Chapter 3Chapter 3Ecosystems and Ecosystems and EnergyEnergy

Chesapeake Bay Salt Marsh Ecosystem Chesapeake is an

estuary (affected by tides)

Tidal marshes are special because they: Purify water Protect the coastline Provide shelter and

breeding grounds for aquatic species

Are one of the most productive ecosystems in terms of energy!

Chesapeake Ecosystem Water is salty on the ocean

side, brackish in the middle, and fresh water at the head of the bay

Base of the food web is cordgrass (shown in photo). This has an advantage since it can grow under saline conditions and periodic submergence due to tides.

The bay receives high nutrient levels (N,P) from treated human sewage and farm runoff, which promotes algal growth (cordgrass too), which serve as food for other organisms.

What is the Chesapeake like?What is the Chesapeake like?

Major kinds of life in the salt marsh ecosystem:Major kinds of life in the salt marsh ecosystem:1.1. InsectsInsects

Millions of mosquitoes and horsefliesMillions of mosquitoes and horseflies2.2. BirdsBirds

Sparrows, hulls, clapper railsSparrows, hulls, clapper rails3.3. Shrimp, lobster, crabs, barnacles, worms, clams and snails Shrimp, lobster, crabs, barnacles, worms, clams and snails

are all present and seek refuge in the cordgrass.are all present and seek refuge in the cordgrass. No amphibians live there (salt) but the terrapin turtle No amphibians live there (salt) but the terrapin turtle

does.does.4.4. Numerous species of fish call the Chesapeake home…Numerous species of fish call the Chesapeake home…

including:including: Sea trout, croaker, bluefish, striped bassSea trout, croaker, bluefish, striped bass Young species enter from the ocean.Young species enter from the ocean.

5.5. Meadow voles live along the shores, and are excellent Meadow voles live along the shores, and are excellent swimmers too….and they eat leaves, stems and many swimmers too….and they eat leaves, stems and many insectsinsects

What does the Chesapeake Tell Us? This ecosystem is interdependent upon human

inputs (pollutants such as nitrates, phosphates and others like oil, gas, etc.) and also it’s natural setting.

It remains one of the most productive ecosystems on the planet…but it is in peril!

Too much pollution…overfishing…too many nutrients (eutrophication)…oil spills….growing population….

It is important to protect our most productive ecosystems!

Chesapeake EcosystemChesapeake Ecosystem Chesapeake also serves as an excellent Chesapeake also serves as an excellent

case study in how energy flows through case study in how energy flows through an ecosystem!an ecosystem!

Overview of Chapter 3Overview of Chapter 3

What is Ecology?What is Ecology? The Energy of LifeThe Energy of Life

Laws of ThermodynamicsLaws of Thermodynamics Photosynthesis and Cellular RespirationPhotosynthesis and Cellular Respiration

Flow of Energy Through EcosystemsFlow of Energy Through Ecosystems Producers, Consumers & DecomposersProducers, Consumers & Decomposers Ecological PyramidEcological Pyramid Ecosystem ProductivityEcosystem Productivity

EcologyEcology

EcologyEcology ““eco” house & “logy” study ofeco” house & “logy” study of The study of interactions among and The study of interactions among and

between organisms in their abiotic between organisms in their abiotic environmentenvironment

Biotic - living environmentBiotic - living environment Includes all organismsIncludes all organisms

Abiotic - non living or physical Abiotic - non living or physical environmentenvironment Includes living space, sunlight, soil, Includes living space, sunlight, soil,

precipitation, etc.precipitation, etc.

EcologyEcology

Ecologists Ecologists are are interested in interested in the levels of the levels of life above life above that of that of organismorganism

Ecology DefinitionsEcology Definitions SpeciesSpecies

A group of similar organisms whose members freely A group of similar organisms whose members freely interbreedinterbreed

PopulationPopulation A group of organisms of the same species that A group of organisms of the same species that

occupy that live in the same area at the same timeoccupy that live in the same area at the same time CommunityCommunity

Al the populations of different species that live and Al the populations of different species that live and interact in the same area at the same timeinteract in the same area at the same time

EcosystemEcosystem A community and its physical (abiotic) environmentA community and its physical (abiotic) environment

