Transcript Plants and Pollinators

Ecosystems
Chapter 43
Ecosystem
An association of organisms and their
physical environment, interconnected by
ongoing flow of energy and a cycling of
materials
Modes of Nutrition
• Autotrophs
– Capture sunlight or chemical energy
– Producers
• Heterotrophs
– Extract energy from other organisms or
organic wastes
– Consumers, decomposers, detritivores
Consumers
• Herbivores
• Carnivores
• Parasites
• Omnivores
• Decomposers
• Detritivores
Trophic Levels
• All the organisms at a trophic level are
the same number of steps away from
the energy input into the system
• Producers are closest to the energy
input and are the first trophic level
Trophic Levels in Prairie
5th
4th
Fourth-level consumers (heterotrophs):
Top carnivores, parasites,
detritivores, decomposers
Third-level consumers (heterotrophs):
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
Food Chain
MARSH
HAWK
• A straight line
sequence of who
UPLAND
SANDPIPER
eats whom
• Simple food chains
GARTER SNAKE
are rare in nature
CUTWORM
Food
Web
Energy Losses
• Energy transfers are never 100 percent
efficient
• Some energy is lost at each step
• Limits the number of trophic levels in an
ecosystem
Biomass Pyramid
Biomass
pyramid
decomposers,
detritivores
5
(bacteria,
crayfish)
third-level carnivores
(gar, large-mouth bass)
1.5
1.1
second-level consumers
(fishes, invertebrates)
37
first-level consumers
(herbivorous fishes,
turtles, invertebrates)
809
primary producers (algae,
eelgrass, rooted plants)
Biological Magnification
A nondegradable or slowly degradable
substance becomes more and more
concentrated in the tissues of
organisms at higher trophic levels of a
food web
Pyramid of Energy Flow
• 10% passed on to next level
top carnivores
21
carnivores
herbivores
383
decomposers
3,368
producers
20,810 kilocalories/square meter/year
detritivores
All Heat in the End
• At each trophic level, the bulk of the
energy received from the previous level
is used in metabolism
• This energy is released as heat energy
and lost to the ecosystem
• Eventually, all energy is released as
heat
Carbon Cycle
diffusion
Atmosphere
Bicarbonate,
volcanic action
carbonate
Marine
food
TERRESTRIAL
webs ROCKS
Terrestrial
Rocks
photosynthesis
Land Food
Webs
Soil Water
Marine Sediments
weathering
Peat, Fossil
Fuels
Carbon in the Oceans
• Most carbon in the ocean is dissolved
carbonate and bicarbonate
• Ocean currents carry dissolved carbon
Carbon in Atmosphere
• Atmospheric carbon is mainly carbon
dioxide
• Carbon dioxide is added to
atmosphere
– Aerobic respiration, volcanic action,
burning fossil fuels
• Removed by photosynthesis
Greenhouse Effect
• Greenhouse gases impede the escape
of heat from Earth’s surface
Global Warming
• Long-term increase in the temperature
of Earth’s lower atmosphere
Carbon Dioxide Increase
• Carbon dioxide levels fluctuate
seasonally
• The average level is steadily increasing
• Burning of fossil fuels and deforestation
are contributing to the increase
Other Greenhouse Gases
• CFCs - synthetic gases used in plastics
and in refrigeration
• Methane - produced by termites and
bacteria
• Nitrous oxide - released by bacteria,
fertilizers, and animal wastes
Effects of Global Warming
• Global Climate Changes = More Storms
& More Violent Storms
• Drought & Regional Weather Changes
• Melting of Glaciers and Polar Ice Caps
• Rise in Sea Level