential energy is stored and available to do work
• Kinetic energy is called the energy of motion
Laws of Thermodynamics
• The study of energy, its functions and
transformations
• Energy flow from one trophic level to the next
results in a significant loss of usable energy
• Most energy is used by an organism for movement
and digestion etc.
• Just 10 – 15% is stored for use by the next
predator
Ecological Pyramids (Fig. 4-5)
• Numbers – how many organisms occupy each level
• Biomass
• Energy
• At each trophic
level there is a
90% reduction in
biomass and energy
The Carbon Cycle
• Biochemical cycle – ties living organisms to
the physical environment
• Carbon is contained in over 80% of all
known compounds
• Photosynthesis converts CO2 and H2O to
make glucose C6H12O6
Carbon Cycle II
• Long term carbon cycle involves longer term
geologic processes; with time frames in the
thousands and millions of years
Long term Carbon Cycle
Carbon Cycle III
• Shorter biological carbon cycle; involves
processes whose time frames are in 10’s of years
to thousands of years
Short term Carbon Cycle
Carbon Cycle IV
• Relationship between
shorter & longer term
cycles is complex
• Involves several feed
back loops between
the two cycles
Carbon Cycle V
Human impact
on carbon
cycle
Nitrogen Cycle
• The circulation of nitrogen through plants
and animals and back to the atmosphere
• 78% of the atmosphere by volume
• Essential for the manufacture of proteins
and other molecules vital for growth and
reproduction
• Nitrogen from the atmosphere is removed
by nitrogen fixation carried on by some
bacteria, algae and lichens and turned into
ammonia, nitrates and nitrites
• These substances can be taken up by plant
roots and used to manufacture proteins
• Nitrogen compounds return to the soil as
animal waste and through the decay of dead
plants and animals
• Denitrifying bacteria return the nitrogen to
the atmosphere by breaking down nitrites
The Hydrologic Cycle
• Describes water’s circulation through the
environment
• Only 2% of water taken in by plant roots is
used in photosynthesis, the rest is released
to the atmosphere in a process called
transpiration
Ecological Concerns
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Acid deposition (acid rain) & mercury
Ozone depletion
Species loss
Global warming
Population (human) increase
Ecological Concerns II
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Soil erosion
Food and water demands
Deforestation
Energy use
Dwindling mineral resources
• Rain with a pH of less than 5.6 is considered acid
rain
• Acid precipitation problems are noticed first in
aquatic systems because soils have a much greater
buffering capacity
• Acid deposition can leach nutrients from the soil,
hamper microorganisms that nourish plants and
release toxic metals
Ozone Depletion
• CFC’s and halons are breaking down the
ozone molecules in the upper atmosphere
• Increased UV rays cause more cases of skin
cancer, decreased crop yields, reduces the
population of certain fish larvae, and
reduces the life of outdoor paints and
plastics
Global Warming
Change in global climate due to greater retention of
planetary surface heat; due to:
• Burning fossil fuels (coal, oil, gas) & other
combustible fuels (creating green house gases like
CO2, methane, etc.)
• Clearing the rainforest, and agricultural practices
• Environmental feedbacks, methane & CO2
Global Heat Balance for Surface of
the Planet
Energy balance:
• Incoming radiation
(visible & UV)
• Heat mixing &
distribution
• Outgoing surface
radiation (IR)
Global temperature change
Temperature (o Celsius)
The gray represents uncertainty
• Global temperatures have risen over the last century and
evidence indicates they continue to rise
• Global warming results in climate change, that alter global
weather patterns and regional climates
• Sea level has risen nearly 8” in the last century and further
rises will inundate coastal wetlands, erode recreational
beaches and increase salinity of estuaries and groundwater
• Impacts also include the pH of the worlds oceans having
impacts on oceanic life (e.g. coral reefs)
Temperature variation over the last 160 thousand
years as recorded in Greenland ice core data
Greenland Ice Cores
• Oxygen isotopes in the ice tell
us the atmospheric temperature
at each time
• Trapped air in the ice tells us the
composition of the atmosphere
at each time
Air bubbles
Species Loss
• Biologic diversity – variety and variability
among living organisms and ecological
complexes
• Ecosystem diversity
• Species diversity
• Genetic diversity
• Estimates of total species are approaching
30 million
• We are losing 17,500 per year
• Many are untapped resources for
agricultural, industrial and medicinal
development
Wetlands and Rainforests
• 55% of wetlands in the US have been
converted for industrial, residential and
agricultural purposes
• Although rainforests cover only 7% of the
earth’s surface they harbor over 50% of the
world’s plant and animal species
Benefits of Sustaining Wetlands
• Species diversity
• Flood control
• Filtration
Benefits of the Rainforests
• Absorb rainfall and release moisture into the
atmosphere affecting the world’s weather patterns
• Absorbs a large percentage of the world’s CO2
emissions
• Controls soil erosion and landslides
• Creates essential oxygen
• Moderates the effects of floods and droughts
Environmental Protection (NEPA)
• National Environmental Policy Act (1970)
• States our intent to achieve productive and
enjoyable harmony between the activities of
humans and the environment
NEPA II
• Implemented by the EPA
• No enforcement agency, lawsuits from
outside the government
• Established the Council of Environmental
Quality – CEQ overseeing federal
environmental issues
Environmental Assessment
(under NEPA)
• Study of any governmental actions
• May result in the filing of a Finding of No
Significant Impact – FONSI
• Or an Environmental Impact Statement – EIS,
must be prepared for any project if government
funding or regulations are involved
NEPA III
• The EPA is a major reviewer of EIS’s
• The input and disclosure process built into NEPA
give the public an opportunity to participate in the
decision-making process
• Many states have statutes that parallel NEPA (New
York State, SEQR – State Environmental Quality
Review Act)