LandscapeLandscape Several interacting ecosystemsSeveral interacting ecosystems

EcologyEcology

Biosphere contains earth’s communities, Biosphere contains earth’s communities, ecosystems and landscapes, and includes:ecosystems and landscapes, and includes: AtmosphereAtmosphere - -

gaseous gaseous envelope envelope surrounding surrounding earthearth

HydrosphereHydrosphere - - earth’s supply of earth’s supply of waterwater

LithosphereLithosphere - soil - soil and rock of the and rock of the earth’s crustearth’s crust

The First & Second Law of The First & Second Law of ThermodynamicsThermodynamics

By: Michelle ZiccaBy: Michelle Zicca

Basic Laws of Basic Laws of ThermodynamicsThermodynamics

First Law of ThermodynamicsFirst Law of Thermodynamics– energy can neither be created nor energy can neither be created nor

destroyeddestroyed Second Law of Second Law of

ThermodynamicsThermodynamics– naturally occurring processes are naturally occurring processes are

directionaldirectional

First Law of First Law of ThermodynamicsThermodynamics One form of work may be One form of work may be

converted into another,converted into another, or, work may be converted to or, work may be converted to

heat,heat, or, heat may be converted to or, heat may be converted to

work,work, but, final energy = initial energybut, final energy = initial energy

22ndnd Law of Law of ThermodynamicsThermodynamics We intuitively know that heat flows We intuitively know that heat flows

from higher to lower temperatures from higher to lower temperatures and and notnot the other direction. the other direction.– i.e., heat flows “downhill” just like i.e., heat flows “downhill” just like

waterwater– You You cannotcannot raise the temperature in raise the temperature in

this room by adding ice cubes.this room by adding ice cubes. Thus processes that employ heat Thus processes that employ heat

are inherently irreversible.are inherently irreversible.

Heat/Work Heat/Work ConversionsConversions Heat transfer is inherently Heat transfer is inherently

irreversible. This places limits on the irreversible. This places limits on the amount of work that can be amount of work that can be produced from heat.produced from heat.

Heat can be converted to work using Heat can be converted to work using heat enginesheat engines– Jet engines (planes), steam engines Jet engines (planes), steam engines

(trains), internal combustion engines (trains), internal combustion engines (automobiles)(automobiles)

Open & Closed Open & Closed SystemsSystems Open system exchanges energy Open system exchanges energy

with its surroundingswith its surroundings A closed system is self-contained A closed system is self-contained

and isolated; does not exchange and isolated; does not exchange energy with its surroundings.energy with its surroundings.

Where did the energy Where did the energy go?go?

By the First Law of By the First Law of Thermodynamics, the energy we Thermodynamics, the energy we put into the water (either work or put into the water (either work or heat) cannot be destroyed.heat) cannot be destroyed.

The heat or work added increased The heat or work added increased the internal energy of the water.the internal energy of the water.

Processes that take Processes that take PlacePlace

Reversible Processes

A reversible process is a quasi-equilibrium, or quasi-static, process with a more restrictive requirement.

Internally reversible process

The internally reversible process is a quasi-equilibrium process, which, once having taken place, can be reversed and in so doing leave no change in the system. This says nothing about what happens to the surroundings about the system.

Totally or externally reversible process

The externally reversible process is a quasi-equilibrium process, which, once having taken place, can be reversed and in so doing leave no change in the system or surroundings.

Overview of Overview of ThermodynamicsThermodynamics Two constraints on life processes– Evolutionary history– Physics and chemistry• Living things must play by these

rules• Order is sustained in living things at

theexpense of energy and disorder to the

surroundings

Pictures and ExamplesPictures and Examples

27

Three Types of ProcessThree Types of Process

AdiabatAdiabat

IsothermIsotherm

PP

VVHeat bath or reservoirHeat bath or reservoir

Isothermal processIsothermal process Adiabatic processAdiabatic process

Adiabatic free expansionAdiabatic free expansion PP

VV

●●11

●●22

End pointsEnd points

SystemSystem

Photosynthesis, Cellular Respiration, and Chemosynthesis

By Wesley Washington

Photosynthesis

• It is a biological process where plants such as algae, and some bacteria take in light energy and change it into carbohydrates (sugar).

• Glucose is the molecule that is formed by photosynthesis. Glucose is the fuel source of plants.

Photosynthesis

The carbon dioxide(6CO2) and water(12H2O) is synthesized with sunlight to form glucose(C6H12O6).

Left over products include water which is stored and Oxygen which is released.

Aerobic Cellular Respiration • Is essentially is the process of the cells

using energy to biological work.

• All organisms need to respire. Plants use glucose energy while most animals breathe.

