Ecosystem
• A community of living organisms interacting with one
another and with the nonliving components of their habitat.
Ex: lake, forest, jungle, island, mountain..
Trophic Relationships
• Trophic relationships are the feeding connections among the living
organisms in an ecosystem.
All living organisms need energy to survive and they obtain it by feeding
on organisms in their environment.
 Trophic relationships are represented by a FOOD CHAIN
Trophic Levels
• Food chains contain the following trophic levels:
1) Producers
2) Consumers
3) Decomposers
Producers
• These organisms get the energy they need to survive by taking inorganic matter
(matter not produced by living organisms such as rocks, sunlight, water, minerals) and
turning it into organic matter (matter created by a living organism such as leaves,
tree bark, flowers).
 Usually done through photosynthesis
 Can feed themselves without having to ingest other living organisms
 Also called autotrophs
 Introduce energy and matter into
ecosystems
Producers
Biomass: Total mass of organic matter in an ecosystem
Organic matter is made by producers. Producers are constantly turning inorganic
matter into organic matter.
Primary Productivity: Amount of new biomass created by producers in an
ecosystem. This is the amount of energy available for primary consumers.
As primary productivity increases, the number of organisms able to live in an
ecosystem increases (more food available).
Factors that Influence Primary Productivity
•
•
•
•
Amount of light (for photosynthesis)
Amount of water available (for photosynthesis)
Amount of nutrients in the soil
Temperature (warmer weather promotes the growth of producers)
Rainforest
Arctic
Consumers
• Consumers obtain the energy they need by feeding off of
other living organisms.
They are heterotrophs (incapable of producing food for
themselves from inorganic matter)
Can be separated into two types: primary consumers or
second/third/fourth order consumers
Types of Consumers
• Primary (or first-order) Consumers:
-Feed on producers
-Are herbivores/frugivorous
• Second/third/fourth order Consumers:
- Feed off primary consumers
- Are carnivores
**Note: Omnivores are consumers of several orders at once. Ex: a bear can eat plants and
fish**
Decomposers
• Organisms that feed on the waste and remains of other
organisms (organic matter) and turn it into inorganic matter
Feed off detritus (dead organic matter)
Heterotrophs
Also called detrivores
Decomposers & Chemical Recycling
Chemical Recycling: When decomposers make inorganic
available for others in an ecosystem by breaking down
organic matter
Try
This!
1. Which organism can be classified as a Primary
Consumer?
a) Red Tailed Hawk
b) Shrew
c) Willow
d) Snowshoe Hare
2. Which organisms act both as a secondary and tertiary
consumer depending on the individual food chain
they are involved in?
a) Shrew and Red Fox
b) Lynx and Red Fox
c) Lynx and Snowshoe Hare
d) Red Tailed Hawk and Insects
Try This!
Using the above food web, indicate an example of a
producer. Explain why producers can also be called
autotrophs.