Download Ecological Pyramids

KEY TERMS
Ecological pyramid
Energy pyramid
Numbers pyramid
Biomass pyramid
Trophic level
TROPHIC LEVELS
We have already learned about trophic levels on
food chains
Organisms in the food chain rise from the
producers all the way up to the top carnivore
PYRAMIDS
Ecological pyramids are used by ecologists to
illustrate certain characteristics of food chains
and food webs.
They show certain relationships that exist
between the different trophic levels
TYPES OF PYRAMIDS
• There are three types of ecological pyramids:
•
•
•
Energy
Numbers and
Biomass
ENERGY PYRAMIDS
• All organisms require energy to live
• They contain energy within themselves
• Energy is measured in calories or Joules
ENERGY PYRAMIDS
Energy pyramids are shaped in a conventional way. That
is, in an ecosystem, low trophic levels (i.e. producers),
have the most energy and high levels have the least
In fact, as energy flows from one level
to the next, only about 10% of the
energy remains. That’s because the
rest of the energy is used by the
organism for it’s life processes
BIOMASS PYRAMIDS
Biomass pyramids show the relative mass of living
organisms at each trophic level
Just like energy pyramids, the lower trophic levels in an
ecosystem have the most biomass and the upper
levels have the least
NUMBERS PYRAMIDS
Number pyramids can be a little different than
the other two; but don’t have to be
It depends on the ecosystem
Sometimes they appear the same as energy and
numbers; highest numbers at the lowest level
NUMBERS PYRAMIDS
But not always.
For example, in some forests, huge trees make up the
lowest trophic level and, while there aren’t that many
of them compared to the next level (insects, birds…),
they have the most mass and energy . So number
pyramids can look inverted
NUMBER PYRAMIDS
They can look conventional
Or they can be somewhere in between
TIME TO DO SOME WORK!!!
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