Download Assessment Schedule 2010 AS 90461 (Biology 2.5) Describe

Assessment Schedule 2010
AS 90461 (Biology 2.5) Describe concepts and processes relating to ecology
Question
ONE
Achievement
Sufficiency :
Describes three factors that
act to set upper and / or
lower limits to zones
including one biotic and one
abiotic and describes two
adaptations of a named
organism.
Merit
Excellence
As for Achieved and
explains two factors that
set limits to zones and
explains two adaptations
of a named organism.
As for Merit and
explains three factors
that limit zones.
Answer is a
comprehensive
account of the factors
that determine which
zones organisms
occupy and why.
Explains biotic factors eg
Discussion needs to
link explanations into
a comprehensive
answer which takes
into account the
organism’s
physiological
tolerance in
determining the zone
it occupies.
Note examples given are for
rocky shore; examples from
other named communities
may be given as appropriate.
Describes biotic factors that
may restrict an organism to a
particular zone eg

Interspecific competition
eg for space on the rocks
between barnacles and
mussels

Predation eg by whelk on
barnacles

Food availability eg
mussels in lower zone to
have more time to filter
feed

Parasitic / mutualistic /
commencal relationships
may also be relevant
dependent on community
and organisms that

Being outcompeted
for eg space on the
intertidal rocks will set
upper and / or lower
limit to zone that the
organism can
successfully live in

Predation may set
upper and / or lower
limits to zone as
individuals get
predated if they go into
a zone occupied by
predators

Predators will be
restricted to zones
inhabited by their prey.
Filter feeders that need
occupy it.
large amounts of food
will have upper limit of
zone set by the time
they need to be
covered by the tide as
this brings the food
Abiotic factors that may
restrict an organism to a
particular zone eg

Tidal height eg seaweed
in low zone to be covered Abiotic factors explained
by water most of time
eg

Temperature eg mussels
in low zone as need
cooling effect of water
coverage

Light intensity / substrate
type / salinity / pH /
drainage / wind exposure
may all be relevant
abiotic factors dependent
on community and
occupants
Adaptations eg

Hard shell of eg limpet,
whelk, mussel to protect
against wave action

Use of glue to attach to
rock eg barnacle

Production of free
swimming larvae eg
barnacles, mussels


Tidal movement
determines how long
the organisms are
exposed to eg food
supplies, high
temperatures, oxygen
supplies. The
organisms
physiological
tolerance to these can
set both upper and
lower limits to zones

Temperature
dehydrates organisms;
the physiological
tolerance to
dehydration will
therefore set both
upper and lower limits
to zones
Adaptations explained eg

Organisms need a hard
covering eg shell to
withstand the battering
action of the waves
which will damage
their soft tissue

Organisms need to be
Ability to close up (shell)
when tide out eg mussel,
whelk, periwinkle.
able to attach securely
to the rocks to avoid
being swept off by
tidal and wave
movement
TWO

Free swimming larvae
needed to disperse the
species to prevent over
crowding / reduce
intraspecific
competition for space
on the rocks

Ability to close eg
shell needed to prevent
dehydration / keep gas
exchange surfaces
moist when tide is out.
Describes entry via
photosynthesis; passage by
feeding along the food web /
food chains; exit via
respiration.
As for Achieved and
explains the process of
photosynthesis and the
process of respiration in
terms of energy
transformation /
conversion.
As for Merit and
explains fully the
processes of
photosynthesis,
respiration, and
energy passage
through the food web.
Describes any TWO of eg :
Explains any TWO of eg :
Discussion needs to
link all THREE
explanations into a
comprehensive
answer that includes
an explanation that all
the energy entering
the food web in the
process of
photosynthesis is
eventually lost as heat
in the process of
respiration. Therefore,
energy flows through
Sufficiency :

Energy enters

community in process of
photosynthesis carried
out by green plants which
are the producers for the
community / food web

Energy passes through
the food web as the
producers are eaten by
the herbivores which are
eaten by the carnivores

Photosynthesis
converts solar / light
energy into chemical
energy in the form of
glucose / starch
making it available to
the food web.
Herbivores consume
the chemical energy /
glucose / starch from
by the producers

(’food’) and this fuels
the community (and is
their life processes eg
not cycled).
growth, reproduction.
Carnivores in turn eat
the herbivores gaining
chemical energy to fuel
their life processes.
Energy leaves the food
web as heat in the
process of respiration
carried out by all
organisms

THREE
All organisms respire
to release the energy
from their food /
glucose to make it
available to fuel their
life processes. The
chemical energy in the
glucose is converted to
ATP and heat which is
given off / lost as
‘waste’ energy.
Describes any two reasons
for possum success and any
two reasons for their control.
As for Achieved and
explains any two reasons
for possum success and
any two reasons for their
control.
As for Merit linked to
reduced biodiversity
of NZ forest
communities.
Describes success eg
Explains success eg

Abundant food sources


No natural predators

Temperate climate
Abundant food (unlike
Australia) means
possums healthy and
breed successfully so
increasing population

No natural predators
(unlike Australia)
means no natural
control agents for
possums so population
increases unchecked
Discussion links
explanations into a
comprehensive
answer which
includes an
explanation of the
reduction of
biodiversity in NZ
native forests as a
result of possum
activity and numbers.

Climate is not harsh
Sufficiency :
and describes need for
control eg

Eats leaves / new growth
/ fruit of native trees
which stunts growth /
kills them

Eats eggs / young of
native birds which kills
them and reduces /
endangers population(s)
(unlike Australia) so
no harmful events eg
bush fires / drought /
too hot so
hyperthermia / too cold
so hypothermia – all
these factors can kill /
control populations
and explains need for
control eg

Fewer trees through
possums eating habits
means habitat
destruction for native
species eg birds so
their populations
reduce / become
endangered

Eating and reduction of
trees means less food
for native species eg
birds so also reducing
their populations /
endangering them

Eating eggs / young
birds reduces
populations and so
endangering them

Stability of food chains
/ webs reduced as
reduced food supplies /
sources through
possum herbivore or
predatory feeding
Judgment Statement
Achievement
Two questions answered
correctly.
Minimum of 2 x A
Achievement with Merit
Achievement with Excellence
All questions answered
correctly including one at
Merit level
All questions answered
correctly including one at
Merit level and one at
Excellence level
Minimum of 1 x M + 2 x A
OR two questions answered
correctly including two at
Merit level.
Minimum of 2 x M
Minimum of 1 x E + 1 x M + 1
xA
OR two questions answered
correctly including one at
Merit level and one at
Excellence
Minimum of 1 x E + 1 x M