Transcript Ecology: Energy Flow and Nutrient Cycles

Ecology:
Energy Flow
and Nutrient
Cycles
Essential Questions:
How does Energy Flow through the Earth?
How do Nutrients Cycle through the Earth?
How are these processes related to each other to
sustain life on Earth?
What is Energy? Recap!
• Remember the source of all energy comes from the
Sun.
• Also, one requirement of all living things is to use
energy for cell processes!
Autotrophs trap that energy and convert it into chemical
energy (sugar) through photosynthesis.
Heterotrophs obtain that energy by consuming autotrophs or
other heterotrophs and release it through cellular respiration.
• How do we Calculate and Show how that energy is
distributed through nature?
– First we need to know what energy flow is.
– Then how energy flows through the Earth.
What is Energy Flow?
• Energy and matter passes through ecosystems
when organisms metabolize other organisms.
Key Vocabulary:
• Producers: organisms which produce their own food, also called
autotrophs. (Plants, Algae, Phytoplankton, etc)
• Consumers: organisms which obtain their food from other organisms,
also called heterotrophs. (Everything else!)
– Primary consumers consume producers.
– Secondary consumers consume other consumers
• Detritivores: feed on plant and animal remains and other dead
matter.
• Decomposers: organisms which break down dead and decaying
matter.
Energy Flows in One Direction
Heterotrophs eat the
autotrophs (consumers)
Sun or inorganic
compounds
Autotrophs (producers)
Heterotrophs eat other
heterotrophs (carnivores)
So, How much of the sun’s energy ends up in the food we eat?
How much energy is stored/ transferred?
10% Rule:
10% of energy at one
trophic level can be
used by consumers at
the next trophic level.
Trophic Level:
Each step in a feeding
relationship.
This means that 90%
is lost…
Where does all of
the energy go?!
In this example black dots represent energy units.
How much of the sun’s energy ends up in the food we eat?
Where does the “lost” energy go?
Energy is “lost” when paper burns.
Where does the energy go? How do you know?
What do these images show?
Table of Contents
How much of the sun’s energy ends up in the food we eat?
Which foods require the most energy to make?
What does this mean for humans as top-level consumers?
7
Join this friendly farmer for lunch to talk about how the sun's energy reaches your plate!
How much of the sun’s energy ends up in the food we eat?
"Three hundred trout are needed to support one man for a year.
The trout, in turn, must consume 90,000 frogs,
…that must consume 27 million grasshoppers
…that live off of 1,000 tons of grass."
What is the energy advantage to being a primary consumer
rather than a secondary consumer?
Which foods require the most energy to make?
What does this mean for humans as top-level consumers?
How can we display this data in a logical manner?
Displaying Data: Ecological Pyramids
• Represent relationships among trophic levels, each
reducing at higher and higher levels.
– Energy: amount of incoming energy.
– Biomass: mass of living tissue.
– Numbers: number of organisms.
What is Nutrient Cycling?
• Biogeochemical cycles: passage of matter
from one organism to another in the
biosphere.
• Nutrients are finite (not like the Sun which
supplies constant energy), so they must be
(re)cycled through various parts of nature.
– Relies heavily on Decomposers and movement
through the cycle (not getting “stuck” in one area)
• The Five (5) Major Biogeochemical Cycles:
– Carbon, Water, Nitrogen, Sulfur, Phosphorous.
• Carbon is the building
blocks of life.
– Definition of “Organic”
• CO2 = Carbon Dioxide
• Living things take in
Oxygen and give off CO2
through Aerobic or Cell
Respiration.
• Plants take in CO2 through
photosynthesis and
produce Oxygen.
• Organisms/Living things
contain the most carbon in
the Carbon cycle.
• As organisms die and enter
the soil, they eventually
become fuel over millions
of years (“fossil fuels.”)
• Natural Processes of
Volcanoes give off CO2
Cycles of Nature:
The Carbon Cycle
Where do we find carbon?
