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Ecosystems. Chapter 30. Bye-Bye Bayou. Louisiana’s coastal wetlands are disappearing Global warming contributes to wetland’s demise Sea levels rising worldwide Burning fossil fuels raises global temperature. Impacts, Issues Video. Bye-Bye, Blue Bayou. Ecosystem.

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ecosystems

Ecosystems

Chapter 30

bye bye bayou
Bye-Bye Bayou
  • Louisiana’s coastal wetlands are disappearing
  • Global warming contributes to wetland’s demise
  • Sea levels rising worldwide
  • Burning fossil fuels raises global temperature
impacts issues video
Impacts, Issues Video

Bye-Bye, Blue Bayou

ecosystem
Ecosystem

An array of organisms and their physical environment, interconnected through a one-way flow of energy and cycling of raw materials

modes of nutrition
Modes of Nutrition
  • Photoautotrophs
    • Capture sunlight or chemical energy
    • Primary producers
  • Heterotrophs
    • Extract energy from other organisms or organic wastes
    • Consumers, decomposers, detritivores
simple ecosystem model
Simple Ecosystem Model

Energy input from sun

Producers

Autotrophs (plants and other self-feeding organisms)

Nutrient

Cycling

Consumers

Heterotrophs (animals, most fungi,

many protists, many bacteria)

Energy output (mainly metabolic heat)

simple ecosystem model1
Simple Ecosystem Model

The role of organisms in an ecosystem

consumers

SPRING

Consumers
  • Herbivores
  • Carnivores
  • Parasites
  • Omnivores
  • Decomposers
  • Detritivores

fruits

insects

rodents, rabbits

birds

SUMMER

fruits

rodents, rabbits

insects

birds

seasonal variation in the diet of an omnivore (red fox)

trophic levels
Trophic Levels
  • Feeding relationships
    • All organisms at a trophic level are the same number of steps away from the energy input into the system
  • Autotrophs are producers
    • closest to energy input
    • first trophic level
trophic levels1
Trophic Levels

Fourth-level consumers (heterotrophs):

5th

Top carnivores, parasites, detritivores, decomposers

Third-level consumers (heterotrophs):

4th

Carnivores, parasites, detritivores, decomposers

Second-level consumers (heterotrophs):

3rd

Carnivores, parasites, detritivores, decomposers

First-level consumers (heterotrophs):

2nd

Herbivores, parasites, detritivores, decomposers

Primary producers (autotrophs):

1st

Photoautotrophs, chemoautotrophs

slide11

fifth trophic level

top carnivore

(fourth-level consumer)

marsh hawk

fourth trophic level

carnivore

(third-level consumer)

crow

third trophic level

carnivore

(second-level consumer)

garter snake

second trophic level

herbivore

(primary consumer)

cutworm

first trophic level

autotroph

(primary producer)

flowering plants

Fig. 30-3, p.528

food chain
Food Chain

Food chain

food chain1
Food Chain

marsh hawk

  • A straight-line sequence of who eats whom
  • Simple food chains are rare in nature

upland sandpiper

garter snake

cutworm

plants

slide14

marsh hawk

Connections in a

tallgrass prairie food web

Higher Trophic Levels

crow

upland sandpiper

garter snake

frog

weasel

badger

coyote

spider

Second Trophic Level

sparrow

prairie vole

pocket gopher

ground squirrel

earthworms, insects

First Trophic Level

grasses, composites

Fig. 30-4, p.529

rain forest
Rain Forest

Rain-forest food web

energy losses
Energy Losses
  • Energy transfers are never 100% efficient
  • Some energy is lost at each step
  • Limits number of trophic levels in an ecosystem
biological magnification
Biological Magnification

Nondegradable or slowly degradable substances become more and more concentrated in tissues of organisms at higher trophic levels of a food web

ddt in food webs
DDT in Food Webs
  • Synthetic pesticide banned in United States since 1970s
  • Carnivorous birds accumulate DDT in their tissues, produce brittle egg shells
ecological pyramids
Ecological Pyramids
  • Primary producers are bases for successive tiers of consumers
  • Biomass pyramid
    • Dry weight of all organisms
  • Energy pyramid
    • Usable energy decreases as it is transferred through ecosystem
biomass pyramid
Biomass Pyramid
  • Aquatic ecosystem, Silver Springs, Florida
  • Long-term study of a grazing food web

third-level carnivores

(gar, large-mouth bass)

