NCEA Level 2 Biology (90461) 2010 — page 1 of 3
Assessment Schedule – 2010
Biology: Describe concepts and processes relating to ecology (90461)
Evidence Statement
Q
Achievement
Describes biological concepts and
processes relating to ecology by:
recognising, naming, drawing,
giving characteristics of, or an
account of.
ONE
(a)
(b)
Explains biological concepts and
processes relating to ecology by:
providing a reason as to how or why
something occurs.
Achievement with Excellence
Discusses biological concepts and
processes relating to ecology by:
showing understanding by linking
biological ideas.
Gives a description of habitat:
Eg, place where an organism or a
community of organisms lives.
Defines niche appropriately.
Eg, describes features such as
whether the species is active at
night or during the day, what it
eats, where it lives, and other
aspects of day-to-day life.
Eg, the role or way of life of the
organism in the environment.
(c)
Achievement with Merit
Describes TWO of three types of
adaptations appropriately from
structural, physiological and
behavioural.
Structural (or morphological)
adaptations are the physical
features of the organism. These
include things you can see, like its
shape or body covering, as well as
its internal organisation.
Physiological adaptations relate to
how the organism’s metabolism
works. These adaptations enable
the organism to regulate their
bodily functions, such as breathing
and temperature, and perform
special functions like excreting
chemicals as a defence mechanism.
Behavioural adaptations are
learned or inherited behaviours that
help organisms to survive, for
example, the sounds made by
whales.
2a
Explains the fact that the way in
which the habitat is used is actually
what avoids competition, so two or
more species may use the same habitat
in different ways or at different times
and therefore be able to co-exist in the
same habitat without significant
impact on the other(s). The niche of an
organism must be used in this
explanation as in the ‘Achievement’
column. Named examples may be
used but are not necessary.
Explains how adaptations help an
organism survive in its niche
Discusses why adaptations help an
organism survive in its niche
Gives an appropriate example from
any TWO named categories
As Merit in all THREE categories,
with at least TWO of these clearly
stating how the adaptation actually
benefits the organism.
Eg, the streamlined body shape of a
dolphin is a structural adaptation that
enables it to be an efficient swimmer.
Eg, harrier hawks hunt for rats and
mice during the day; this behavioural
adaptation reduces inter-specific
competition with other birds.
Eg, the cave weta has an ‘anti-freeze’
component to its blood which stops it
freezing. This is a physiological
adaptation.
Eg, streamlining of a shark allows it to
be an efficient swimmer and its
counter shading allows it to be better
hidden in the water column, therefore
more able to remain unseen by its
prey.
Eg, shoaling fish that swim as a
coordinated group in the same
direction can confuse their predators
and decrease the chances of
individual capture.
Eg, making venom is a physiological
adaptation that enables animals such as
snakes to paralyse prey, therefore
increasing predation success.
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NCEA Level 2 Biology (90461) 2010 — page 2 of 3
TWO
(a)
Describes what is happening at
points A and B in simple terms, eg
at point A, the population is
growing; at point B, the population
size is steady.
AND describes ONE of the terms
appropriately:
Natality:
Eg, the birth-rate, which is the ratio
of total live births to total
population in a particular area over
a specified period of time.
Explains the relationship at BOTH
points in terms of birth AND death
rates:
At point A the natality is higher than
the mortality i.e. the birth rate
exceeds the death rate and therefore
the population is growing.
At point B, the natality and mortality
must be approximately equal, as the
birth rate is the same as the death
rate and the population size remains
roughly static.
Mortality:
Eg, the death-rate, which is the
ratio of total deaths to total
population in a particular area over
a specified period of time.
OR
Describes Natality AND Mortality
correctly.
(b)
Eg: intra-specific competition
occurs when there is competition
for resources between members of
the same species
This affects population size.
Explains that the population
fluctuates around the carrying
capacity due to variation in the levels
of competition between members of
the same species. In zone C some
resource(s) must be in limited supply
for some of the time.
(One cycle explained)
Discusses the pattern to clarify the
wave-like change in population
numbers that results from competition
between members of the same
species. The population grows to
exceed the carrying capacity of the
habitat / ecosystem. Peaks occur when
the population growth exceeds a
critical resource, this results in high
levels of intra-specific competition,
which in turn causes a decline below
the carrying capacity. At this point the
competition between individuals in the
population is reduced and the
population starts to increase once
more.
The cycle continues / oscillates as the
population’s demand exceeds or falls
below the critical resource availability.
1a
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1e
Describes intra-specific
competition limiting the population
NCEA Level 2 Biology (90461) 2010 — page 3 of 3
THREE
Accept a reasonable
description of succession that
must include species
replacement and time as key
concepts.
Eg, the replacement of one
species by another, over time.
Explains the process of competitive
replacement in both types of
succession:
Eg: primary succession is where the
conditions are originally unfavourable
for plant growth, such as bare rock
created by volcanic activity,
earthquake or landslip. May say ‘on
new land’ or similar.
Gradual erosion and deposition in the
area allows early (hardy) pioneer
species to colonise and survive. These
modify the environment, allowing
competition from other species that
eventually displace the pioneers. The
process of competitive replacement
(accept seral change) continues, until
there is no further change. This is the
climax community.
Secondary succession occurs after
existing vegetation is removed, such as
after a flood, fire or mechanical
(agricultural) process. The soil is
already fertile, so plants can easily
become established. They are usually
easily wind-dispersed or the seeds /
spores were already in the soil.
Discusses the link between how the
differences of the two types of
succession lead to a difference in the
rate of colonisation.
In primary succession the area is
initially unsuited to almost all species,
and the resources that are required by
most new colonisers take a long time
to be formed / accumulate by the
processes of erosion and deposition
(accept import / immigration of organic
material). The process of competitive
replacement therefore takes a long
time to get started.
In secondary succession, many of the
requirements for colonisation already
exist. Soil and other organic material
will be present, allowing a greater
number / variety of colonising species.
A seed bank (don’t need to use this
precise term, but meaning can be
implied) is likely to exist, so many
colonising species are already in the
area, which means that the rate of
development of the pioneer
community will be much faster, and
the competitive replacement process
can continue much sooner.
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1a
Judgement Statement
Achievement
Achievement with Merit
Achievement with Excellence
2 A
2M
2E