Download Energy Transfer

Energy Transfer
PAGES 368-369
Tropic Level
•Trophic level: position in a series of energy transfers
Trophic Levels
•Only 10% of the total energy is passed onto the next trophic
level
◦Energy lost to biological processes (digestion, growth
and repair, running, walking etc.)
◦Energy lost as heat
90 % Energy
Lost
90 % Energy
Lost
90 % Energy
Lost
Large
Carnivore
• 3˚ Consumer
• Ex: killer whale
Small
Carnivore
• 2˚Consumer
• Ex: sea otter
Herbivore
• 1˚
Consumer
• Ex: sea
urchin
Producer
• Ex:
Kelp
Energy flows through ecosystems
sun
secondary
consumers
(carnivores)
primary consumers
(herbivores)
producers (plants)
loss of
energy
loss of
energy
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.