Energy
Energy: the capacity to do work or transfer heat
Types:
• Kinetic energy – energy of motion. e.g., a moving
automobile,
• Potential energy – stored energy. e.g., a stretched
rubber band, water stored behind a dam.
http://www.youtube.com/watch?v=iX8PRv_Mj18
Video: Electromagnetic Spectrum
Electromagnetic Radiation
The wavelength varies ________________ to both
frequency and energy.
__________ wavelengths have a higher frequency
and greater energy content than longer wavelengths.
Increasing Frequency and Increasing Energy
Increasing Wavelength
Energy Quality
Energy quality is a
measure of how
useful an energy
source is.
High-quality energy is
________________
_________________.
Low-quality energy is
________________
_________________
Example:_________
Energy Laws
First Law of Thermodynamics: energy is neither
created nor destroyed, but may be converted
from one form to another.
(AKA: Law of Conservation of Energy)
•also stated, "you can't get something for
nothing", in terms of energy quantity.
Energy Laws
Second Law of Thermodynamics: when energy is
converted from one form to another, some of the
useful energy is always ________________________
____________________________.
Also can be stated: entropy increases.
• entropy is a measure of __________;
• increased entropy means increased randomness
or dispersion;
• degraded energy generally in form of heat;
Discuss with your table partner:
The flow of energy through a food chain forms an energy
pyramid, with less available energy with each trophic
level (step in the food chain).
o
o
o
o
How is this consistent with the First Law of TD?
What happens to the total energy?
What happens to the entropy?
What happens to the overall energy quality?
Ecological efficiency: The percentage of usable energy
transferred from one trophic level to the next.
What is the ecological efficiency for each step the food
chain shown below?
______________
The ecological efficiency can range from 2% to 40%,
with 10% being the typical ecological efficiency.
Prokaryotic and Eukaryotic Cells
Prokaryotic cells: Have no membrane-bound
organelles. Bacteria are composed of prokaryotic cell
Eukaryotic cells: More highly organized cells,
containing membrane-bound organelles that each
perform a specific function.
Biosphere
Parts of the earth's air, water, and
soil where life is found
Ecosystem
A community of different species
interacting with one another and with their
nonliving environment of matter and energy
Community
Populations of different species living in a
particular place, and potentially interacting
with each other
Population
A group of individuals of the same species
living in a particular place
Organism
Cell
Molecule
Atom
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
Smallest unit of a chemical element that
exhibits its chemical properties
Ecosystems Have Living and
Nonliving Components
 Abiotic
Nonliving components
–
–
–
–
–
–
Water
Air
Nutrients
Rocks
Heat
Solar energy
 Biotic
Living and ___________ (Example: Leaf litter is biotic)
Range of Tolerance for a
Population
of Organisms
INSERT FIGURE 3-10 HERE
Several Abiotic Factors Can Limit
Population Growth
Limiting factor principle
– Too much or too little of any abiotic factor can
limit or prevent growth of a population, even if all
other factors are at or near the optimal range of
tolerance
Living Components of Ecosystems
First Trophic
Level
Second Trophic
Level
Third Trophic
Level
Fourth Trophic
Level
Producers
(plants)
Primary
consumers
(herbivores)
Secondary
consumers
(carnivores)
Tertiary
consumers
(top carnivores)
Heat
Heat
Heat
Heat
Solar
energy
Heat
Heat
Heat
Decomposers and detritus feeders
Trophic Level: A step in a food chain
_________ flow of energy in an ecosystem.
Living Components of Ecosystems
 Autotrophs / Producers
– Photosynthesis
– Chemosynthesis
 Heterotrophs / Consumers
- Generally not more than three or four levels of
consumers due to the energy pyramid
Photosynthesis vs. Chemosynthesis
Photosynthesis
o Uses sunlight to provide the
energy required to produce
carbohydrates from carbon
dioxide and water.
6 CO2 + 6 H2O C6H12O6 + 6 O2
Chemosynthesis
o Uses the energy from certain
compounds such as hydrogen
sulfide from volcanic vents to
provide the energy to produce
carbohydrates.
o Performed by certain
prokaryotic organisms.
o Occurs at ______________
_______________________.
Video: Chemosynthesis
http://www.youtube.com/watch?v=BXGF3XS-yAI
Releasing Stored Energy
All organisms store energy in sugars and other organic
molecules.
