Matter and Energy in The
Environment
LS CH 20
ECOLOGY
• The study (science) of the interactions between organisms and
their environment.
• Study of ecosystems
• Includes everything in a given area:
• Living things (biotic factors)
• Nonliving things (abiotic factors)
What do Ecologists Study?
(think-pair-share)
Abiotic Factors
• Any nonliving thing in an ecosystem
• Still impacts organisms
• Examples:
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Sunlight
Atmospheric gases
Climate
Temperature
Soil
Water
Human impacts
The Sun
• The ultimate source of energy for our planet
• Sun  Producers (photosynthesis)  Primary consumers  Secondary
consumers  etc.
• Also plays a role in many other abiotic factors
• Evaporates water
• Creates wind and weather due to heating patterns on Earth
• Controls temperature
Why do we experience seasons?
The Earth is Tilted on its Axis
• In our summer, the Northern Hemisphere tilts towards the sun,
giving us more direct sunlight and keeping it warmer
• The Southern Hemisphere tilts away, giving them winter
• In our winter, the Northern Hemisphere is tilted away from the
sun, giving us less direct sunlight (sunlight is spread out more) and
cooling it down.
• The Southern Hemisphere tilts towards the sun, giving them summer
Atmospheric Gases
• The atmosphere is the layer of gases surrounding Earth
• Atmospheric composition (learn these percentages)
• Oxygen is breathed in by many organisms, and made by others
• Nitrogen is used by many organisms
Climate and Weather
• Climate is the average weather conditions in an area over a long
period of time
• NOT THE SAME AS WEATHER!
• Includes precipitation, temperature, and wind
• Weather is the current condition
• A vast majority of scientists and researchers (97% who work in this
area of research) believe that humans are changing the climate
• Could have drastic impacts to many ecosystems
Temperature
• How hot or cold something is (sort of… at least until Physical
Science)
• Most organisms can only survive within a certain range of
temperatures
• Polar bears in the desert, cacti in Antarctica…
Soil
• Made up of rock fragments, water, air, and bits of living things
• Essential for survival of plants, and therefore all organisms
• Bacteria within the soil break down dead organisms
Water
• Availability and quality important
• Only raw material that all organisms on earth need
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All organisms are made up of water
Animals drink it to stay alive
Plants need it for energy production and photosynthesis
Marine life and many protists live in it
• While most of the earth is covered in water, it is not all in the
proper form for all organisms to use
Human Impacts
• General Theme in Ecology
• We tend to mess things up rather a lot
• Humans are biotic factors, but we create a lot of abiotic factors
• Pollution impacts ecosystems greatly
• Buildings and roads fragment ecosystems
• We also impact other abiotic factors
• Water pollution
• Climate change
Matter is cycled in nature
• Matter Cycles
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Water
Nitrogen
Carbon-Oxygen
Others we won’t be exploring
The Water Cycle
• Terms:
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Evaporation-Liquid to gas
Condensation-Gas to liquid
Precipitation-Water falling to earth’s surface
Transpiration-Water leaving plants
Exhalation-Water leaving as organisms exhale
Run-off- Water that travels over surfaces
Groundwater- The water stored underground
The Carbon-Oxygen Cycle
• Oxygen is needed by much of the life on earth
• Essential for the production of ATP during cellular respiration
• Oxygen is produced by plants and phytoplankton (includes tiny
plants, some bacteria, and some protists) during photosynthesis
• The oxygen is then taken in by organisms to allow respiration to
occur
• Provides ATP so that cells can do their jobs
• During respiration, Carbon Dioxide is produced
The Carbon-Oxygen Cycle Cont.
• Carbon is found in the air in the form of carbon dioxide
• Comes from:
• Exhalation of organisms (created in cellular respiration)
• Burning of fossil fuels
• Fossil fuels are fuels made from the remains of organisms
• Contributes significantly to climate change
• Natural release of carbon from soil
• Forest fires
• Deforestation
• Taken in by:
• Soil
• Photosynthetic organisms
CO2 As A Greenhouse Gas
• Carbon dioxide absorbs radiation from the sun
• This traps it on earth (similar to a greenhouse trapping heat), increasing global
temperatures
• Global Warming (not a myth)
• Over time, the average temperatures throughout the planet have increased
• Climate change (also not a myth. Actually very terrifying)
• Carbon Dioxide is not alone
• Other gases (especially methane) are greenhouse gases
• However, increased CO2 emissions are accelerating climate change faster than other gases
The Nitrogen Cycle
• Nitrogen is the most abundant gas in the atmosphere
• Atmospheric electricity (lightning) causes nitrogen compounds to fall to the
surface
• Nitrogen is a component of DNA and of proteins
• Organisms get nitrogen into their body by eating other organisms
• Animals release Nitrogen into the soil through waste (fertilizer)
• Also, when an organism dies, bacteria decompose the organism and turn the
nitrogen into forms that plants can use
• They also release nitrogen from the soil back into the atmosphere
Movement of Energy in an Ecosystem
• Every living thing needs energy
• The ultimate source of energy is the sun
• Also a little bit of energy from Earth’s interior and hydrothermal vents in
the ocean
• The Law of Conservation of Energy
• Energy cannot be created or destroyed. It can change forms. (More Physical
Science!)
Types of Organisms (Review)
• Producers
• Able to make their own “food” (energy sources)
• Can be done by photosynthesis or chemosynthesis
• Chemosynthesis is like photosynthesis, only it uses chemical energy instead of sunlight
• Occurs near hydrothermal vents
• Often uses sulfur compounds
• Consumers
• Organisms that must consume food to get energy
• Classified by type of food sources
Classifications of Consumers
• Herbivores
• Eat only plants
• Carnivores
• Mostly eat other animals
• Omnivores
• Able to eat both plants and animals
• Humans, regardless of their diet, are omnivores
• Decomposers
• Feed on dead or decaying organisms
Transferring Energy in an Ecosystem
• It all starts with the sun (or hydrothermal vents in some oceanic
ecosystems)
• Producers capture the sunlight and use it to make sugars
• Consumers then eat the producers, collecting the sugars
• Consumers and producers eventually die, and provide energy for
decomposers
• At each level, only about 10% of the energy is able to go on to the
next level
• Around 90% of the energy is used by the organism
• Cannot be destroyed
• Transferred to the environment as heat due to metabolism
Modeling Energy Transfer
• Food chains
• Very simple diagram showing one way that energy can be transferred
• Not even close to complete
• Very simplistic. Your teacher is not a fan…
• Food Web
• A more complex diagram showing many (or ideally all of) the feeding
relationships in an ecosystem
• Can still be sort of simple
• Can be extremely complex
• In either case, the arrows point to WHERE THE ENERGY IS
GOING!
Energy Pyramids
• A different sort of diagram, related to the others
• Shows how much energy is passed on to the next level
Food Web Drawing
• Requirements
• Must include the sun (NOT AN ORGANISM!)
• 10 organisms (must be real, and must live in same ecosystems (i.e. no dragons,
bigfoot, etc., and no sharks in a desert ecosystem. Questions, ask!)
• At least 1 each of the following:
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producer
herbivore
carnivore
decomposer
• Label each organism with its common name, and what type of organism it
is (producer, consumer, etc.)
• Must be neat and include appropriate colors.