NCEA Level 2 Biology (90461) 2011 — page 1 of 3
Assessment Schedule – 2011
Biology: Describe concepts and processes relating to ecology (90461)
Assessment Criteria
Achievement
Achievement with Merit
Achievement with Excellence
Describe biological concepts and
processes relating to ecology requires
the candidate to recognise, name, draw,
give characteristics of or an account of
biological concepts and processes
relating to ecology.
Explain biological concepts and
processes relating to ecology requires
the candidate to provide a reason as to
how or why something occurs with
regards to biological concepts and
processes relating to ecology.
Discuss biological concepts and
processes relating to ecology requires
the candidate to show understanding
by linking biological ideas. It
involves justifying, relating,
evaluating, comparing and
contrasting, and analyzing biological
concepts and processes relating to
ecology.
Evidence Statement
Question
Expected coverage
Achievement
Merit
Excellence
ONE
Describes both
zonation and
stratification, and
provides an example
of each.
Describes BOTH
processes (and gives
at least 1 example)
Provides ONE statement with an
example.
Compares and contrasts
the nature of BOTH
patterns with examples.
Explains how the
patterns occur and the
abiotic factors that
are involved in
creating these
patterns.
Compares and
contrasts the two
patterns to identify
the similarities and
differences in their
nature and occurrence
and gives reasons for
these.
• Zonation is the
division of an
ecosystem into
distinct zones /
bands / regions / in
horizontal layering
due to an
environmental
gradient (abiotic
conditions).
Example: rocky
shore.
• Stratification is the
division of an
ecosystem into
distinct zones that
experience similar
abiotic conditions in
a vertical
orientation.
Example: tropical
rain forest.
• The pattern of zonation is due
to different tolerance of
species to one or more abiotic
factors (may say
environmental gradient). These
should be appropriate to the
habitat.
Eg, exposure to air, salinity,
temperature etc.
• The vertical stratification that
occurs within forests results
from the varying degrees of
key abiotic factors that the
different strata are subject to.
(light, temperature, humidity,
wind etc.),.
Eg. the taller the plant and the
more foliage it produces, the
more light it can intercept.
Links the TWO patterns
(so there must be an
explanation of both),
clearly discussing the key
similarities and
differences – vertical vs
horizontal as being the
way in which distinct
sections of the patterns
are differentiated, but
that abiotic factors are
the key driver of the
pattern formation. The
abiotic factors in
stratification are
themselves influenced by
the nature of the plants.
NCEA Level 2 Biology (90461) 2011 — page 2 of 3
Question
Expected coverage
Achievement
Merit
Excellence
TWO
(a)
The three terms are
described, and an
example of each
provided.
Describes at least
THREE statements.
Explains at least THREE
statements from Merit.
Justifies the importance
of nutrient cycles (Bullet
point 1) AND contrasts
the two processes with
examples
(b)
(c)
Explanation of why
food chains are
normally limited to a
few steps, because of
the limited amount of
energy that is passed
from one level to the
next.
Description of what a
nutrient cycle is.
Explains the
importance of
nutrient cycles to an
ecosystem.
Discusses how they
differ from the
energy flow of food
chains / webs.
In (a) describes:
• Producer:
A photosynthetic
green plant or
chemosynthetic
bacterium that is the
first trophic level in
a food chain; an
autotrophic
organism; eg
phytoplankton
Primary consumer:
An animal that eats
green plants
(producers) in a
food chain; a
herbivore, eg
zooplankton
• Carnivore:
An animal that
feeds on other
animals. eg shrimp,
flounder, squid, furseal, killer whale
In (b)
• Describes the loss
of energy from one
trophic level to the
next (no
explanation).
In (c)
• Describes a nutrient
cycle, eg nutrients
move from the
physical
environment into
living organisms,
and subsequently
are recycled back to
the physical
environment.
Provides at least
ONE example
(details of minerals
involved are NOT
required), eg carbon
cycle.
In (b) provides explanation
for the limited nature of most
food chains.
• There is an energy loss of
about 90% from one trophic
level to the next due to
respiration / metabolism,
therefore a food chain with
only a few trophic levels
results in more energy being
available to the final trophic
level.
• Most other ecosystems have a
lower growth / production rate
and cannot provide sufficient
transferable energy for such a
long food chain.
In (c) Provides at least one
example to:
• Explain the importance of
nutrient cycles to ecosystems
E.g. Without them the
nutrients would be unavailable
to living organisms and
ecosystems would be
unsustainable.
• Explain nutrient cycle, eg that
nutrients move from the
physical environment into
living organisms, and
subsequently are recycled back
to the physical environment.
• Explain one difference, eg
renewable vs non-renewable.
• Without nutrient cycles,
living organisms could
not access the nutrients
and ecosystems would
be unsustainable.
OR the regulation of
nutrients by a cycle
prevents an imbalance
and perhaps the
collapse of the
ecosystem.
AND
The fact that nutrient
cycles are the
movement of
substances in a cyclical
process that involves
constant re-use and
recycling.
OR
• The source of nutrients
in any cycle is finite,
AND
• This contrasts to the
energy flow in foodchains and webs, which
is uni-directional.
OR
• Food chains and food
webs rely on a source of
energy which is
constantly renewed
(ultimately by the sun).
NCEA Level 2 Biology (90461) 2011 — page 3 of 3
Question
Expected Coverage
Achievement
Merit
Excellence
THREE
Describes inter- and
intra-specific competition
accurately.
Describes at least
THREE statements from:
Explains any TWO
statements from:
Provides TWO (linked)
statements.
• Defines inter-specific
competition as
competition between
members of a different
species.
Explains that:
Discusses the relative
impacts of environmental
change and competition
linking explanations of
both to a reasoned
conclusion.
Explains what
adaptations are and how
they allow species to
avoid competition.
Discusses the impact of
environmental change on
biodiversity and why it is
likely to have a greater
impact than competition
from introduced species.
• Defines intra-specific
competition as
competition between
members of the same
species.
• Describes an adaptation
as the evolutionary
process whereby a
population becomes
better suited to its
habitat (accept other
reasonable
descriptions).
• Names and describes at
least two types of
adaptation from:
structural (physical);
physiological;
behavioural.
• Defines biodiversity as
the diversity (number
and variety of species)
of plant and animal life
within a region.
• Environmental change
tends to reduce
biodiversity.
• Inter-specific
competition is likely to
increase when new
species are introduced
to an area but that the
native bees seem to be
competing well.
• Adaptations of the
native bees in terms of
their structure,
physiology and
behaviour make them
better suited to exploit
the native vegetation of
NZ compared to the
introduced species
which are more likely
to be successful on
introduced plants from
their own parts of the
world.
• Environmental change
is mostly caused by
human activity, which
over the last
millennium has been
significant in terms of
loss of habitat and
resources, which has
significantly reduced
the biodiversity in
many areas.
• The reduction in
biodiversity brought
about by environmental
change is likely to have
reduced available food
and habitat sources for
the native bees, which
in turn may lead to local
extinction or reduction
in population size.
• The competition from
the introduced species
is less direct as many of
these species are better
adapted to live and feed
on plant species that
have also been
introduced as part of the
settlement of humans in
NZ. The native bees can
out-compete the
introduced species as
they are better adapted
to the native
environment.
Judgement Statement
Achievement
Achievement with Merit
Achievement with Excellence
2A
2M
2E