1. Ecosystems
Chapter 30

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

3. Modes of Nutrition Photoautotrophs Heterotrophs
Capture sunlight or chemical energy
Primary producers
Heterotrophs
Extract energy from other organisms or organic wastes
Consumers, decomposers, detritivores

4. 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)

5. Simple Ecosystem Model
The role of organisms in an ecosystem

6. (fourth-level consumer) (third-level consumer) (second-level consumer)
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

7. Tall-Grass Prairie Food Web
marsh hawk
sandpiper
crow
snake
frog
weasel
badger
coyote
spider
sparrow
pocket
gopher
ground
squirrel
vole
earthworms, insects
grasses, composites

8. tallgrass prairie food web
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
earthworms, insects
prairie vole
pocket gopher
ground squirrel
First Trophic Level
grasses, composites
Fig. 30-4, p.529

9. Which statement about ecosystems is false?
energy flows in a cycle between producers and consumers
nutrients are recycled by passing from producers to consumers and back again via decomposers
in most ecosystems, energy flow begins with the capture of solar energy by photosynthesizers
heterotrophs include bacteria and fungi

10. Rain Forest
Rain-forest food web

11. Energy Losses Energy transfers are never 100% efficient
Some energy is lost at each step
Limits number of trophic levels in an ecosystem

12. Two Types of Food Webs Grazing Food Web Detrital Food Web
Energy Input:
Energy Input:
Transfers:
Transfers:
Producers (photosynthesizers)
Producers (photosynthesizers)
energy losses
as metabolic heat
and as net export
from ecosystem
energy
in organic wastes, remains
energy losses
as metabolic heat
and as net export
from ecosystem
energy
in organic wastes, remains
herbivores
decomposers
decomposers
carnivores
detritivores
detritivores
decomposers
Energy Output
Energy Output

13. 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

14. 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)
decomposers, detritivores
(bacteria, crayfish)
1.1
first-level consumers
(herbivorous fishes,
turtles, invertebrates) 37
primary producers (algae,
eelgrass, rooted plants)
809 5

15. Energy Pyramid
Primary producers trapped about 1.2% of the solar energy that entered the ecosystem
6–16% passed on to next level
top carnivores 21
decomposers + detritivores = 5,080
carnivores
383
herbivores
3,368
producers
20,810 kilocalories/square meter/year

16. Energy flow at Silver Springs
Silver Springs Study
Energy flow at Silver Springs

17. 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

18. Three Categories Hydrologic cycle Atmospheric cycles
Water
Atmospheric cycles
Nitrogen and carbon
Sedimentary cycles
Phosphorus and other nutrients

19. Hydrologic Cycle atmosphere precipitation onto land 111,000
wind-driven water vapor
40,000
evaporation from ocean
425,000
precipitation into ocean 385,000
evaporation from land plants (evapotranspiration) 71,000
surface and groundwater flow 40,000
ocean
land

20. Watershed
A region where precipitation is funneled into a single stream or river

21. Hubbard Brook Experiment
A watershed was experimentally stripped of vegetation
All surface water draining from watershed was measured
Deforestation caused six-fold increase in calcium content of runoff water

22. 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

23. Aquifer Depletion
Hawaiian Islands
Alaska

24. water hydrologic hydrodynamic precipitation
When the Earth's waters move from ocean to atmosphere to land and back again, it is called the _____ cycle.
water
hydrologic
hydrodynamic
precipitation

25. A watershed is _____. a stream or river
a river that discharges water directly into the ocean
a region where precipitation becomes funneled into a single stream or river
a region where precipitation becomes funneled into a reservoir for use in human communities

26. 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

27. bicarbonate and carbonate in ocean water
diffusion between atmosphere and ocean
combustion of fossil fuels
bicarbonate and carbonate in ocean water
photosynthesis
aerobic respiration
marine food webs
death, sedimentation
incorporation into sediments
uplifting
sedimentation
marine sediments
Carbon Cycle: Marine

28. combustion of fossil fuels
atmosphere
volcanic action
combustion of fossil fuels
photosynthesis
aerobic respiration
combustion of wood
terrestrial rocks
deforestation
weathering
land food
webs
soil water
peat,
fossil
fuels
death, burial, compaction over geologic time
leaching, runoff
Carbon Cycle: Land

29. My Carbon Cycle 1. I eat carbohydrate molecules.
These are molecules of fuel which I will “burn”.
Some of the energy released when I burn them will be trapped for me to use. The rest will be lost as heat.
The waste products of burned fuel are carbon dioxide and water. I breathe these out.
Plants (or other producers) take in carbon dioxide from the atmosphere and use it to make carbohydrate.

30. According to the last slide, why do I eat carbohydrates?
Because they taste good.
Because they contain lots of vitamins.
Because they contain lots of energy.
Because they are low in calories.

31. Energy saved from burning up my fuel is saved in the form of :
Muscle
ATP
Fat
Heat

32. The only reason I need to breathe in oxygen is :
I need oxygen to “burn” fuel molecules.
All living things need oxygen.
Oxygen + carbon = carbon dioxide.
Oxygen is corrosive.

33. Breathing out : Helps me regulate my body temperature.
Gets rid of excess fuel molecules.
Burns extra calories.
Gets rid of the waste products of burned fuel.

34. The carbon in the plants I eat comes from :
The atmosphere.
The food they eat.
The soil.
Water.

35. The carbon in the steak I eat comes from :
Supplements in animal feed.
Vitamins.
The cow’s drinking water.
The plants eaten by the cow.

36. Greenhouse Effect
Greenhouse gases impede escape of heat from Earth’s surface

37. Long-term increase in temperature of Earth’s lower atmosphere
Global Warming
Long-term increase in temperature of Earth’s lower atmosphere

38. Carbon Dioxide Increase
Carbon dioxide levels fluctuate seasonally
Average level is steadily increasing
Burning of fossil fuels and deforestation are contributing to the increase

39. 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

40. Greenhouse Gases Increasing

41. Table 30-1, p.537

42. 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

43. Fig , p.538

44. Nitrogen Fixation Plants cannot use nitrogen gas
Nitrogen-fixing bacteria convert nitrogen gas into ammonia (NH3)
Ammonia and ammonium can be taken up by plants

45. Air Pollution
Effects of nitrogen oxides released by burning fossil fuels