• Energy
– From sun or chemicals
• Raw materials to make building blocks of life
– From food
• Sunlight is the main energy source for life on Earth
• Autotrophs will use energy from the sun to convert
carbon dioxide and water into oxygen and
carbohydrates (photosynthesis!)
6CO2 + 6H2O  C6H12O6 + O2
• Autotrophs are also known as producers
• Examples:
– Plants
– Algae
– Cyanobacteria
• What if there is no light in the ecosystem?
• The autotrophs will use chemosynthesis,
which is a process that uses chemical energy
to produce carbohydrates (ex: bacteria living
in volcanic vents)
• Organisms that rely on other organisms for
energy are known as consumers or
heterotrophs
•
•
•
•
Herbivores- consume only plants
Carnivores- consume only meat
Omnivores- consume both plants and animals
Detritivores- consume plant and animal remains
(earthworms, mites, crabs)
• Decomposer= breaks down organic matter to obtain
energy (bacteria & fungi)
• Energy in an ecosystem flows in one direction
(from sun to the heterotrophs)
• Food chain- a series of steps in which
organisms transfer energy by eating and being
eaten
• Each step in a food chain or food web is called
a trophic level
• Autotrophs make up the first trophic level,
consumers make up 2nd, 3rd, 4th or higher
level
Producers
• Base of all food chains
• Autotrophic (manufacture organic molecules)
• Energy source – does not come from other
living things (i.e. sunlight or chemical energy)
• Raw materials – Inorganic
compounds (i.e. CO2, H2S, H2O)
• Examples:
• Photosynthetic organisms (i.e.
plants, algae, cyanobacteria)
• Chemosynthetic organisms (i.e.
archae-bacteria in deep ocean vents)
Detritivores
Heterotrophic
Utilize energy and raw materials
from dead or decaying organisms
End of all food chains
Decomposers
Reduce organic molecules
to inorganic compounds
Examples: worms, bacteria, fungi, termites
Consumers
 Heterotrophic
 Utilize energy and raw materials
obtained from other living things
Herbivores =
Primary Consumers
 Acquire energy by ingesting autotrophic organisms (usually plants)
 Examples: rabbits, deer, bees
Carnivores
 Predators & scavengers
Secondary Consumers
 Acquire energy from
flesh of herbivores
Tertiary Consumers
 Acquire energy from flesh
of other carnivores
 Examples: lions, snakes, hawks
Energy
Sun
Energy
 Producers obtain
energy from sunlight or chemicals.
 Energy flows in one
direction through
trophic levels.
Primary Producers
(plants, algae cyanobacteria)
Primary Consumers
(herbivores)
Heat
Secondary Consumers
(carnivores)
Heat
Detritus
Heat
Heat
Detritivores
(bacteria,
fungi, etc.)
Heat
Sun
Energy
 Producers obtain
energy from sunlight or chemicals.
 Energy flows in one
direction through
trophic levels.
Nutrients
Primary Producers
(plants, algae cyanobacteria)
Primary Consumers
(herbivores)
Nutrients
 Producers build
organic molecules
using inorganic
compounds found in
soil or water.
 Decomposers break
organic molecules
down into inorganic
compounds, which
are released into
soil or water.
 Nutrients are recycled by producers
Secondary Consumers
(carnivores)
Detritus
Inorganic
Nutrients
Detritivores
(bacteria,
fungi, etc.)
Energy
Nutrients
Sun
Energy
 Producers obtain
energy from sunlight or chemicals.
 Energy flows in one
direction through
trophic levels.
Primary Producers
(plants, algae cyanobacteria)
Primary Consumers
(herbivores)
Heat
Secondary Consumers
(carnivores)
Heat
Nutrients
 Producers build
organic molecules
using inorganic
compounds found in
soil or water.
 Decomposers break
organic molecules
down into inorganic
compounds, which
are released into
soil or water.
 Nutrients are recycled by producers
Detritus
Heat
Inorganic
Nutrients
Detritivores
(bacteria,
fungi, etc.)