• This process usually needs oxygen, however anaerobic bacteria hat lives in waterlogged soil, animal intestines (like yours!) and hydrothermal vents still respire without oxygen.

Chemosynthesis

• Happens at hydrothermal vents on the bottom of the sea floor.

• Bacteria living there is able to with stand temperatures of 392 F

• The vents spew out mineral rich water and toxic hydrogen sulfide.

Chemosynthesis

• The bacteria takes the raw inorganic chemicals and process them into food of the bacteria.

• Organisms such as the giant red tube worms have a symbiotic relationship with the bacteria allowing them to live inside their bodies in exchange for the energy they produce.

Producers, Consumers, and Decomposers

by: Joey Harkins• All organisms are classified as either a

producer, consumer, or decomposer• The basis of the classification is on how each

organism receives its nourishment

Producers• Producers (autotrophs)-

organisms that manufacture complex organic molecules from simple inorganic substances, such as CO2 and water, and using the energy from the sun .

• For example photosynthetic organisms

• Producers incorporate the chemicals they manufacture into their own bodies, becoming food sources for other animals.

Consumers• Consumers (heterophs)- use the bodies of

other organisms as a source of food energy and bodybuilding materials.

• Four types of consumers: primary consumers- herbivores, only eat producers secondary consumers- eat primary consumers tertiary consumers- eat secondary consumers detritus feeders- consume organic matter, like

animal carcasses, leaf litter, and feces

Decomposers• Decomposers (saprotrophs)-

heterotrophs that break down dead organic material and use the decomposition products to supply themselves with energy.

• Decomposers release inorganic molecules, such as CO2 and mineral salts, that producers can reuse.

• Bacteria and fungi are some examples of decomposers

• Producers, consumers, and decomposers all play an important role in the ecosystem.

• Producers provide food and oxygen for the community

• Consumers maintain a balance between producers and decomposers.

• Decomposers keep dead organisms and waste products to a minimum, while also releasing the potassium, nitrogen, and phosphorus from dead organisms.

The Path of Energy:The Path of Energy:Who Eats Whom in Who Eats Whom in

Ecosystems?Ecosystems?

Hunter LongenbergerHunter Longenberger

In an EcosystemIn an Ecosystem• Energy passes from

one organism to the next through a food chain

• Many interconnected food chain forms a food web

• Within each food chain there are trophic levels

Food chain

(just one path of energy)

Food web

(everything is connected)

Food WebFood Web

Trophic levelsTrophic levelsIs where the organism stands in the food webThis is based on the number energy transfer steps to that level

Tropic levels1. Producers (organisms that photosynthesize)2. Primary consumers (herbivores)3. Secondary consumers (carnivores)

At every step in the food chain there are decomposers

Trophic levelsTrophic levelsSecondary consumers

Primary consumers

Producers

Energy flowEnergy flow

• It is linear or one way• Once an organism has used energy it

is lost as heat and is unavailable for any other organism in the ecosystem

Human Impact on the Human Impact on the Antarctic food WebAntarctic food Web

Ryan PriviteraRyan Privitera

The Antarctic food webThe Antarctic food web

Everywhere in the world there are predators Everywhere in the world there are predators and prey meaning the lower you are on the and prey meaning the lower you are on the web means that you are a primary source to web means that you are a primary source to other species. other species.

Going from the diversity of the rain forest Going from the diversity of the rain forest where the web is large and complicated as where the web is large and complicated as compared to one of the simplest webs, the compared to one of the simplest webs, the Antarctic. Antarctic.

They call us humans.They call us humans.

The number one environmental problem we face The number one environmental problem we face as a society simply is our population growth. as a society simply is our population growth.

The more humans reproduce the worse off the The more humans reproduce the worse off the planet is going to be and the number increases planet is going to be and the number increases each day by 353015 babies.each day by 353015 babies.

The united states alone produces 10650 a day. The united states alone produces 10650 a day.

That’s an outrageous number and believe it or not That’s an outrageous number and believe it or not this is the main reason for impacting any food web this is the main reason for impacting any food web and we seem to disturb the simplest one.and we seem to disturb the simplest one.

Antarctica Antarctica

This is a place of vacancy which means no This is a place of vacancy which means no civilized human life forms live there year civilized human life forms live there year round for the reason that tempters can drop round for the reason that tempters can drop to -89.2 ° Celsius.to -89.2 ° Celsius.

