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Ecology Review
Question 1
What is ecology and what
do ecologists do?
Ecology is the study of living things and how they interact
with one another and their environment. Ecologists are
people that study these relationships.
An example would be the study of how zebra mussel
populations affect native clam and phytoplankton in U.S.
rivers and lakes.
Question 2
Explain the difference between a habitat and an
ecosystem.
Habitat: The area where a
specific species lives.
Ecosystem: An area that
includes all living organisms
and the abiotic factors that
influence the region (like
weather).
Question 3
What is a niche? Explain how
this impacts an ecosystem when
a species is added or removed.
Niche: A niche is the role that
an individual organism plays
in its nonliving and living
environment (how it "fits"
into its ecosystem).
If a particular niche is already
filled, introducing a species
that requires the same
resources will cause
competition between the
two.
If a certain niche is no longer
filled, the ecosystem will
become unbalanced. For
example, the extinction of a
top predator would allow
prey populations to increase
dramatically.
Question 4
Biodiversity is the
What is biodiversity and
variety of living things.
why
is
it
important?
Depending on the
scientist you ask,
biodiversity can be the
There are many views on why
number of species
biodiversity is important.
living in an ecosystem,
• We need a variety of plants and
genetic diversity
animals to produce medicines.
within a species, or
• Many people enjoy outdoor
the number of species recreational activities.
• We can learn about species
living on Earth at a
from the past by studying current
species.
given time.
• Nature inspires art, music and
cultures.
Question 5
What does a food web represent? How do these
diagrams work?
A food web shows the
flow of energy within an
ecosystem. Arrows point
from food to consumer
because the organism
that’s eating is gaining
energy from the one
being eaten.
Producers, Consumers and
Decomposers.
Producers are the source of
energy for the whole
ecosystem, without them
everything would eventually
die.
Consumers help producers
complete their life cycles by
spreading seeds and
pollinating. They also feed
other consumers and
eventually decomposers.
Decomposers break down
dead organisms and help to
recycle nutrients in an
ecosystem.
Question 6
Within a food web, there are
always ___________,
___________ and ___________.
Why are all three necessary?
Question 7
Trade-off: An exchange of
one thing in return for
another, especially losing
an advantage for another
more desirable one.
What is a trade-off? Give one
example that we have talked
about in class and one
additional example from your
By introducing Nile Perch
own experience.
to Lake Victoria, locals
were given a source of
protein but the lake lost
many species of smaller
fish.
Question 8
What is the difference between biotic and
abiotic factors? Why are both important in an
ecosystem?
Biotic: Living
Abiotic: Non-living (never, ever was
alive…)
All living things play a specific role
in their ecosystem and abiotic
factors help with important
processes and ingredients, like
those necessary in photosynthesis.
- phytoplankton
Question 9
How can introduced species affect an ecosystem?
How do they become invasive? Compare and
contrast the impacts of zebra mussels and swamp
crawfish.
Introduced species have the potential to become invasive. An introduced
species may compete with native species for resources such as food, habitat,
and water. Without natural predators to keep their numbers down, they may
takeover a certain niche within the ecosystem.
Zebra mussels have few natural predators and have been consuming large
amounts of plankton and leaving little to no food for native clams and other
filter feeders. They are spreading through freshwater lakes and rivers in the
U.S.
Swamp crawfish are competing with local crawfish for food and habitat. Their
population is increasing in Pine Lake.
Question 10
What is carrying capacity and
what are some factors that
can impact it?
The Carrying Capacity
of a species is the
maximum population
that can live in an
ecosystem long term.
This can be affected by
changes in climate,
availability of food,
diseases, habitat loss
and more.
Question 11
What is a population? Does it always remain the
same? If not, should we be concerned?
Population: Individuals of the same
species living in the same area.
Example - All of the swamp crawfish
in Pine Lake are a population.
Populations fluctuate (increase and
decrease) so there is only reason to
be concerned if numbers remain
extremely high or extremely low for
long periods or don’t follow typical
patterns for that area.
Question 12
Describe the impacts humans can have on
ecosystems. Be sure to mention Lake Victoria
and Easter Island in your answer!
Humans often have negative effects on ecosystems including
deforestation for construction and farming, pollution from factories
and vehicles, use of pesticides, and more. In Lake Victoria, humans
intentionally introduced Nile Perch which then became invasive
and caused the extinction of many species of cichlids.
On Easter Island, humans unintentionally introduced species that
also caused extinctions. Overconsumption
of resources also led to many extinctions.