Heat
Heat
Sun
Producers
90% of
energy
lost as
heat
Energy
transferred to
consumers
NUTRIENT
CYCLING
Consumers (herbivores, predators,
parasites, detritivores)
90% of energy
lost as heat
Physical
environment
Decomposers
break down the
remains of dead
organisms,
returning the
inorganic nutrients
to the environment
• Only about 10% of
energy is transferred
to organisms at the
next trophic level
• If 10% of solar
energy is captured
by plants then
animals who eat the
grass gain only 10%
of that energy (1%),
animals who those
animals gain 10%
from that (.1%)
• 10% --> 1% --> .1%
Is all the energy that the plant obtains from the sun
transferred to a mouse?
NO! Energy is needed for life!
(The plant uses some of the energy for life processes, such
as cellular respiration, growth, reproduction, etc…)
Energy
Tertiary
Consumers
10 kcal
10%
Trophic Level
Secondary
Consumers
10%
1,000 kcal
10% of energy is
transferred
Primary
Consumers
100 kcal
Producers
10,000 kcal
CARNIVORES
Quaternary
consumers
Carnivore
Carnivore
Tertiary
consumers
Carnivore
Carnivore
Secondary
consumers
Carnivore
Carnivore
Primary
consumers
Herbivore
HERBIVORES
Zooplankton
Primary
producers
Plant
TERRESTRIAL
FOOD CHAIN
Phytoplankton
MARINE
FOOD CHAIN
PLANTS
Quaternary
consumers
Carnivore
Carnivore
Tertiary
consumers
Carnivore
Carnivore
Secondary
consumers
Carnivore
Carnivore
Primary
consumers
Herbivore
Zooplankton
Primary
producers
Plant
TERRESTRIAL
FOOD CHAIN
Phytoplankton
MARINE
FOOD CHAIN
FOOD CHAIN
Quaternary
Consumers
(Carnivores)
Osprey
Bald Eagle
Tertiary
Consumers
(Carnivores)
Secondary
Consumers
(Carnivores)
Primary
Consumers
(Herbivores)
Producers
Gulls &
Terns
Wading Birds
Large Piscivorous
Fish
Sea Ducks
Small Plankivorous Fish
Zooplankton
Bivalves
Benthic
Invertebrates
Phytoplankton
Tundra Swan
Herbivorous
Ducks
Aquatic
Vegetation
Geese &
Mute Swans
Vegetation
Energy
90% of energy contained
in living tissue is lost as
heat or waste as it
passes from one
trophic level to
the next.
Heat
Heat
Heat
Only 0.1% of energy made by Producers
reaches Tertiary Consumers
Only 1% of energy made
by Producers reaches
Secondary Consumers
Only 10% of energy made
by Producers reaches
Primary Consumers
Heat
Producers
manufacture 100%
of biological energy.
1 Fox
Numbers
As energy flows up
Through the trophic
levels, fewer individuals
can be supported
at each level.
25 Birds
250 Grasshoppers
3000 Grasses
Biomass
Total weight of all the
living organisms within
the trophic level.
The biomass that can be
supported decreases as
energy flows up
through trophic
levels.
1 kilogram of
human tissue
10 kilograms
of beef
100 kilograms
of grain
20,000 kcal from
grain will supply
2,000 kcal of beef –
enough to feed 1
person for 1 day.
20,000 kcal from
grain will feed 10
people for 1 day.
Humans
Cattle
Grains
Humans
Grains
Krill
Krill
Fish
Krill
Krill
Fish
Krill
Turtle
Krill
Krill
Krill
Fish
Krill
Krill
Krill
Fish
Krill
Krill
Fish
Krill
Turtle
Krill
Krill
Krill
Fish
Krill
Krill
Krill
Fish
Krill
Krill
Krill
Fish
Krill
Krill
Krill
Krill
Eagle
= DDT
Turtle
Fish
Bioaccumulation &
Biomagnification
Human
1,000 X (???)
1. Toxins are washed into
water and build up in
sediment and plant life.
5
2. Bottom-dwelling
animals like zebra
mussels concentrate the
toxins when they eat
phytoplankton & algae.
Small mouth bass
200X
3. Gobies and other small
fish ingest the toxins
when they feed on the
zebra mussels.
4. Predator species like
bass continue to
concentrate toxins by
eating the small fish.
5. Humans then ingest the
toxins when we eat the
larger fish (bass, perch,
walleye, etc.).
4
3
1
2
Green algae
X
Goby
40X
Zebra mussels
5X