Chapter 3 Ecosystems and Energy - dsapresents.orgdsapresents.org/staff/john-jackson/files/2019/09/CH3.pdf · Overview of Chapter 3 ! What is Ecology? ! The Energy of Life ! Laws of

Chapter 3 Ecosystems and Energy

© 2015 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 and Decomposers ¤ Path of Energy Flow: Who Eats Whom ¤ Ecological Pyramids ¤ Ecosystem Productivity


Ecology

¨  Ecology


Ecology

¨  Ecology ¤  “logy” study of, “eco” house – study of one’s house


Ecology

¨  Ecology ¤  “logy” study of, “eco” house – study of one’s house ¤ The study of interactions among and between

organisms and their abiotic environment


Ecology


organisms and their abiotic environment ¨  Biotic - living environment

¤  Includes all organisms


Ecology


organisms and 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 to produce fertile offspring


Ecology Definitions


¨  Population - A group of organisms of the same species that live in the same area at the same time


Ecology Definitions



¨  Community - All the populations of different species that live and interact in the same area at the same time


Ecology Definitions




¨  Ecosystem - A community and its physical (abiotic) environment


Ecology Definitions




¨  Ecosystem - A community and its physical (abiotic) environment

¨  Landscape - Several interacting ecosystems


Ecology ¨  Biosphere contains earth’s communities,

ecosystems and landscapes, and includes:



ecosystems and landscapes, and includes: §  Atmosphere-

gaseous envelope surrounding earth





§  Hydrosphere- earth’s supply of water





§  Hydrosphere- earth’s supply of water

§  Lithosphere- soil and rock of the earth’s crust


Energy of Life

¨  The ability or capacity to do work ¨  Chemical, Thermal, Mechanical, Nuclear,

Electrical, and Radiant/Solar (below)


¨  Solar radiation is the primary source of energy on planet

Energy of Life

Plants turn solar radiation into food


Energy of Life

¨  Energy exists as:


Energy of Life

¨  Energy exists as: ¤ Potential energy

(stored energy)


Energy of Life

¨  Energy exists as: ¤ Potential energy

(stored energy) ¤ Kinetic energy

(energy of motion)


Thermodynamics

¨  Study of energy and its transformations


Thermodynamics

¨  Study of energy and its transformations ¨  System- the object being studied


Thermodynamics


§  Closed System- Does not exchange energy with surroundings (rare in nature)


Thermodynamics


§  Closed System- Does not exchange energy with surroundings (rare in nature)

§  Open System- exchanges energy with surroundings


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



¨  Second Law of Thermodynamics ¤ When energy is converted form one form to

another, some of it is lost as heat









§  Engine converts chemical energy of gasoline into mechanical energy inefficiently


Photosynthesis


Photosynthesis

¨  Biological process by which energy from the sun (radiant energy) is transformed into chemical energy of carbohydrate (sugar) molecules


Photosynthesis

¨  Biological process by which energy from the sun (radiant energy) is transformed into chemical energy of carbohydrate (sugar) molecules

6 CO2 + 12 H2O + radiant energy

C6H12O6 + 6 H2O + 6 O2

Chlorophyll in plants


Cellular Respiration



¨  The process where the chemical energy captured in photosynthesis is released within cells of plants and animals




C6H12O6 + 6 O2 + 6 H2O

6 CO2 + 12 H2O + energy




¨  This energy is then used for biological work

C6H12O6 + 6 O2 + 6 H2O

6 CO2 + 12 H2O + energy


Photosynthesis and Cellular Respiration


Life without Sun

¨  1970s – discovered hydrothermal vents in deep ocean (200oC or 392oF)


Life without Sun


¨  Rich ecosystem supported without light


Life without Sun


¨  Rich ecosystem supported without light ¨  Bacteria perform

chemosynthesis


Life without Sun


¨  Rich ecosystem supported without light ¨  Bacteria perform

chemosynthesis ¤ Similar to

photosynthesis, but use chemical (H2S) not sunlight


Energy Flow Through Ecosystems

¨  Passage of energy through an ecosystem


Food Chains- The Path of Energy Flow



¨  Energy from food passes from one organism to another based on their Trophic Level



¨  Energy from food passes from one organism to another based on their Trophic Level ¤ Definition: An organism’s position in a food chain,

which is determined by its feeding relationships




which is determined by its feeding relationships ¨  First Trophic Level: Producers




which is determined by its feeding relationships ¨  First Trophic Level: Producers ¨  Second Trophic Level: Primary Consumers




which is determined by its feeding relationships ¨  First Trophic Level: Producers ¨  Second Trophic Level: Primary Consumers ¨  Third Trophic Level: Secondary Consumers




which is determined by its feeding relationships ¨  First Trophic Level: Producers ¨  Second Trophic Level: Primary Consumers ¨  Third Trophic Level: Secondary Consumers ¨  Decomposers are present at all trophic levels


