Ecosystems
• An ecosystem includes all of the
organisms as well as the nonliving
things in a given area.
Ecosystem
Ecosystem
Community
Community
Population
Population
Organism
Organism
• A community is a group of
different species that live
together in one area.
Community
Community
Population
Population
Organism
Organism
An ecosystem includes both biotic and
abiotic factors.
 Biotic




factors are living things.
plants
animals
fungi
bacteria
plants
Abiotic
–
–
–
–
–
factors are nonliving things.
moisture
temperature
wind
sunlight
soil
sunlight
moisture
What is the primary source
of energy for an
ecosystem?
Producers
 Makes
food by changing light energy of
the sun into chemical energy, or food
 Also called Autotrophs
 Ex. Plants, algae, some bacteria
Consumers
 Organisms
own food
 Also
 Ex.
that do not make their
known as HETEROTROPHS
Rabbits, Deer, Mushrooms
Heterotrophs
Heterotrophs
 Consumers
Herbivores – eat ONLY plants
Ex. – Cows, Elephants, Giraffes
 A.
Heterotrophs
 Consumers
Omnivores – eat BOTH
plants and animals
Ex. – Bears and Humans
 B.
Heterotrophs
 Consumers
C.
Carnivores – eat ONLY
other animals
Ex. – Lions, Tigers, Hawks
Heterotrophs
 Consumers
D.
Scavengers/Detritivores –
feed on the tissue of dead
organisms (both plants and
animals)
Ex. – Vultures, Crows, and
Shrimp
Heterotrophs
 Consumers
E.
Decomposers – absorb any
dead material and break it
down into simple nutrients or
fertilizers
Ex. – Bacteria and
Mushrooms
Food Chain
Food Chains
 The
energy flow from one trophic level
(feeding levels) to the other is know as a food
chain
 Producers are at the first TROPHIC LEVEL
 Primary (1st)Consumers are the SECOND
TROPHIC LEVEL
 Secondary ( 2nd) consumers are at the THIRD
TROPHIC LEVEL
 Tertiary ( 3rd) consumers are the FOURTH
TROPHIC LEVEL
Trophic Levels (feeding levels)
3
2
1
Food Web
 Most
organisms eat more than JUST
one organism
 When
more organisms are involved
it is know as a FOOD WEB
 Food
webs are more complex and
involve lots of organisms
Food webs
Trophic
Level
Grass
Mouse
Grasshopper
Frog
Owl
Hawk
Producer, primary
Type of
consumer, secondary
Consumer
consumer, tertiary
consumer
Trophic
Level
Grass
Mouse
Grasshopper
Frog
Owl
Hawk
1st
Producer, primary
Type of
consumer, secondary
Consumer
consumer, tertiary
consumer
Producer
None
2nd Primary consumer Herbivo
re
Primary
2nd
Herbivo
consumer
re
Secondary
Carnivo
3rd
consumer
re
Secondary and Carnivo
3rd
and 4th tertiary consumer re
Carnivo
Secondary
3rd
consumer
re
Transfer of Energy
 When
a lion eats a zebra, it does
not get all of the energy from the
zebra (much of it is lost as heat)
 Only 10% of the energy from one
trophic level is transferred to the
next – this is called the 10% rule
Do you know why there are more
herbivores than carnivores?
In a food chain, energy is passed from one link to
another. When a herbivore eats, only a fraction of the
energy (that it gets from the plant food) becomes
new body mass; the rest of the energy is lost as waste
or used up by the herbivore to carry out its life
processes (e.g., movement, digestion, reproduction).
Therefore, when the herbivore is eaten by a carnivore,
it passes only a small amount of total energy (that it
has received) to the carnivore. Of the energy
transferred from the herbivore to the carnivore, some
energy will be "wasted" or "used up" by the carnivore.
The carnivore then has to eat many herbivores to get
enough energy to grow.
Because of the large amount of energy that is lost at
each link, the amount of energy that is transferred gets
lesser and lesser ...
 The
further along the food chain you
go, the less food (and hence
energy) remains available.
2.
Most food chains have no more than four or
five links.
There cannot be too many links in a single
food chain because the animals at the end of
the chain would not get enough food (and
hence energy) to stay alive.
Most animals are part of more than one food
chain and eat more than one kind of food in
order to meet their food and energy
requirements.
Theseinterconnected food chains form a food web.
Ecological Pyramid
Energy Pyramid
•
•
•
•
•
•
Which level has the most energy?
Which level has the most organisms?
Which level has the least organisms?
Which level has the least energy?
Which Type of consumer ( omni, herbi
Classify the organisms according to their
role in a food web.
Pyramid of Numbers
• Shows the numbers of individual organisms at each
trophic level in an ecosystem.
tertiary
consumers
5
secondary
consumers
5000
primary
consumers
500,000
producers
producers
5,000,000
• A vast number of producers are required to support even a few
top level consumers.
Biomass pyramid
• Biomass is a measure of the total dry mass of
organisms in a given area.
tertiary
consumers
75 g/m2
150g/m2
secondary
consumers
primary
consumers
producers
producers
675g/m2
2000g/m2