Download a local ecosystem

A LOCAL ECOSYSTEM
REVIEW QUESTIONS
ANSWERS
a. MULTIPLE CHOICE
1) c.
2) d.
3) b.
4) a.; P = Ap/a
= 30 x 20/5
= 120
5) c.
6) b.
7) a.; b. does not start with a producer, the arrows are back to front in c.; d. starts with a top order
consumer instead of a producer.
8) d.
9) d.
10) a.; water is buoyant, viscous, temperatures stay relatively stable, nutrients are usually readily
available, but water and oxygen are limited.
b. SHORT ANSWER AND LONGER RESPONSE QUESTIONS
11)
light
Abiotic factor
Terrestrial environment
Readily available.
water availability
Varies
oxygen availability
Readily available.
buoyancy
Air offers little buoyancy, so
terrestrial organisms must develop
structures to support themselves.
Air has low viscosity.
viscosity
nutrient availability
temperature variation
Varies according to the substrate
material in a particular location.
A large range of temperatures
occur on land.
Aquatic environment
Light penetration
decreases with increasing
depth.
Readily available, but
access may depend on
osmotic factors.
Limited availability;
amount of dissolved
oxygen decreases with
depth and increases with
decreasing temperature.
Water provides a high
level of buoyancy.
Water is more viscous
than air, so it is harder to
move through.
Usually readily available in
dissolved form.
Usually experience less
fluctuations than on land.
REVIEW QUESTIONS
ANSWERS - continued
12)
gum tree
borers
beetles
slaters
pygmy
possums
millipedes
spiders
centipedes
large birds
bacteria and
fungi
13) a. Energy and matter are lost as heat or as the result of metabolic processes before they reach the
next level.
b. yabbies: 30,000 kg; fish: 3000kg; eels: 300 kg; crocodiles: 30 kg
14) a. behavioural; although the actual dilation of blood vessels on the surface of the forearms to allow
for evaporative cooling is a physiological adaptation.
b. structural; this provides insulation by restricting heat loss
c. behavioural
d. physiological
e. physiological
f. structural
g. structural
h. physiological
15) a. Gause stated that interspecific competition will always result in the less competitive species
dying out. The result is that similar organisms have evolved slightly different ecological
requirements so that they can occupy slightly different niches.
b. food, shelter, water
16) curve a): eels; curve b): crocodiles, because the population curve for the crocodile, which preys on
eels, will always lag behind the curve for the eels
REVIEW QUESTIONS
17)
ANSWERS - continued
Type of relationship
predation
alleopathy
parasitism
mutualism
commensalism
Definition
A detrimental relationship in which one
organism kills and eats another one.
A detrimental relationship in which one
plant reduces the growth of another one in
its vicinity by secreting inhibitory
chemicals.
A relationship in which one organism uses
another organism (the host) as its food
source. The host is adversely affected, but
does not usually die.
A necessary beneficial relationship
between two organisms; both need each
other for survival.
A relationship between two organisms in
which one or both benefit; neither are
harmed.
Example
crocodiles eating eels
Eucalypt species producing toxic chemicals
that inhibit the growth of other seedlings
under them.
A tapeworm feeding on digested food in the
human intestine.
Lichens, which are algae and fungi living
together - the alga provides food and the
fungus provides support and stores water.
Epiphytic ferns attached to the trunks of
trees as a means of support.
18) a. Some animal populations such as reideer can only survive if members of that particular species
move around together in large herds as protection against predators.
b. Populations of the European rabbit are not present in northern Australia because of its extended
periods of hot weather which severely reduce their fertility.
c. Studies of marine worms in Sydney have found that they are limited to areas with dissolved
oxygen concentrations above 1.5 mg/ml.
19) a. and b. Moisture – The moisture content of the air or soil can be tested using either the probe of a data
logger, or cobalt chloride paper. This paper must be stored over calcium chloride in an airtight
container before use. When exposed to moisture, the paper will change from blue to a pink or
white colour. The time taken for the paper to dry out again is a measure of the moisture present.
Light intensity – This can be measured using the relevant probe on a data logger or a light meter.
Acidity –Water can be collected in a test tube and tested with the appropriate probe on a data
logger, or several drops of universal indicator solution can be added and the resulting colour
checked against a pH colour chart. Soil can be mixed with water in a test tube and tested for pH in
a similar manner to the above method, or wet universal indicator paper can be held against soil
or rocks.
20) Random quadrats are usually wooden frames of dimensions 1m x 1m. They are thrown down
randomly in the area to be studied and for each quadrat numbers of a particular species are
counted several times and then averaged. After the selected number of quadrats has been
sampled, an average count is taken for all of them. This will produce an average estimate of the
number of the species per square metre. This number is multiplied by the total area of the
region studied.