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Ecosystems and Energy. 3. Overview of Chapter 3. What is Ecology? The Energy of Life Laws of Thermodynamics Photosynthesis and Cellular Respiration Flow of Energy Through Ecosystems Producers, Consumers & Decomposers Ecological Pyramid Ecosystem Productivity. Ecology. Ecology - PowerPoint PPT Presentation
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© 2012 John Wiley & Sons, Inc. All rights reserved.
Overview of Chapter 3
What is Ecology? The Energy of Life
Laws of Thermodynamics Photosynthesis and Cellular Respiration
Flow of Energy Through Ecosystems Producers, Consumers & Decomposers Ecological Pyramid Ecosystem Productivity
© 2012 John Wiley & Sons, Inc. All rights reserved.
Ecology
Ecology “eco” house & “logy” study of The study of interactions among and between
organisms in their abiotic environment Biotic - living environment
Includes all organisms Abiotic - non living or physical environment
Includes living space, sunlight, soil, precipitation, etc.
© 2012 John Wiley & Sons, Inc. All rights reserved.
Ecology
Ecologists are interested in the levels of life above that of organism
© 2012 John Wiley & Sons, Inc. All rights reserved.
Ecology Definitions
Species - A group of similar organisms whose members freely interbreed
Population - A group of organisms of the same species that occupy that live in the same area at the same time
Community - All the populations of different species that live and interact in the same area at the same time
Ecosystem - A community and its physical (abiotic) environment
Landscape - Several interacting ecosystems
© 2012 John Wiley & Sons, Inc. All rights reserved.
Ecology
Biosphere contains earth’s communities, ecosystems and landscapes, and includes: Atmosphere-
gaseous envelope surrounding earth
Hydrosphere- earth’s supply of water
Lithosphere- soil and rock of the earth’s crust
© 2012 John Wiley & Sons, Inc. All rights reserved.
Energy
The ability or capacity to do work Chemical, Thermal, Mechanical, Nuclear,
Electrical, and Radiant/Solar (below)
© 2012 John Wiley & Sons, Inc. All rights reserved.
Energy
Energy exists as: Potential energy
(stored energy) Kinetic energy
(energy of motion)
Potential energy is converted to kinetic energy as arrow is released from bow
© 2012 John Wiley & Sons, Inc. All rights reserved.
Thermodynamics
Study of energy and its transformations System- the object being studied
Closed System- Does not exchange energy with surroundings (rare in nature)
Open System- exchanges energy with surroundings
© 2012 John Wiley & Sons, Inc. All rights reserved.
Laws of Thermodynamics
First Law of Thermodynamics Energy cannot be created or destroyed; it can
change from one form to another
Second Law of Thermodynamics When energy is converted form one form to
another, some of it is degraded to heat Heat is highly entropic (disorganized)
© 2012 John Wiley & Sons, Inc. All rights reserved.
Photosynthesis
Biological process by which energy from the sun (radiant energy) is transformed into chemical energy of sugar molecules
6 CO6 CO2 2 + 12 H+ 12 H22O + radiant energyO + radiant energy
CC66HH1212OO66 + 6 H + 6 H22O + 6 OO + 6 O22
© 2012 John Wiley & Sons, Inc. All rights reserved.
Cellular Respiration
The process where the chemical energy captured in photosynthesis is released within cells of plants and animals
This energy is then used for biological work
CC66HH1212OO66 + 6 + 6 OO2 2 + 6 H+ 6 H22OO
6 CO6 CO22 + 12 H + 12 H22O + energyO + energy
© 2012 John Wiley & Sons, Inc. All rights reserved.
Energy Flow Through Ecosystems
Passage of energy through an ecosystem
© 2012 John Wiley & Sons, Inc. All rights reserved.
Food Chains- The Path of Energy Flow
Energy from food passes from one organisms to another based on their Trophic Level Def: An organism’s position in a food chain, which
is determined by its feeding relationships First Trophic Level: Producers Second Trophic Level: Primary Consumers Third Tophic Level: Secondary Consumers Decomposers are present at all trophic levels
© 2012 John Wiley & Sons, Inc. All rights reserved.
Ecological Pyramids
Graphically represent the relative energy value of each trophic level Important feature is that large amount of energy
are lost between trophic levels to heat Three main types
Pyramid of numbers Pyramid of biomass Pyramid of energy
© 2012 John Wiley & Sons, Inc. All rights reserved.
Pyramid of Numbers
Illustrates the number of organisms at each trophic level Fewer organisms
occupy each successive level
Does not indicate: biomass of organisms
at each level amount of energy
transferred between levels
© 2012 John Wiley & Sons, Inc. All rights reserved.
Pyramid of Biomass
Illustrates the total biomass at each successive trophic level
Biomass: measure of the total amt of living material
90% reduction in biomass through trophic levels
© 2012 John Wiley & Sons, Inc. All rights reserved.
Pyramid of Energy
Illustrates how much energy is present at each trophic level and how much is transferred to the next level
Most energy dissipates between trophic levels
Explains why there are so few trophic levels
© 2012 John Wiley & Sons, Inc. All rights reserved.
Ecosystem Productivity
Gross Primary Productivity (GPP) Total amount of energy that plants capture and
assimilate in a given period of time Net Primary Productivity (NPP)
Plant growth per unit area per time Represents the rate at which organic material is
actually incorporated into the plant tissue for growth
GPP – cellular respiration = NPP Only NPP is available as food to organisms