Today’s Topic – Ecological
Communities (5.3)
Learning Goal:
SWBAT explain the needs of an organism
based on its trophic level.
 Today we will be completing fill-in notes for
this portion of the book.
 Not all questions are in the notes.
 Answers that have a (#) next to them are the
same across the notes.
Why Do We Need Food?
 Food is delicious. However, there is a
reason why we eat food.
 Why do we eat food?
Energy
 As we know from Physics (and other
sciences), Energy is the ability of a creature
to do work.
 Energy can be changed from one form to
another (heating, moving things, etc.)
Energy
 What did the Law of Conservation of Matter
say?
 Matter can neither be created nor
destroyed.
 Matter can be recycled.
 Energy, however,
cannot be recycled.
Energy
 According to thermodynamics, energy can
change forms, but it will do so inefficiently.
 We can easily heat up a room, but it will
take an input of energy to cool off a room.
 For this reason, we say
that energy only flows in
one direction.
Energy
 What is the best and cleanest energy
source?
 The Sun!
 What types
of creatures
utilize the
Sun to make their food?
 Primary Producers!
Energy
 When primary producers use the energy
from the Sun, they are able to create their
own food using photosynthesis.
 Because primary
producers are able
to make their own
food, they are
referred to as
autotrophs.
Producers
 All of these creatures are autotrophs!
Utilizing the Sun
 What chemical reaction occurs in
photosynthesis?
6CO2 + 6H2O + The Sun’s Energy →
C6H12O6 + 6O2
 In order for photosynthesis to
occur, what else do
plants need?
Utilizing Primary Producers
 Because we’re thinking about food, plants
have now eaten.
 But what about other creatures in the
community?
Utilizing Primary Producers
 Creatures that consume primary producers
are known as primary consumers.
 Primary consumers eat the glucose and
other sugars created from primary
producers.
 By doing this,
primary consumers
get their energy
through cellular
respiration.
Primary Consumers
 Because primary consumers cannot create
their own food, and need to eat other
creatures to get energy, they are known as
heterotrophs.
Primary Consumers
 Primary consumers do not always need to
other living things, however.
 For this reason, there are many types of
primary consumers.
 A primary consumer that only eats primary
producers is known as an herbivore.
Herbivores
 All of these creatures are herbivores!
The Hunter Becomes the
Hunted
 Creatures that eat herbivores, or any
other primary consumer are called
secondary consumers.
 Creatures that only consumer other
primary consumers are called carnivores.
Carnivores
 All of these creatures are carnivores!
The Hunter Becomes the
Hunted
 Creatures that consume either
primary consumers or
primary producers are
known as omnivores.
Omnivores
 All of these creatures are Omnivores!
The Hunter Becomes the
Hunted
 Tertiary consumers are creatures that
consume secondary consumers.
 Quaternary consumers are creatures that
consume tertiary consumers.
 Etc.
Life in Death
 Once a creature dies, they become a
food source for other types of
consumers.
 Creatures that eat dead things are called
detritivores and decomposers.
Life in Death
 Detritivores consume detritus, which is
nonliving organic matter (leaf litter, waste
products, the dead bodies of other
community members)
Life in Death
 Some examples of detritivores are:
Millipedes
Life in Death
 Some examples of detritivores are:
Earthworms
Life in Death
 Some examples of detritivores are:
Vultures
Life in Death
 Some examples of detritivores are:
Fiddler Crabs
Life in Death
 Some examples of detritivores are:
Slugs
Life in Death
 Decomposers are creatures that can
break down nonliving matter into simpler
parts, which can then be used by primary
producers.
Life in Death
 Some examples of decomposers are:
Maggots
Life in Death
 Some examples of decomposers are:
Mushrooms
Life in Death
 Some examples of decomposers are:
Mildew
Your Place in the World
 What would happen if there were no
detritivores or decomposers in a
community?
 Back to feeding levels:
 An organism’s trophic level is its rank in
the feeding hierarchy.
Your Place in the World
 At the base level are primary producers.
 Primary producers are always on the first
trophic level.
Your Place in the World
 From there, the primary consumers,
secondary consumers, and tertiary
consumers make up the second, third,
and fourth trophic levels.
 We do not really see anything past fifth
trophic levels, due to size constraints of
communities.
 Therefore, most communities can only
really support third or fourth tropic levels.
Storing Up for Winter!
 As creatures consume food, only a
certain portion of food is stored for later
use.
 The general rule of thumb is that 10% of
the energy is stored for later use.
 This is known as the Ten Percent Law.
We Are the 10%
 According to the 10% law, only 10% of
the energy from organic matter is stored
as flesh.
 The remaining is lost during transfer,
broken down in respiration, or lost due to
incomplete digestion by higher tropic
levels.