Ecology Study guide
Decomposer
An organism that gets
energy by breaking down
the remains of dead
organisms or animal
wastes.
Producer
An organism that produces its own
food. Examples include algae and
grass
Omnivore
An organism that eats both
producers and animals. For
example: a bat and a human
Herbivore
An organism that only eats
producers
Carnivore
 An organism that eats animals. For
example – an Anteater and a lion
Carrying Capacity
 The size (number) of a population of
species an ecosystem can support.
Population
 The total number of one species in a
given ecosystem.
Limiting factors
 A resource that is so scarce that it limits the
size of a population that uses it.
 Examples include: food resources, land area,
amount of water, etc.
Food web
A diagram that shows
the feeding relationships
between organisms in an
ecosystem
2.Give an example of the
following:
Producer: Flower, grass, tree, algae
Primary consumer: (Always a
herbivore or omnivore) Fish, deer,
bird
Secondary Consumer: Snake, honey
badger, fox
Tertiary: Hawk, Human, Lion
3.What does the sun supply to an
ecosystem?
Energy
4.What do plants use the sun’s
energy to make through the
process of photosynthesis?
Glucose (sugar/food)
5. A meadow experiences a
sudden, unusual freeze. Many
plants and animals die as a
result. The freeze is considered a
______________
_________________.
Limiting factor
6A. Bacteria in human’s
intestines. The bacteria help
digest food and they produce
vitamins that the body needs but
cannot manufacture. The
bacteria receive the nutrients
they need. This is an example of
_______________________.
Mutualism
6b. A deer population and a
rabbit population with limited
resources experience
__________________________
___.
Competition
C) Mistletoe is a plant that
feeds on the branches of oak
trees. Mistletoe takes away from
the nourishment of the trees.
This is an example of
____________________.
Parasitism
D) Tapeworms living inside of
the digestive system of humans.
This causes humans to not
receive proper nutrition and
become ill. This is an example of
_______________________.
Parasitism
E)Cattle egrets (birds)feed near
grazing cattle. The cattle eat the
grass which makes the insects
fly. The birds eat the insects
while the cattle (cows) are not
harmed. This is an example of
_________________________
 Commensalism
F)A tick on a puppy. What is the
tick’s relationship to the puppy?
______________________
Parasitic
G) The relationship between a
prairie dog and a hungry coyote?
______________________
Predator - prey
7. What would happen if there
were no fungi or bacteria
(decomposers) on Earth?
The Earth would have a lot of dead
animals and trash that is not
decomposing. Nutrients also would
not be recycled
Use the chart below to answer
the following questions (8-11)
8. Which of the living things in this food
chain is a producer?
Flower
9. Which is a secondary consumer (look
closely)?
Snake
10. Which organism is a herbivore?
Grasshopper
11. About how much energy is
passed on to each successive
level in an energy pyramid?
__________________________
_____.
 10 percent
12. Using the diagram to the
right, the bottom of the energy
pyramid is made up of which kind
of organisms?
Producers
?
13. From smallest to largest,
correctly list the levels of
environmental organization
 Organism, Population,
Community, Ecosystem, and
Biosphere
14. Give three examples of
abiotic parts of an ecosystem
(non-living):
 Air, rocks, soil, sunlight, and water
15. What are biotic factors in an
environment?
Animals, plants, algae, fungus,
bacteria
16.The graph to the left shows a number of
seaside sparrows and little marsh crabs in
an estuary habitat over a five year period.
In which year was there a disease that killed
off most of the cord grass, a source of food
and shelter for animals in the marsh?
Year 2
17. Why do animals not obtain
nitrogen from the air?
Nitrogen in the air is in a form
animals can not use.
Therefore, we have to get the
Nitrogen from plants and
animals that we eat.
18. What process that plants
undergo removes carbon from
the atmosphere?
__________________________
_____
Photosynthesis
19. Which process occurs when
water vapor passes through the
leaves of plants?
__________________________
__
Transpiration
20. What happens to the carbon
in an organism’s body when the
organism dies?
 Decomposers break down the carbon in
the organisms body and returns that
carbon back to the environment
21. Which will MOST LIKELY happen to
a population of grasshoppers in an
ecosystem where a chemical kills all
of the grass?
A. The population will decrease
because they lost a food supply
22.Circle the organism that
would best fit into the food web
on the left
Owl
23. Where does the grass
ultimately receive all its energy
from?
The sun
24. True or false: The
relationship between the snake
and mouse can be described as a
predator prey relationship.
TRUE
25. Parasite have relationships
with their
Hosts