Notes 2.2: Energy Flow - losal.org · Trophic Levels •Only 10% of the total energy is passed onto...
Transcript of Notes 2.2: Energy Flow - losal.org · Trophic Levels •Only 10% of the total energy is passed onto...
Notes 2.2: Energy Flow PAGES 366-369
Energy Flow in an EcosystemSun autotrophs heterotrophs
producers consumers
Producers/Autotrophs•Can make their own food through photosynthesis or chemosynthesis
Productivity•Productivity: energy made by producers (after biological processes) available to consumers
•Gross primary productivity (GPP): rate at which producers capture energy in organic compounds
Productivity•Net primary productivity (NPP): the rate at which biomass accumulates (after some is used)•NPP= GPP – Cellular Respiration• Cellular Respiration = making energy for the plant’s survival
Productivity•Biomass: the amount of organic (living) material produced
Consumers•Get energy by eating other organisms
•There are 5 types
Consumers
•Herbivores: eat producers
Consumers•Carnivores: eat other consumers
Consumers•Omnivores: eat producers and consumers
Consumers•Detritivores: feed on “garbage” or dead organic matter (ex. worms, millipedes, vultures)
Consumers•Decomposer: break down dead organic matter into simpler molecules (fungi and bacteria)•Recycle nutrients back into ecosystem
Food Chain•Food chain: a single pathway of feeding relationships in an ecosystem that traces the transfer of energy
Food Web•Interconnected food chains
•Arrows show transfer of energy
Trophic Level•Trophic level: position in a series of energy transfers
Energy flows through ecosystems
sun
producers (plants)
loss of
energy
loss of
energy
secondary
consumers
(carnivores)
primary consumers
(herbivores)
Trophic Levels•Only 10% of the total energy is passed onto the next trophic level (rule of 10%)
◦Energy lost to biological processes (digestion, growth and repair, running, walking etc.)
◦Energy lost as heat
• 3˚ Consumer
• Ex: killer whaleLarge
Carnivore
• 2˚Consumer
• Ex: sea otterSmall
Carnivore
• 1˚ Consumer
• Ex: sea urchin
Herbivore
• Ex: Kelp
Producer
90 % Energy
Lost
90 % Energy
Lost
90 % Energy
Lost
Question: Why is a pyramid used to display energy transfer and not a square?
Approximately 90% loss of energy at each trophic level
Keystone Species•Has disproportionately large effect on the ecosystem
•Dictates community structure
•Demonstrated by removal of keystone species from community•Ex. Sea stars, otters
Sea star feeds on all
bivalves. When the
sea star is removed
from the tide pools
one bivalve (mussel)
out competes the rest
for resources and
becomes the dominant
species.