This energy is released as needed through either:
-aerobic respiration (with oxygen)
C6H12O6 + 6 O2  6 CO2 + 6 H2O
- anaerobic respiration also known as
fermentation (without oxygen)
Plants perform both photosynthesis
and aerobic respiration.
Gross Primary Productivity (GPP)
Gross Primary Productivity is the rate at which producers
convert solar energy (for almost all producers) into
chemical energy.
Usually measured in a unit of energy per unit of area over
a given time span.
Example : kcal/m2/year
Some of the gross primary productivity is needed to
________________________ and is not passed along
the food chain.
Net Primary Productivity
Net Primary Productivity is the amount of chemical
energy available ____________________________
_________________________________________.
Discuss with your table partner:
What could you measure to determine the NPP of an
ecosystem? (Hint: Productivity = rate of photosynthesis)
By measuring the increase ______________________
__________________________or the decrease _______
___________________
Estuaries and swamps generally have a high net primary
productivity. Why?
______________________________________________
______________________________________________
Why is the NPP compared for different ecosystems
rather than the GPP?
NPP can be measured by ______________________ .
GPP ________________________________________.
Estimated Annual Average NPP in
Major Life Zones and Ecosystems
Detritivores and Decomposers
Detritivores consume dead organisms.
Decomposers secrete enzymes to break down dead
organisms. Recycle nutrients into the surrounding area.
_________of Nutrients in an Ecosystem
Water Cycle Processes
evaporation: conversion from liquid to vapor form
transpiration: __________________________
condensation: conversion of vapor to liquid droplets
precipitation: movement as rain, sleet, hail, & snow
infiltration: movement into soil
percolation:________________________________
runoff: surface flow downslope to ocean.
Role of Carbon?
Building block of organic molecules
(carbohydrates, fats, proteins, & nucleic acid)
– essential to life
Currency of energy exchange – chemical
energy for life stored as bonds in organic
compounds
Carbon dioxide (CO2) greenhouse gas – traps
heat near Earth's surface & plays a key role
as "nature's thermostat”
Carbon Cycle Processes
Photosynthesis (= carbon fixation) moves C from
atmosphere to organic molecules (C,H,O
compounds) in organisms
Movement through food web: C movement in
organic form from organism to organism
Aerobic respiration: organic molecules broken
down to release CO2 back to atmosphere
Combustion: organic molecules broken by burning
down to release CO2 back to atmosphere
Review with your table partner:
What are two ways that humans are shifting the
carbon cycle to increase the amount of carbon
found in the atmosphere (CO2) rather than
stored in organic (carbon-containing)
molecules?
_______________________________________
_______________________________________
_______________________________________
_______________________________________
Nitrogen Cycle
Nitrogen is needed by all living things.
• N is part of ____________________________________
• Nitrogen (N2) is the most common gas in the
atmosphere (78%).
• However, most organisms can not utilize N2.
( ____________________________________________________.)
Nitrogen fixation: conversion of N2 (nitrogen gas)
to NH4+ (ammonium) a form usable by plants,
• Biological by bacteria & blue-green algae
(anaerobic),
e.g. Rhizobium found in soil and in ________
_______________________;
• Atmospheric by lightning,
Nitrification: conversion of NH4+ to NO2- (nitrite) to
NO3-(nitrate) by microbes;
Uptake by plants, forms proteins and other N
containing organic compounds, enters food chain;
Nitrogen Cycle Processes Cont.
• Ammonification: returned to NH4+
inorganic forms by saprophytes and
decomposers;
• Denitrification: conversion of NH4+ to N2 by
combustion or microbes. Conversion of
NOx to N2 by bacteria
Video: Nitrogen Cycle
http://www.youtube.com/watch?v=4NKGS4bj7cc
First half covers Haber-Bosch Process.
http://www.youtube.com/watch?v=tdEE5uvFhOM
Video: The Haber Process
Inorganic Fertilizers
During WWI, Fritz Haber developed process
to convert atmospheric nitrogen into
ammonia to make inorganic nitrate
fertilizers.
____________________________
____________________________
Revolutionized farming:
increasing yields. Part of the
GREEN REVOLUTION
It is estimated that perhaps 20% of world’s
population is alive due to increased food
production caused by this technology.
P
H
O
S
P
O
R
O
U
S
C
Y
C
L
E
• Released from _______________________
• No atmospheric component of cycle
• Needed by all living things for:
DNA , ATP, Phospholipids