How Humans affect the
Carbon Cycle
• Greenhouse Gases
– Excess CO2 in the atmosphere acts as a trap for heat and water vapor.
• Global Warming
– Warming of the Earth causes ice caps to melt, causing the ocean to
change temperature and salinity, raising sea levels, changing climate
& weather.
• Deforestation and Habitat Destruction
– Without Trees to undergo photosynthesis to
convert CO2 to Oxygen, Carbon levels will
continue to rise.
- Removal of trees also harms biodiversity
(the amount of different organisms) and
habitats for organisms.
Cycles of Nature:
The Water Cycle
• Evaporation – Water taken into the
atmosphere
• Transpiration – Plants losing water
through leaves
• Precipitation – Water that falls from
the atmosphere (rain, snow, hail,
etc)
• Runoff – Water that enters the
ocean
• Groundwater – Water that is
absorbed into the ground
• Water vapor is also given off by
volcanic eruptions.
• The Water Cycle helps cool the
Earth preventing large changes in
Global Temperatures.
How Humans affect the
Water Cycle
• Human Use of Water:
– Agriculture
– Dams and Deforestation
– Urbanization (Living in Cities)
– Overuse of Aquifers
• Saltwater Intrusion (ocean)
• Subsidence (lead to collapse)
• Clean Water supply
– 1 billion people (16%) do
not have any access to clean water.
– Can cause outbreaks of disease
• Examples: cholera, hepatitis, mosquito breeding, etc.
• Acid Rain (in combination with Nx and Sx)
– Hurts plants, animals and buildings
Cycles of Nature:
The Nitrogen Cycle
• 78% of the air is Nitrogen
• Plants use nitrogen in their
cellular processes
• Nitrogen is present in our DNA
and RNA and in
amino acids (proteins).
• The food chain largely moves
Nitrogen around.
• Bacteria and Lightning takes
Nitrogen gas and puts into a
useable form (called Nitrogen
Fixation)
• Bacteria have a mutualisitic
relationship with plants and live
on their roots.
How Humans affect the Nitrogen Cycle
• Humans contribute extra Nitrogen in the cycle due
to fertilizers and animal waste (hog lagoons) that
runoff into in the lakes and rivers.
• Extra Nitrogen in the groundwater can interfere
with blood/oxygen levels and cause blue-baby
syndrome.
• Excess Nitrogen can cause Eutrophication which
causes aquatic life to die due to…
– the low levels of oxygen (fish kills)
– extra algae to grow (algal bloom.)
• High levels of ammonia is also toxic to animals.
Cycles of Nature: Sulfur Cycle
• important part of amino acids/proteins and plays role
in forming shape of molecules
• most sulfur is trapped in rocks and is broken down then
taken up by plants
– organisms eat the plants and take up S
– organisms release S into the atmosphere through
decomposition as Hydrogen Sulfide (H2S)
Human Impacts on the Sulfur Cycle:
• Hydrogen sulfide combines with oxygen to form H2SO4,
sulfuric acid; falls to the earth as acid rain.
• The burning of fossil fuels release SO2; combines with
atmospheric H2O and O2 to form acid rain.
Cycles of Nature: Phosphorus Cycle
• Phosphorus is found in bones,
teeth, DNA, and ATP (energystoring molecule)
• Naturally, phosphorus is found in
rocks as calcium phosphate
(Ca3(PO4)2)
• As the rocks break down,
phosphate is released into the
soil where it is taken up by
plants.
•Human Impacts on the Phosphorus Cycle:
• The phosphate is obtained through mining of certain deposits of calcium
phosphate called apatite. Huge quantities of sulfuric acid are used in the
conversion of the phosphate rock into a fertilizer products.
• Run off is a major concern as animal waste fertilizer may collect in lakes.
• Human sewage also causes problems as Phosphorus is only removed if
there are tertiary treatments involved.
Recap!
• Remember, Energy Flows as Nutrients Cycle!