1. An example of a biotic factor is
A.The number of
worms in the soil
B. The amount of leaf
liter (dead leaves) in
the soil
C. The pH of the soil
D. Both A and B
2. The interaction between the
different species in an area and their
physical surroundings is called
A.a community
B. a population
C. an ecosystem
D. a biosphere
3. A forest has 9,000 trees in an area of 10
square miles. What is the population
density for the trees in this forest?
A.90 trees-mi2
B. 90 trees/mi2
C. 900 trees-mi2
D. 900 trees/mi2
E. 90,000 trees-mi2
F. 90,000 trees/mi2
To calculate population density divide the
population size by the area.
Population Density = Population size / Area
A population of 9,000 trees in an area of
10 mi2 has a density of 900 trees/ mi2.
The unit for the population of trees in this
forest is trees / mi2 pronounced trees per
square mile because the formula involved
dividing the trees by the area.
4. Organisms that can produce their own
food, using sunlight or in a few cases
certain chemical compounds, are called
A. producers
B. autotrophs
C. heterotrophs
D. A and C
E. A and B
5. An example of a chemosynthetic
organism is
A. a yeast cell that is able to ferment
grapes to produce alcohol
B. a bacteria found in hydrothermal
vents that is able to produce
organic food molecules using the
energy found in certain volcanic
compounds
C. both A and B
D. neither A nor B
6. Which of the following words in
synonymous with the word
“consumer”?
A.Autotroph
B. Herbivore
C. Scavenger
D. Heterotroph
7. The diet of a bear includes both meat and
vegetation such as berries and bulbs. With
this type of diet, bears are classified as
A.Carnivores
B. Scavengers
C. Omnivores
D. Herbivores
E. Detritivores
8. A trophic level is
A.a step in a food chain.
B. the amount of sunlight present in an
ecosystem
C. the average temperature in an ecosystem
D. the average amount of precipitation in an
ecosystem
9. A food chain (or web) forms an energy
pyramid, in which the widest part of the
pyramid with the greatest amount of stored
energy and biomass is
A.a top consumer
B. an autotroph
C. an herbivore
D. a decomposer
10. The carrying capacity for the rabbit
population in the graph below is
A.3
B.4
C.30
D.60
E. 65
11. The initial (starting) phase of a
logistic growth graph shows
A.
B.
C.
D.
an exponential increase in the population
a steep linear increase
a decline in population
a gradual linear increase
12. Which of the following could cause
an increase in the carrying capacity of
the rabbit population?
A.
B.
C.
D.
An increase in the supply of food
An increase in the birth rate
Both A and B
Neither A nor B
Organisms generally reproduce at a rate that would
allow for exponential growth.
The carrying capacity of a population is caused by the
factors that limit its growth (food supply, predators etc.)
even though the birth rate remains steady. (increase in
deaths).
The carrying capacity is not a fixed quantity. If the
limiting factors change than the carrying capacity will
13. Which type of species would have
an advantage if there is an unstable
environment?
A. Generalist
B. Specialist
14. A food chain in a pond begins with algae that are eaten
by mayfly nymphs which serve as food for sunfish which are
then consumed by great blue heron.
(algae  mayfly nymph  sunfish  great blue heron )
If this pond becomes contaminated with mercury, which
organism would likely become most contaminated with this
toxin?
A.The algae
B.The mayfly nymph
C.The sunfish
D.The great blue heron
15. If you compared the amount of mercury in a
tuna (a larger fish that is higher on the food
chain) to that in a herring (a smaller planktoneating fish) it would likely have
A. A greater total amount of mercury
B. A higher concentration (grams of mercury
per pound of body mass)
C. Both A and B
D. Neither A nor B
Review:
Remember that food chains form energy
pyramids with less biomass for each level
you move up the food chain. (More algae
is needed to feed the mayfly nymphs etc.)
This is because not all of the energy is
passed through the food chain but is
transferred out of the food chain as heat
energy and waste.
Therefore, the top consumer generally
has the greatest concentration of toxins,
since the same amount of toxin is present
in a smaller quantity of biomass. The top
consumer has had to consume a greater
amount of food from the lower levels.
1.D
2.C
3.D
4.E
5.B
6.D
7.C
8.A
9.B
10.E
11.A
12.A
13.A
14.D
15.C