Food chains


Food chains

¨  Autotrophs =


Food chains

¨  Autotrophs = Producers


Food chains

¨  Autotrophs = Producers ¤ Auto “self” and tropho “nourishment”


Food chains

¨  Autotrophs = Producers ¤ Auto “self” and tropho “nourishment” ¤ Produce own food from inorganic material


Food chains

¨  Autotrophs = Producers ¤ Auto “self” and tropho “nourishment” ¤ Produce own food from inorganic material ¤ Ex: plants via photosynthesis and hydrothermal

vent bacteria via chemosynthesis


Food chains


Food chains

¨  Heterotrophs =


Food chains

¨  Heterotrophs = Consumers


Food chains

¨  Heterotrophs = Consumers ¤ heter “different” and tropho “nourishment”


Food chains

¨  Heterotrophs = Consumers ¤ heter “different” and tropho “nourishment” ¤ Uses bodies of other organisms as food


Food chains

¨  Heterotrophs = Consumers ¤ heter “different” and tropho “nourishment” ¤ Uses bodies of other organisms as food

¨  Omnivores – eat both plants and animals


Food chains

¨  Consumers of detritus (detritivores) ¤ Eat dead material such as leaves, carcasses,

feces ¤ Ex: crabs, worms, millipedes, snails


Food chains

¨  Decomposers ¤ Breakdown dead organic material ¤ Release inorganic molecules (CO2 and nutrients)

that producers can use

¤ Ex: fungus,

bacteria ¤  Involved in

all aspects of food chains


Food Web


Food Web

¨  Food web visualizes feeding relationships within a community


Food Web

¨  Food web visualizes feeding relationships within a community ¤ More complex

than food chain


Ecological Pyramids


Ecological Pyramids

¨  Graphically represent the relative energy value of each trophic level


Ecological Pyramids

¨  Graphically represent the relative energy value of each trophic level ¤  Important feature - large amount of energy is lost

as heat between trophic levels


Ecological Pyramids


as heat between trophic levels ¨  Three main types


Ecological Pyramids



¤ Pyramid of numbers


Ecological Pyramids



¤ Pyramid of numbers ¤ Pyramid of biomass


Ecological Pyramids



¤ Pyramid of numbers ¤ Pyramid of biomass ¤ Pyramid of energy


Pyramid of Numbers


Pyramid of Numbers

¨  Illustrates the number of organisms at each trophic level


Pyramid of Numbers

¨  Illustrates the number of organisms at each trophic level §  Fewer organisms

occupy each successive level


Pyramid of Numbers




Pyramid of Numbers




Pyramid of Numbers




Pyramid of Biomass


Pyramid of Biomass

¨  Illustrates the total biomass at each successive trophic level


Pyramid of Biomass


q Biomass: measure of the total amount of living material


Pyramid of Biomass


q Biomass: measure of the total amount of living material

q  ~90% reduction in biomass through trophic levels


Pyramid of Energy


Pyramid of Energy

¨  Illustrates how much energy is present at each trophic level and how much is transferred to the next level


Pyramid of Energy


¨  Most energy dissipates between trophic levels


Pyramid of Energy


¨  Most energy dissipates between trophic levels ¤ Lost as heat and energy

to maintain each level


Ecosystem Productivity



¨  Gross Primary Productivity (GPP)



¨  Gross Primary Productivity (GPP) ¤ Total amount of energy that plants capture and

assimilate in a given period of time




assimilate in a given period of time ¨  Cellular respiration (R)

¤ Plants use some energy of GPP to maintain themselves

¤ Plants respire too






¤ Plants respire too ¨  Net Primary Productivity (NPP)






¤ Plants respire too ¨  Net Primary Productivity (NPP)

¤ Productivity after respiration losses are subtracted ¤ What is available as food for other organisms





¨  GPP is similar to gross pay in paycheck



¨  GPP is similar to gross pay in paycheck ¨  R is similar to taxes



¨  GPP is similar to gross pay in paycheck ¨  R is similar to taxes ¨  NPP is similar to take home pay



¨  GPP is similar to gross pay in paycheck ¨  R is similar to taxes ¨  NPP is similar to take home pay

Net Primary Productivity

(plant growth per area per time)

Gross Primary Productivity (total photosynthesis per

area per time)

Plant Cellular Respiration

(per area per time) = -

Documents

Chapter 3 Ecosystems and Energy - dsapresents.orgdsapresents.org/staff/john-jackson/files/2019/09/CH3.pdf · Overview of Chapter 3 ! What is Ecology? ! The Energy of Life ! Laws of