1.5

second-level consumers

(fishes, invertebrates)

1.1

decomposers, detritivores

(bacteria, crayfish)

first-level consumers

(herbivorous fishes,

turtles, invertebrates)

37

primary producers (algae,

eelgrass, rooted plants)

809

5

energy pyramid
Energy Pyramid
  • Primary producers trapped about 1.2% of the solar energy that entered the ecosystem
  • 6–16% passed on to next level

decomposers + detritivores = 5,080

21

top carnivores

carnivores

383

herbivores

3,368

producers

20,810 kilocalories/square meter/year

silver springs study
Silver Springs Study

Energy flow at Silver Springs

biogeochemical cycle
Biogeochemical Cycle
  • Flow of an essential substance from the environment to living organisms and back to the environment
  • Main reservoir is in the environment
  • Geologic processes, decomposers aid cycles
three categories
Three Categories
  • Hydrologic cycle
    • Water
  • Atmospheric cycles
    • Nitrogen and carbon
  • Sedimentary cycles
    • Phosphorus and other nutrients
hydrologic cycle
Hydrologic Cycle

atmosphere

precipitation onto land 111,000

wind-driven water vapor

40,000

evaporation from land plants (evapotranspiration) 71,000

evaporation from ocean

425,000

precipitation into ocean 385,000

surface and groundwater flow 40,000

land

ocean

hydrologic cycle1
Hydrologic Cycle

Hydrologic cycle

global water crisis
Global Water Crisis
  • Limited amount of fresh water
  • Desalinization is expensive and requires large amounts of energy
  • Aquifers are being depleted
  • Groundwater is contaminated
  • Sewage, agricultural runoff, and industrial chemicals pollute rivers
aquifer problems
Aquifer Problems

Threats to aquifers

carbon cycle
Carbon Cycle
  • Carbon moves through atmosphere, food webs, ocean, sediments, and rocks
  • Sediments and rocks are the main reservoir
  • Combustion of fossil fuels changes natural balance
carbon cycle1
Carbon Cycle

Carbon cycle

greenhouse effect
Greenhouse Effect
  • Greenhouse gases impede escape of heat from Earth’s surface
greenhouse effect1
Greenhouse Effect

Greenhouse effect

global warming
Global Warming

Long-term increase in temperature of Earth’s lower atmosphere

greenhouse gases
Greenhouse Gases

Carbon dioxide and temperature

carbon dioxide increase
Carbon Dioxide Increase
  • Carbon dioxide levels fluctuate seasonally
  • Average level is steadily increasing
  • Burning of fossil fuels and deforestation are contributing to the increase
other greenhouse gases
Other Greenhouse Gases
  • CFCs: synthetic gases used in plastics and in refrigeration
  • Methane: released by natural gas production, livestock
  • Nitrous oxide: released by bacteria, fertilizers, and animal wastes
greenhouse gases1
Greenhouse Gases

Greenhouse gases

nitrogen cycle
Nitrogen Cycle
  • Nitrogen is used in amino acids and nucleic acids
  • Main reservoir is nitrogen gas in the atmosphere
  • Nitrogen gas can’t enter food web
nitrogen cycle1
Nitrogen Cycle

Nitrogen cycle

human effects
Human Effects
  • Humans increase rate of nitrogen loss by clearing forests and grasslands
  • Humans increase nitrogen in water and air by using fertilizers and by burning fossil fuels
  • Too much or too little nitrogen can compromise plant health
air pollution
Air Pollution
  • Effects of nitrogen oxides released by burning fossil fuels
deforestation
Deforestation

Effect of air pollution in forests

phosphorus cycle
Phosphorus Cycle
  • Phosphorus is part of phospholipids, nucleotides, NADH, ATP
  • Main limiting factor in ecosystems
  • Reservoir is Earth’s crust; no gaseous phase
phosphorus cycle1
Phosphorus Cycle

Phosphorus cycle

human effects1
Human Effects
  • In tropical countries, clearing lands for agriculture may deplete phosphorus-poor soils
  • In developed countries, fertilizer causes phosphorus overloads in soil
eutrophication
Eutrophication
  • Phosphorus is limiting factor in many freshwater ecosystems
  • Runoff from phosphate fertilizers accelerates algal growth in waterways
  • Resulting dense algal blooms cause system overload and death