21-WEEK ASSESSMENT REVIEW
What is commensalism?
One species benefits with no
harm or affect on the other.
What is mutualism?
Both species benefit from the
relationship.
Ex: an orchid being pollinated by a
nectar collecting wasp
What is parasitism?
One species benefits at the
expense of or harm to the
other species.
Ex: tick feeding on a dog;
mistletoe absorbing
nutrients from an ash tree
Why is overfishing bad?
The fish can’t adapt or reproduce fast
enough
What is the difference between these 2
pyramids?
The top pyramid, each level supports a lesser
amount of biomass.
Bottom pyramid, less phytoplankton can support a
larger amount of zooplankton.
Put the following on the pyramid in order of
greatest biomass, or energy, or total number.
Grass
Wolf
Raccoon
Grasshopper
Wolf
Raccoon
Grasshopper
Grass
3rd Consumer
2nd Consumer
1st Consumer
Producers
How much energy is passed to
the next level?
10%
What happens to the other 90%?
Used by the organisms at that level &
given off as heat
If there are 50,000 kilocalories of
energy at the producer level in a
habitat, how many kilocalories would
be at the tertiary consumer level?
50 tertiary
500 secondary
5,000 primary
50,000 producer
What trophic level contains the most energy?
Primary
Consumer
Tertiary
Consumer
Producer
Secondary
Consumer
Producers
Rabbits and mice are herbivores that feed on
grass. Cats are carnivores & prey on mice.
Rabbits are prey to both cats & foxes. What
would the food web look like for these feeding
relationships?
Fox
Cat
Mouse
Rabbit
Grass
Fox
Cat
Mouse
Rabbit
Grass
Explain which animals would be affected if a
disease killed out all the grass.
All would be affected because of lack of food.
In a habitat, horned toads eat ants
and ants eat grass. What would
happen if the number of horned
toads increased?
The number of ants will decrease &
the amount of grass will increase
Where do herbivores
get their energy?
Producers
Which organisms are herbivores?
Snails, grasshopper, snow geese
Which organisms are carnivores?
Rat, salmon, bald eagle, marsh hawk,
harbour seal, killer whale
Which organisms are omnivores?
Vole, Herring, mosquito
What trophic level of a food web
would be the most damaging if it
died out?
producers
Can you explain why?
All the energy in the system starts with
the producers. All other levels would
run out of food eventually.
The removal of which organisms
would have the greatest affect on
the ecosystem?
Marsh vegetation (grasses)
What happens to dead animal
tissue in an ecosystem?
Becomes nutrients for other
organisms
In the nitrogen cycle, what
organisms that live in soil and on
roots fix or make usable by plants
the greatest amount of nitrogen?
Bacteria fix the most
nitrogen.
What would happen if decomposers
like earthworms were removed from
an ecosystem?
The cycle will be disrupted and
slowed
What is primary succession?
Regrowth of a community on barren
land where no life has inhabited
before
Pseudomonas aeruginosa, a
common bacteria, fights off
competitors by injecting them with
toxic proteins using a needle like
puncturing device…
Good competitor
What are examples of primary
succession?
Oceanic volcano eruptions & glacier
retreats
What species would appear first
during primary succession?
Lichens & mosses
What is secondary succession?
Regrowth of a community after a
natural disaster
Ex: forest fire, hurricane, volcano
eruption
What type of organisms would
grow after soil had formed?
grasses