ENVI SCI Lecture 3

8/8/2019 ENVI SCI Lecture 3

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ENVIRONMENTAL SCIENCE 13e

CHAPTER 3:Ecosystems: What AreThey and How Do

They Work?

Earth Has Four Major Life-Support Components

Atmosphere (air)

Hydrosphere Geosphere (lithosphere)

Biosphere

Fig. 3-2, p. 41

Rock

Crust

Atmosphere

Vegetationand animals

Biosphere

Mantle

Lithosphere

Soil

Geosphere(crust, mantle, core)

Mantle

Core

Crust(soil and rock)

Biosphere(living organisms)

Atmosphere(air)

Hydrosphere(water)

Three Factors Sustain Life onEarth

One-way flow of high-quality energyfrom the sun

Cycling of matter or nutrients through

parts of the biosphere

Gravity

Levels of Organization of

Matter in Nature

Ecologyfocuses on fiveof these levels

Organism

Any formof life

Can be

classifiedintospecies


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Ecosystems

All members of a community,

along with their physical andchemical environments

Vary greatly in size

Diversity promotes stability andproductivity

Dynamic energy flow

chemical cycling

Change over time (succession)

Coral Reefs are a rich,diverse and productive

ecosystems

A coastal wetland onLake Superior,

Wisconsin.

Ecology

How organisms interact with biotic

and abiotic environment Focuses on specific levels of matter:

Organisms

Populations

Communities

Ecosystems

Biosphere

Fig. 3-4, p. 42

Smallest unit of a chemical elementthat exhibits its chemical properties

Biosphere

Ecosystem

Community

Population

Organism

Cell

Molecule

Atom

Parts of the earth's air,water, and soilwhere life is found

Acommunity of different speciesinteracting with one another and with

their nonliving environment of matterand energy

Populations of different speciesliving in a particular place, and

potentially interacting with eachother

A group of individuals of the samespecies living in a particular place

An individual living being

The fundamental structural andfunctional unit of life

Chemical combination of two ormore atoms of the same or different

elements

Fig. 3-4, p. 42

Water

Hydrogen Oxygen

Living and NonlivingComponents (1)

Abiotic Water

Air

Nutrients

Solar energy

Rocks

Heat

Living and NonlivingComponents (2)

Biotic Plants

Animals

Microbes

Dead organisms

Waste products of dead organisms


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Soluble mineralnutrients

Producers

Decomposers

Secondaryconsumer

(fox)

Carbon dioxide (CO2)

Primaryconsumer

(rabbit)

Producer

Oxygen (O2)Precipitation

Water

Fig. 3-5, p. 43

Trophic Levels (1)

Producers autotrophs

Photosynthesis

Consumers heterotrophs

Primary - herbivores

Secondary - carnivores

Third-level- Omnivores

Trophic Levels (2)

Decomposers

Release nutrients from the dead bodies

of plants and animals

Detrivores

Feed on the waste or dead bodies of

organisms

Time

progression Powder broken dow n by

decomposers into plantnutrients in soil

MushroomWoodreducedto powder

Dry rotfungus

Termite andcarpenterant work

DecomposersDetritus feeders

Carpenterant galleriesBark beetle

engravingLong-hornedbeetle holes

Fig. 3-6, p. 44

Primary Production

The conversion of light

energy to chemical energy iscalled gross primary

production. (photosynthesis)

Plants use the energy

captured in photosynthesis

for maintenance and growth.

The energy that is

accumulated in plant

biomass is called net

primary production.


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Biological Processes

Photosynthesis

Respiration

Photosynthetically ActiveRadiation (PAR)

Light

wavelenghts:400 700 nm

Drivesphotosynthetic

reactions

Photosynthesis

The Leaf as Site ofPhotosynthesis

PhotosyntheticPathways

C3(Calvin Cycle)

C4 (Hatch andSlack)


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CrassulaceanAcidMetabolism(CAM) Photosynthetic

pathway forxerophytic plants

Dissimilar Organisms with Similar Approaches to Desert Living

Water Conservation of

Rain Forest Plants

Temporarywilting reducesleaf surfacearea for

transpiration.

Production and Consumption ofEnergy

Photosynthesis

Carbon dioxide + water + solarenergyglucose + oxygen

Aerobic respiration

Glucose + oxygen carbon dioxide+ water + energy

Energy Flow and NutrientRecycling

Ecosystems sustained through: One-way energy flow from the sun

Nutrient recycling

Abiotic chemicals(carbon dioxide,

oxygen, nitrogen,minerals)

Decomposers(bacteria, fungi)

Consumers(herbivores,carnivores)

Producers(plants)

Solarenergy

Heat

Heat Heat

Heat Heat

Fig. 3-7, p. 45


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Science Focus: InvisibleOrganisms (1)

Microorganisms/Microbes

Bacteria Protozoa

Fungi

Phytoplankton

Science Focus: InvisibleOrganisms (2)

Microbes can cause disease

Malaria Athletes foot

Microbes are also beneficial

Intestinal flora

Purify water

Phytoplankton remove carbon dioxidefrom the atmosphere

Energy Flow in Ecosystems

Food chains and web show how eaters,the eaten, and the decomposed areconnected to one another.

