chapter 3 ecosystems and energy - napa valley college ecology “eco” house & “logy” study...
TRANSCRIPT
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 “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.
Ecology Definitions Species
A group of similar organisms whose members freely interbreed
Population A group of organisms of the same species that occupy 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
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
Energy The ability or capacity to do work Chemical, Thermal, Mechanical, Nuclear,
Electrical, and Radiant/Solar
Energy
Energy exists as: Potential energy
(stored energy) Kinetic energy (energy
of motion)
Potential energy is converted to kinetic energy as arrow is released
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)
Photosynthesis
Biological process by which energy from the sun (radiant energy) is transformed into chemical energy of sugar molecules
6 CO2 + 12 H2O + radiant energy
C6H12O6 + 6 H2O + 6 O2
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
C6H12O6 + 6 O2 + 6 H2O
6 CO2 + 12 H2O + energy
Energy Flow
Passage of energy through an ecosystem Producers Primary consumers Secondary consumers Decomposers
Food Chains - The Path of Energy Flow
Energy from food passes from one organisms to another based on their Trophic Level An organisms position in a food chain 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
Ecological Pyramids
Graphically represent the relative energy value of each trophic level Large amounts of energy are lost between trophic
levels to heat
Three main types Pyramid of numbers Pyramid of biomass Pyramid of energy
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
Pyramid of Biomass
Illustrates the total biomass at each successive trophic level Biomass: measure
of the total amount of living material
Progressive
reduction in biomass through trophic levels
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
Ecosystem Productivity
Gross Primary Productivity (GPP) Total amount of energy that plants capture and
assimilate in a given period of time