Practice Quiz: Food Webs and Energy Pyramids
1.
Name: _________________________P.__
The diagram below shows an ocean food web. The arrows
indicate the energy flow.
Bacteria
(a)
Nanophytoplankton
Indicate the three producers of this food web.
Nanozooplankton
Microzooplankton
Macrozooplankton
(1)
(b)
Identify the trophic level of each organism named
below. On the diagram opposite, mark clearly the
arrows of energy flow that support your choice.
(i)
Krill
Phytoplankton
Small fsh
and squid
Macrozooplankton
Emperor Penguins
(1)
Weddell Seal
Ross Seal
Adelie Penguins
(ii)
Large Fish
Weddell seal
Crabeater Seal
Toothed Whales
(1)
(c)
Leopard Seal
Determine the maximum percentage of energy that
may reach emperor penguins from primary
producers.
Baleen Whales
(1)
2. The diagram below represents an energy pyramid and four trophic levels.
IV
(a)
Identify the trophic level of the organisms indicated
below.
I:
III
IV:
II
(2)
100 000 kJ m–2 yr–1
I
(b)
Calculate the approximate amount of energy in
–2 –1
kilojoules transferred in m yr from trophic level I
to trophic level II.
(1)
3.
The diagram below shows a simplified food web for a lake.
(a)
State the initial energy source for the above
food web.
(1)
(b)
Deduce the trophic level of the immature
game fish.
(1)
(c)
In the food web shown, identify one
heterotroph and one autotroph.
heterotroph:
autotroph:
(1)
1
4.
This diagram represents a simple food chain. In which ways is energy lost between the trophic levels?
I.
II.
III.
A.
I and II only
B.
I and III only
C.
II and III only
D.
I, II and III
Heat loss through cell respiration
Material not consumed
Material not assimilated
(1)
Sea water temperature has an effect on the spawning (release of eggs) of echinoderms living in Antarctic waters. Echinoderm
larvae feed on phytoplankton. In this investigation, the spawning of echinoderms and its effect on phytoplankton was studied.
In the figure below, the top line indicates the number of larvae caught (per 5000 litres of sea water). The shaded bars below show
when spawning occurred in echinoderms.
= 0 % to 25 %
= 25 % to 75 %
= 75 % to 100%
The concentration of chlorophyll gives an indication of the concentration of phytoplankton. Note: that the seasons in the
Antarctic are reversed from those in the northern hemisphere.
Number of
echinoderm larvae
(a)
80
0
State the trophic level of echinoderm larvae.
% Spawning of
echinoderm
(1)
(b)
Identify the period during which the spawning of
echinoderm lies between 25% and 75%.
(1)
2
1
0
–1
–2
Sea temperature / °C
100
(c)
Explain the relationship between the seasons and
the concentration of phytoplankton.
(2)
Log10 Chlorophyll
concentration
/ mg m–3
10
1
0.1
0.01
Dec
(d)
(i)
phytoplankton
Mar
Jun
1993
Sep
Dec
Mar
Jun Sep
1994
Dec
Outline the effect of sea water temperature on echinoderm larvae numbers.
(2)
Total
/17
2
Sea temperature /°C
5.