Food chain is a sequence of organisms,each of which is a source of food for thenext.

Food web is a complex network of

interconnected food chains.

A Food Chain

Humans

Squid

Herbivorouszooplankton

Phytoplankton

Krill

Fish

Petrel

Adeliepenguin

Sperm whale

Emperorpenguin

Leopardseal

Killer

whale

Crabeaterseal

Elephantseal

Blue whale

Carnivorousplankton

Fig. 3-9, p. 46

Two Kinds of PrimaryProductivity

Gross primary productivity (GPP)

Net primary productivity (NPP)

Planets NPP limits number ofconsumers

Humans use, waste, or destroy 10-55% of earths total potential NPP

Human population is less than 1% oftotal biomass of earths consumers


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3-4 What Happens to Matter inan Ecosystem?

Concept 3-4Matter, in the form of

nutrients, cycles within and amongecosystems and in the biosphere, andhuman activities are altering thesechemical cycles.

Biogeochemical Cycles

Nutrient cycles

Reservoirs Connect all organisms through time

Hydrologic Cycle

Water cycle is powered by the sun

1. Evaporation

2. Precipitation

3. Transpiration - evaporates from plant

surfaces

Water vapor in the atmosphere comes

from the oceans 84%

Over land, ~90% of water reaching theatmosphere comes from transpiration

Increasedfloodingfrom wetlanddestruction

Condensation

Evaporationfrom ocean

Climatechange

Infiltrationand percolationinto aquifer

Condensation

Ocean

Lakes andreservoirs

Ice andsnow

Surfacerunoff

Surface runoff

Aquiferdepletion fromoverpumping

Pointsourcepollution

Reduced recharge ofaquifers and floodingfrom covering landwith crops andbuildings

Groundwatermovement (slow)

Runoff

Precipitationto land

Precipitationto ocean

Transpirationfrom plants

Evaporationfrom land

Fig. 3-12, p. 49

Processes

Processes affected by humans

Reservoir

Pathway affected by humans

Natural pathway

Carbon Cycle

Based on carbon dioxide (CO2)

CO2 makes up 0.038% of atmospherevolume

Major cycle processes Aerobic respiration

Photosynthesis

Fossil fuel combustion and deforestation

Fossil fuels add CO2 to the atmosphereand contribute to global warming

Respiration

Forest fires

Deforestation

Diffusion

Carbon dioxidedissolved in ocean

Carbonin limestone or

dolomite sediments

Marine food websProducers, consumers,

decomposers

Transportation

Carbon dioxidein atmosphere

Carbonin animals

(consumers)

Plants(producers)

Animals(consumers)

Decomposition

Respiration

Compaction

Carbonin fossil

fuels

Carbonin plants

(producers)

Burningfossil fuels

Photosynthesis

Fig. 3-13, p. 51

Processes

Reservoir


Natural pathway


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Nitrogen Cycle

Multicellular plants and animals

cannot utilize atmospheric nitrogen(N2)

Nitrogen fixation (N2 --- NO3 )

Nitrification (NO3 --- NH4)

Denitrification

Nitrogenin atmosphere

Nitrogenloss to deepocean sediments

Nitrogen oxidesfrom burning fuel

Nitratesfrom fertilizer

runoff anddecomposition

Nitrogenin oceansediments Ammonia

in soil

Volcanicactivity

Electricalstorms Nitrogen

in animals(consumers)

Bacteria

Nitrate

in soil

Nitrogenin plants

(producers)

Nitrificationby bacteria

Denitrificationby bacteria

Uptake by plantsDecomposition

Fig. 3-14, p. 52

Processes

Reservoir


Natural pathway

Phosphorus Cycle

Does not cycle through theatmosphere

Obtained from terrestrial rock

formations

Limiting factor on land and infreshwater ecosystems

Biologically important for producers

and consumersFig. 3-15, p. 53

Seabirds

Phosphatein shallowocean sediments

Bacteria

Animals(consumers)

Plants

(producers)

Runoff

Runoff Runoff

Phosphatesin fertilizer

Phosphates

in mining waste

Phosphatesin sewage

Phosphatedissolved inwater

Erosion

Phosphatein deepocean

sediments

Oceanfood chain

Platetectonics

Phosphatein rock

(fossil bones,guano)

Fig. 3-15, p. 53

Processes

Reservoir


Natural pathway

Sulfur Cycle

Most sulfur stored in rocks and minerals Enters atmosphere through:

Volcanic eruptions and processes

Anaerobic decomposition in swamps,bogs, and tidal flats

Sea spray

Dust storms

Forest fires


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ENVI SCI Lecture 3

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