This baron land is home to penguins, polar This baron land is home to penguins, polar bears, weddell seals, blackbrowed bears, weddell seals, blackbrowed albatross, leopard seals, elephant seals, albatross, leopard seals, elephant seals, and crabeater seals.and crabeater seals.

Human impactsHuman impacts

Antarctica is one of the most important research Antarctica is one of the most important research centers for environmental warming and melting of centers for environmental warming and melting of ice.ice.

Antarctica's clean air, water and ice of are of Antarctica's clean air, water and ice of are of importance to science for understanding how the importance to science for understanding how the Earth's environment is changing both naturally and Earth's environment is changing both naturally and as a result of human activity due to the increasing as a result of human activity due to the increasing hole over the Antarctic.hole over the Antarctic.

Pollution drifts into the air and contaminates the Pollution drifts into the air and contaminates the normal levels of our atmosphere. normal levels of our atmosphere.

This is the marine ecosystem.This is the marine ecosystem.

The simplicity of the food web.The simplicity of the food web.

Rusting metal in antarctica.Rusting metal in antarctica.

Rusted metal waste barrells.Rusted metal waste barrells.

Warming chartWarming chart

Realizing our mistakesRealizing our mistakes

The best way to fix any mistake is not to do The best way to fix any mistake is not to do it again so what we have to do as a society it again so what we have to do as a society is realize that what we do anywhere in the is realize that what we do anywhere in the world will have serious consequences if we world will have serious consequences if we keep living like Americans.keep living like Americans.

The ignorance of others will ruin this The ignorance of others will ruin this ecosystem if we simply keep overusing fuels ecosystem if we simply keep overusing fuels and not using renewable energies. and not using renewable energies.

Ecological Pyramids

Maddie Lewis

• Most energy going from one trophic level to the next dissipates into the environment due to the second law of thermodynamics.

• Ecological pyramids graphically represent relative energy levels at each level

• There are three types of ecological pyramids

Pyramid of Numbers

• Shows number of organisms at each trophic level, greater numbers are shown by a larger area

• In most, organisms at the base of the food chain are more abundant

• Inverted pyramids of numbers are when higher trophic levels have more organisms, seen in decomposers, parasites, etc.

Pyramid of Biomass

• Biomass- quantitive estimate of total mass or amount of living material, indicates fixed energy

• Represented as live weight, total volume or dry weight

• Succeeding trophic levels usually show reduction of biomass

Pyramid of Energy

• Illustrates energy of biomass at each level

• Usually measured in kilo-calories per year

• Always have large energy bases and get progressively smaller

• Less energy reaches each level because organisms use it, and some is lost

• Food webs are short due to dramatic reduction in energy

ECOSYSTEM ECOSYSTEM PRODUCTIVITYPRODUCTIVITY

MERICA

Gross Primary ProductivityGross Primary Productivity

• GPP of an ecosystem is the rate GPP of an ecosystem is the rate at which energy is captured during at which energy is captured during photosynthesis!photosynthesis!

MERICA

Net Primary ProductivityNet Primary Productivity

• NPP is energy in plant tissues after NPP is energy in plant tissues after cellular respiration has occurred!cellular respiration has occurred!

• NPP is the amount of biomass found NPP is the amount of biomass found in excess of that broken down by in excess of that broken down by plant’s cellular respiration!plant’s cellular respiration!

GPP=NPP + Respiration

More!More!

• Both GPP and NPP are expressed as Both GPP and NPP are expressed as energy per unit area per unit time, or as energy per unit area per unit time, or as dry weight.dry weight.

• Consumers use most energy from NPP for Consumers use most energy from NPP for cellular respiration and to contract cellular respiration and to contract muscles.muscles.

RECENTLYRECENTLY

• In 1986 In 1986 Peter Vitousek Peter Vitousek calculated how much of global calculated how much of global NPP is appropiated for the human economy and NPP is appropiated for the human economy and therefore not transferred to other organisms. He therefore not transferred to other organisms. He determined humans use 32% of the annual NPP of land-determined humans use 32% of the annual NPP of land-based organisms.based organisms.

• In 2001 In 2001 Stuart Rojstaczer Stuart Rojstaczer reexamined Vitousek’s reexamined Vitousek’s experiment and agreed with his result of 32% usage.experiment and agreed with his result of 32% usage.

• In 2007 In 2007 K. Heinz Erb K. Heinz Erb put 97% of the Earth’s forestry put 97% of the Earth’s forestry information into a computer model. The model states information into a computer model. The model states humans are appropriated about 25%.humans are appropriated about 25%.