Transcript Energy Flow - Dr. M's Class

Energy Flow in
an Ecosystem
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1
Energy Flow
• Energy in an ecosystem originally
comes from the sun
• Energy flows through Ecosystems
from producers to consumers
– Producers (make food)
– Consumers (use food by eating
producers or other consumers)
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Feeding Relationships
Energy flows
through an
ecosystem in
one direction.
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Feeding Relationships
•
There are 3 main types of feeding
relationships
1. Producer - Consumer
2. Predator - Prey
3. Parasite - Host
Feeding Relationships
Producer- all
autotrophs (plants),
they trap energy
from the sun
• Bottom of the food
chain
Feeding Relationships
Consumer- all heterotrophs: they
ingest food containing the sun’s
energy
Herbivores
Carnivores
Omnivores
Decomposers
Feeding Relationships
CONSUMERS
1.Primary consumers
• Eat plants
• Herbivores
• Secondary, tertiary
… consumers
• Prey animals
• Carnivores
Feeding Relationships
Consumer-Carnivores-eat meat
• Predators
– Hunt prey
animals for food.
Feeding Relationships
Consumer- Carnivores- eat meat
• Scavengers
– Feed on carrion,
dead animals
Feeding Relationships
Consumer- Omnivores -eat both plants
and animals
Feeding Relationships
ConsumerDecomposers
• Breakdown the
complex compounds
of dead and
decaying plants and
animals into simpler
molecules that can
be absorbed
Food Chain
1st
order
Consumer
2nd Order
Consumer
3rd
Order
consumer
4th Order
Consumer
Producer (trapped
sunlight & stored food)
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Arrows are drawn in the direction of energy
flow.
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Trophic Levels
Each Level In A Food Chain or Food
Web is a Trophic Level.
• Producers
– Always The First Trophic Level
– How Energy Enters The System
• Herbivores
– Second Trophic Level
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Trophic Levels
• Trophic levels represent a feeding
step in the transfer of energy
and matter in an ecosystem.
Trophic Levels
Food chain- simple model that
shows how matter and energy
move through an ecosystem
Name the Producer, Consumers
& Decomposers in this food
chain:
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Trophic Levels
Food web- shows all possible
feeding relationships in a
community at each trophic level
• Represents a network of
interconnected food chains
Food chain
(just 1 path of energy)
Food web
(all possible energy paths)
Trophic Levels
Biomass- the amount of organic matter
comprising a group of organisms in a
habitat.
• As you move up a food chain, both
available energy and biomass
decrease.
• Energy is transferred upwards but is
diminished with each transfer.
E
N
E
R
G
Y
Trophic Levels
Tertiary
consumers- top
carnivores
Secondary consumerssmall carnivores
Primary consumers- Herbivores
Producers- Autotrophs
RULE OF 10
• Only 10% of energy is transferred from one trophic
level to the next.
• Example:
– It takes 100 kgs of plant materials (producers) to support
10 kgs of herbivores
– It takes 10 kgs of herbivores to support 1 kg of 1st level
predator
Trophic Levels
• Carnivores/Omnivores
– Make Up The Remaining
Trophic Levels
Each level depends on the
one below it for energy.
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Ecological Pyramids
Graphic Representations Of The
Relative Amounts of Energy or
Matter At Each Trophic Level
May be:
Energy Pyramid
Biomass Pyramid
Pyramid of Numbers
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Energy Pyramid
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Biomass Pyramid
the total mass of
living matter at
each level.
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Pyramid of Biomass
• Rapid consumption of producers in some marine
ecosystems
– Rapidly reproducing
producers support
larger consumer
population
– Leads to inverted
biomass pyramid
Pyramid of Numbers
Each level
represents the
number of
organisms
consumed by the
level above it.
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Toxins in food chainsWhile energy decreases as it moves up
the food chain, toxins increase in
potency.
•This is called biomagnification
Ex: DDT & Bald Eagles